In the late ’50s, GM’s Detroit Diesel Division’s “Million Miler” -71 diesel engine was so superior to the competition, resulting in such market dominance that GM was forced by an FTC consent decree to sell it to its competitors.
In the early ’80s, GM’s Oldsmobile Division’s passenger car V8 diesel engine turned out to be such a disaster, the FTC had to step in and broker a massive compensation deal on behalf of millions of its angry buyers.
The 1950s were GM’s golden decade; the 1980s its living hell. And the Olds diesel sprayed plenty of fuel on those flames.
The 1973-1974 energy crisis shook the foundations of The Big Three’s business proposition, which was always tilted heavily to large cars. Detroit built small cars reluctantly because the fat profit margins they had on big cars just weren’t there, if any at all. And realistically, most Americans weren’t going to be happy with the Pintos and Vegas they bought in the depths of 1974 once the OPEC oil taps were turned on again.
In response, in 1975 Congress passed the Energy Policy and Conservation Act, which resulted in CAFE (Corporate Average Fuel Economy), set to take effect in 1978. The initial 1978 target number was 18mpg, tightening up substantially to 27.5mpg in 1985. The energy crisis was becoming an existential crisis for GM.
The first order of business was to start an across-the-board downscale program, which would become to be the biggest corporate investment program to date. Every line was to be completely new, starting with the large B-C Body cars in 1977. Reduced weight and improved aerodynamics allowed the return of six cylinder engines and smaller V8s, resulting in significantly improved EPA mileage numbers.
In the case of this 1977 Chevrolet, compared to the ’76 with its standard 350 V8, the six cylinder version’s EPA rating was a 33% improvement and the 305 V8 version was rated 20% better. A good start, but GM knew that it would have to keep improving those numbers in coming years. That led to various programs to further reduce weight and improve aerodynamics with these B-C Bodies, as well as improved drive line efficiencies. One of those programs resulted in the 1981 Cadillac V8-6-4 engine, with cylinder deactivation. It turned out to be highly problematic, due mostly to its electronic control module being underdeveloped and unreliable.
Other programs included the expanded use of the Buick V6, and Chevrolet developing a 90 degree V6 derivative from its small block V8. And there were lighter and further downsized gas V8s, like the Pontiac 301 and 265, the Chevy 267, and the Olds 260 and 307.
But there was another avenue yet to explore: the diesel. And there were a number of compelling reasons.
GM had of course been keenly aware of the rapidly growing success of Mercedes, and that an increasing percentage of them were diesels. The fact that upscale buyers would gladly pay 2-3 times as much for a slow, sometimes smelly and sooty diesel compared to a big GM sedan must have been painful. A diesel Mercedes was the hot new status item for those that couldn’t quite swing a 450SE or SL.
Peugeot’s 504 diesel was now hot too, injecting new life into what had become a somewhat slow-selling brand in the US. Like Mercedes, Peugeot had a half century of experience in the field. And who is the ad referring to?
And in 1976, VW jumped into the diesel market in a big way. The Golf/Rabbit’s diesel was a direct development (“conversion”) of its gas engine, and showed that it was not necessary to start from scratch in building a successful diesel engine. As such, it offers a counterpoint to the Olds diesel, both being converted gas engines. It resulted in an extremely economical yet surprisingly agile car, changing the image of a modern diesel. And it turned out to be very durable. The Europeans were clearly showing the way forward.
Rudolf Diesel’s namesake engine had a couple of very compelling qualities at the time. It needed no emission control systems, as it inherently had lower outputs of HC and CO, and NOX standards were still very generous at the time. Gas engine emission systems were becoming more complex and expensive with each tightening of the EPA standards.
The diesel is intrinsically more efficient than a gas engine, roughly 25-40% more so for a given displacement (the gap has narrowed in more recent years). In addition to the obvious benefits, this also resulted in significantly longer range between fill ups, another advantage at a time when memories of gas station waiting lines were still fresh. And diesel fuel was still consistently cheaper than gasoline, as a result of the imbalance of demand, taxes, as well as other factors.
Maintenance was potentially reduced, as there was no ignition system, emission system, carburetor, or complex electronic fuel injection system. Oil changes did require shorter intervals (typically 3,000 miles), and the oil capacity was usually greater. But the appeal of the diesel’s intrinsic simplicity and fuel efficiency was naturally compelling.
So in 1975, Oldsmobile, long known as GM’s “experimental division”, began the development of a diesel engine. Before we go any further, let’s quickly address a common refrain: why didn’t GM give the job to Detroit Diesel, which had been building diesels since 1933?
For several good reasons. To start with, Detroit Diesel’s two stroke engines, initially developed by Charles Kettering at GM Labs in very large format, operated quite differently, with its necessary expensive blower. They were also extremely noisy, due to being direct injection as well as being two-stroke engines, which made them sound as if they were running at twice their actual engine speed (dubbed “Screaming Jimmys”). All passenger car engines were then still indirect injection, as the violent percussion of direct injection had not yet been tamed.
I’ve seen one of the smaller DD’s, the 4-53, swapped into pickups, like this one in an International, but it’s not done for practical purposes. They are very heavy, loud and rough, and the two stroke design does not like lots of low rpm use. It was absolutely not suitable for passenger car use.
A more obvious choice might have been the GMC Truck division, which undertook a gas to diesel conversion of its 60 degree V6 engine, which first appeared in 1960. In 1964, the Toroflow diesel appeared, using a strengthened version of the gas V6 block and internal components and of course a new cylinder head. It’s possible that the V6 was designed in the first place with an eye to an eventual diesel version. Regardless, the Toroflow, intended as a more affordable diesel for medium duty trucks and buses, ended up with a fairly mediocre reputation. Its power output was modest, and it just wasn’t quite up to the abuse it got over the long haul. Not a total failure or disaster, but certainly not a memorable engine family. CC’s in-depth story on the Toro-Flow is here.
In any case, the Toroflow’s direct injection “toroidal flow” cylinder head design also was not applicable to passenger car use. Direct injection diesels were not adapted to passenger car engines until the end of the 1980s. Cylinder head/precombustion chamber design was really the key element to passenger car diesels then, other than making sure the engine was robust.
So the job fell to the Olds Engineers, who first started on it in 1975, according to one source. And the Olds 350 (5.7L) V8 engine was the starting point. Why? Why not? There’s actually no good argument for not starting with a well designed gas engine and modifying it to be a diesel. As a matter of fact, the legendary Mercedes OM621/615/616/617 SOHC four and five cylinder diesels built from 1955 until 1991 were very much based on their gas engine counterparts. I suppose more correctly, one might say they were developed simultaneously with the same architecture and some shared parts. The point is, successful diesel engines do not need to be designed from scratch or unique. And it’s been done successfully by others.
In a R&T article, Olds engineer R. James Benner is quoted as saying “there are no textbooks or papers that explain how to build a diesel”. Really? Maybe hire an experienced diesel engineering firm like Ricardo or Porsche? Or better yet, how about taking advantage of the deep diesel experience at affiliate Isuzu, of which GM owned 34% since 1972?
Isuzu had been building its compact precombustion chamber C-Series engines since 1959. A version of that venerable engine is still clattering away today in this 1982 Isuzu I-Mark diesel that I’ve been following for ten years. It just won’t die.
Let’s see: one version of the Isuzu C220 2.2 L four made 73 hp; if they had just doubled that up into a V8 it would have had 4.4 L and made some 145 hp, or 25-40 more than the Olds 5.7. And I’d still be shooting numerous legendary Olds Diesels clattering away hereabouts. Just how hard would that have been? I’m sure Isuzu would have been thrilled at the prospect. But the NIH (Not Invented Here) syndrome was extremely powerful at GM, a curiously deadly strain at that. Meanwhile, I’ve yet to find a genuine Olds diesel on the streets here in twenty years, despite millions having been made.
Ironically, after somewhat mixed results with its later 6.2 and 6.5 diesel light truck V8s, GM finally did turn to Isuzu for the Duramax V8. And it’s compiled a generally excellent reputation over the years, certainly better than the Ford PowerStroke. Oh well.
On to the actual Olds diesel:
Olds engineer Benner said they put together what seemed to be a proper diesel V8 and said “Let’s run it and see what falls apart first. That engine lasted about 30 minutes. So we built another, correcting the faults of the first, and ran that to see what would fall apart second, and on and on”.
That’s all good and well, if you’re going to start from scratch to reinvent the diesel. But the deadly problem is that development and durability testing was cut short, to satisfy the sales and marketing guys, as well as the bean counters. From a 1983 New York Times article:
Darrel R. Sand, a former G.M. engineer who helped design the Oldsmobile V-8 diesel engine, is not surprised. He said last week that he had strongly advised his superiors at the company against putting the engine into production back in 1977 and 1978, but he said that his objections were ignored because the company needed the fuel-efficient diesel in order to meet fuel economy standards for its fleet.
”In test after test, we had broken crank shafts, broken blocks, leaking head gaskets and fuel pump problems,” Mr. Sand said. ”The diesel couldn’t hold up, it was a hastily converted gasoline engine with a fuel pump designed for heavy trucks.”
In 1980, Mr. Sand said he was forced to retire for causing such a fuss about the diesel. G.M., however, would not comment on Mr. Sand’s charges.
But that doesn’t quite tell the whole story either.
Although the Olds 350 block was modified for diesel use, with larger bearing areas and such, and its internal components were strengthened, the critical issue was in the cylinder head studs. In order to maximize production efficiency and have the diesel block run down the same transfer line (milling, machining, drilling), the number of cylinder head studs was not increased from the 10 per side as can be seen on this gas 350 block. Diesel engines have compression ratios up to 3x that of gas engines, thus the forces acting on the heads wanting to separate them from the block are much greater. The resultant stretched head bolts caused leaking head gaskets, which allowed coolant into the combustion chamber, causing hydrolock and other severe maladies.
The failure to increase the number of studs was a deadly mistake, and one that wouldn’t have been properly fixed without quite considerable investment in new production equipment. GM did make a number of “fixes” to mitigate this issue, with modified heads, stronger bolts and different head gasket material, all of which helped to one degree or another, but by that time, the diesel’s reputation had already caught up to it. The improved DX block version that arrived in 1982 was beefed up in a number of ways, and was essentially what it should have been in the first place.
The 4.3 L V6 that came out in 1982 did have a denser head bolt arrangement, and did not suffer the catastrophic head sealing failures of the V8.
The second deadly sin was that Olds omitted a fuel/water separator, purely for penny-pinching purposes. This was a standard item on essentially all other diesel engines. Water in diesel fuel was more common then, and removing water in diesel fuel is critical, as water corrodes the delicate high pressure diesel fuel pumps, injectors and other components of the system. Owners made the innocent mistake of adding anhydrous alcohol (dry gas) that is commonly used with gas engines to remove water from fuel, but in a diesel it dissolved fuel pump and other component seals.
Another weak spot was a stretchy timing chain: after 30-50K miles or so, the timing chain slack that would cause the injection pump to gradually fire later and later causing the pinging and detonation problems that exacerbated the “lifting” of the head and the gasket separation.
Another area that was a major concern were the glow plugs. The original pencil injectors were prone to failure and would leak sometimes contaminating the tips of the plugs. Also, when one or more glow plugs failed, owners would ruin starters and even engines with continual starting and/or lack of proper warm up. The original Stanadyne injection pumps were fitted with a plastic collar that was problem to failure. It was later retrofitted with a steel collar.
The initial version had flat tappets. These wore excessively quickly, as did the camshaft lobes. That required going to roller lifters and properly hardened cams. Crankshaft and connecting rod failures were not uncommon, quite likely as a consequence of water getting into the fuel raising combustion pressure drastically.
Compounding its woes, the diesel V8 was teamed with the new and notoriously weak THM-200 automatic transmission. The diesel 5.7 was the largest engine used with this unit, and failures were rampant. The combination of the two created huge failure rates, and even kept the diesel from being certified in California for some time. From that same NYT article:
In 1979 and early 1980, G.M. couldn’t sell its new diesels in California because test cars kept breaking down during state-run emissions tests. Thomas C. Austin, who directed the state’s Air Resources Board at the time, said that seven of G.M.’s nine test vehicles had transmission failures and all nine had engine problems. Mr. Austin, now a consultant to Consumers Against G.M., said the number of problems were ”extraordinary.”
And of course GM dealers had no experience with diesels, and were overwhelmed by angry customers. A number of customers were offered the option of swapping in a gas 350, and it was not uncommon to see an Olds with the Diesel badge on the road without the tell-tale noise and sooty exhaust.
Meanwhile, use of the Olds diesel engine soon spread across the whole GM family, starting in 1979 with Cadillac. It even became the standard engine on the new 1980 Seville, GM’s most expensive passenger car. So much for “The Standard of the World”.
Apart from all of the Olds diesel’s obvious reliability shortcomings, there’s also some questions that haven’t been asked about its performance, efficiency and actual impact to GM’s CAFE numbers.
A 1978 Olds 88 with the 5.7 diesel showed the following percentage improvement over the various gas engine versions:
3.8L V6: 20% 260 V8: 14% 350 V8: 26% 403 V8: 50%
Given that the diesel’s performance and 15 second 0-60 time was roughly comparable to the V6 and 260 V8, improvements of 20% and 14% seem pretty small, considering its higher noise, odors and soot, and most of all its extra cost of some $700-$800, which amounted to more than 10% of an 88’s purchase price.
In 1985, using the EPA’s adjusted numbers for an 88 (18 city/27 highway/21 combined), the 5.7 L diesel had only a 17% improved combined number than the Olds 307 V8 (15/22/18), which also had considerably better performance than the 5.7 L diesel.
As a point of comparison, the VW diesel Rabbit’s EPA numbers were 41% higher than the same size gas engine, and the Mercedes’ 300SD’s numbers were 47% higher than the 380SE.
Not only does it appear that the Olds diesel was not as efficient as the other diesels on the market, it also lagged in power output. The 120hp version of the 5.7 V8 made .34 hp/ci; the 1980-up 105hp version made .30 hp/ci. The 4,3 V6 made .33 hp/ci. Yet the Mercedes non-turbo 4 and 5 cylinders made .48 hp/ci, and the Peugeot .49, and the VW even made .50.
Not only was the Olds diesel underdeveloped in terms of reliability, but also in terms of performance and efficiency.
The 5.7 V8 also made its way under the hood of Chevy and GMC 1/2 ton pickups, with a 125 hp rating. The tow ratings were reduced, which strongly suggests that GM was not very confident about its abilities to handle a heavy load.
In 1979, the very short-lived LF7 260 cubic inch (4.3 L) V8 diesel joined the party. It was essentially the same as the 5.7, but with smaller bores, and made a paltry 90 hp. It was quickly gone after its introductory year. (Note: the EPA numbers on these ads are the old unadjusted numbers, significantly higher than the adjusted ones used in more recent years)
Then in 1982, after the 5.7 V8 was already becoming well known for its deadly ways, Olds released the new 4.3 L V6 diesel. Essentially a 5.7 minus two cylinders, its head bolt count was increased to avoid the V8’s issues. In fact, it seems to have been a mostly satisfactory engine; it just took Olds a couple of more years to get there. The V6 was made in both RWD and transverse FWD applications, and made 85 hp, due to tightening emission standards. The 5.7 LF9 also had its power reduced from 120 to 105 hp in its later years.
Similarly to the 5.7 diesel V8, comparing the 4.3 V6 diesels EPA numbers shows only a very modest 8% improvement over the 2.5 L “Iron Duke” gas four, which had comparable output, but was of course significantly cheaper to buy.
Much like when GM wouldn’t kill the Corvair in its last years to spite its critics, Olds kept making its diesels long after the bloom had turned to a nasty stink. The LS2 version of the 4.3 V6 came out in 1985, with aluminum heads, specifically for the new FWD C platform cars (Olds 98, Buick Electra, and Cadillac DeVille and Fleetwood). How many were actually sold is another question. It was another one-year only engine, and undoubtedly finding one now, or then, would be a genuine unicorn. It created “The most underpowered Cadillac since WW2“.
Even a V5 version was contemplated, as confirmed by this prototype at the R.E. Olds Museum, and written up here. It was presumably intended for the N-Body cars. A four cylinder is also mentioned in some articles from the time.
At the end of the 1985 MY, the glow plugs on the Olds diesels were pulled, ending not only one of the worst chapters of GM’s deadly decade of the 1980’s, but also playing a huge role in killing the diesel boom that had infected America. That had resulted in diesels showing up in all sorts of cars, including a BMW diesel engine in Lincolns. Compounding this rapid death was the fact that diesel fuel had become more expensive than gasoline, and meanwhile gas engines were improving their efficiency.
No need to beat a dead horse any longer. Let’s just say that class action lawsuits of such epic proportions forced the FTC to step in and broker an arbitration deal through the Better Business Bureau, which resulted in payments up to 80% of the cost of a replacement engine, presumably a gas one if the customer wisely demanded that. But buyers still mostly got stung, as resale values plummeted, and nobody had any interest in keeping them going, except for a few die-hard fans.
A thought that I have sometimes pondered: What if the Olds diesel had turned out to be a great engine? What if it had been turbocharged, and put out a healthy 200+ hp along with massive torque? The EPA numbers wouldn’t have changed, but it could have been sold on as a performance engine, more powerful than the emasculated gas V8s of the time, a viable replacement for the big blocks of yore. Would it have ushered in a golden era of big American diesels? A counterpart to the performance era of the late ’60s?
On second thought, never mind. Even my imagination has limits.
Note: a rerun of an older post.
Related CC reading:
All of GM’s Deadly Sins are accessible here
1985 Cadillac De Ville 4.3 V-6 Diesel: The Most Underpowered Cadillac Since Before WW2 by Aaron Severson
Vintage R&T Reviews: 1978 Oldsmobile 88 and 98 Diesels – A Decent Start, But Some Questions by PN
Vintage Review: 1978 Cadillac Seville Diesel – Puffing And Chugging To Deadly Sin Status by GN
The Tortured Tale of the GMC Toro-Flow Diesel Engine: Truck-Stop Triumph or Deadly Sin? by Robert Bray
Great article. Thank you.
As in the past, I will defend (as much as a person can defend) the 5.7 diesel to a certain point. Yes, that late 1977 to late 1980 engines were a failure. But from 1981 to the end, they were much better due to the changes pointed out in this article. But let’s step away from that side of things and look at this from a different view. I grew up on a farm in the Midwest. Many farmers purchased these GM diesels and loved them. My parents didn’t get one surprisingly, but we knew others who did (even some of the 78, 79 and 80’s engines) and they drove the wheels off them. I’ve personally seen them with well over 300,000 miles with the original engine and trans. This all boiled down to just how they were taken care of and who/how they were driven. Now contrast that to a couple who lived in town that we knew and they got a 1981. Yes, they had all kinds of issues.
What we learned over the years and was confirmed once I began working at a Buick and Cadillac dealership in the late 80’s, was that too many buyers lived in the city and didn’t understand the diesel. They would not plug them in. They would start them and drive short distances and shut them off. They listened to sales people who knew little about them and didn’t do the proper maintenance. Basically, they were driving them just like the similar gas powered GM cars they had before. Now add all that to the defects that engine had and it was disaster after disaster. But for those farmers who understood diesel and the sales people who drove a ton of miles, these were good cars. And over the years, I’ve owned a few (purchased used) and I never had one issue even though they were all high miles cars. To be exact, I’ve owned a 1980 Buick Park Avenue, 1981 Olds 98, 1982 Cadillac Deville and a 1983 Buick Century (v6) with the diesels and really liked them. And I could get over 30 MPG on the steady highway driving.
If only they would have waited till the 1981 changes to bring them out and improve them from there, then maybe this story would have turned out much differently.
In other words, buyers were really at fault for using their new Delta 88 or LeSabre diesel cars as cars, rather than as high-strung exotics that could only be driven under the light of a full moon after a priestly blessing. Sure, that makes sense.
When the LF9 diesel came out in 1977, Oldsmobile project engineer Paul Mutty declared, “We took the attitude that the operator of this vehicle knows how to drive—that’s all. It’s important to him that he doesn’t have to lift the hood to do something mechanical.” Perhaps that was unrealistic with ’70s diesel technology, but that was what GM told buyers to expect.
Even the Oldsmobile engineers who worked on the LF9 project said dealer service departments didn’t know what to with the diesel. When E.F Lindsley of Popular Science tested an Oldsmobile diesel, he said, “I was unable to find a single Oldsmobile garage with the proper CD oil made for use in diesel engines. I had to search it out at an International truck dealer and take the oil to the Olds agency to get it changed.” So, doing the proper maintenance this engine needed required owners to know more about diesel maintenance than most of the techs working at GM dealerships and either guide the dealer in what to do, go to a specialized diesel mechanic, or do the work themselves.
These were not reasonable expectations for a new general-use passenger car, or for a vehicle that a reasonable person would feel was being sold as a general-use passenger car. It’s like serving toxic fugu fish at McDonald’s and saying, “Sure, some people got poisoned, but that’s because they didn’t ensure that the fish was prepared properly.”
Geesh, chill Aaron.
First, what I said about the city folks is true. But I didn’t say that is was how it should have been. My point was simply that those (farmers, etc) who understood the diesel better had better luck with them.
Second, and I know this from first hand experience, is that sales people were “selling” the diesel as a “lower maintenance” vehicle and this sold buyers on it. But when that wasn’t the case, it was the buyers who got bitten. So it sounds like we kind of agree there.
Lastly, your last paragraph is acting as if I personally made those decisions and that I am defending them. I’m not. Again, read my comment without your obvious bias and you should see exactly what I was saying. Just to be clear: I admitted that the 77-80 diesels were not good. That the 81-85 were much improved. That they should have brought it out with the 81 changes and “improved” from there. That those who truly understood the quirks of a diesel had mostly good luck with them. AND, that I personally had good luck with them.
I’ll bet that the farmers who bought the diesels were familiar with running diesel engines and added a water separator filter as soon as they bought the car. That would be cheap and easy (GM should have had it standard) and would avoid all sorts of problems.
I think the NIH Syndrome was the original source of trouble. So many experienced Diesel engine makers back then! Mercedes had even had a Diesel powered sedan back in the 1930s. And why not ask Deutz in Cologne? Making quite nice and durable V6s, V8s, V10s and V12s back in mid 70s, still running in European army trucks
I was fourteen years old when these engines came out. I remember the two gas crises well (which we didn’t have in Canada) and GM’s response to it, namely the diesel. The first generation was awful, and we did quite a few engine swaps, usually to a gas 350.
I wanted so much to love that GM was doing, but Oldsmobile Diesel was such a disaster that even I, a GM fan, admitted the engines were junk. This was in total contrast to the VW and MB diesels, which lasted pretty much forever.
I sometimes wonder what would have happened if GM developed a truly modern engine (for the time.) An OHC V-6 and V-8 could have improved GM’s CAFE numbers without the unreliability of a diesel.
They were not absolute junk, when properly maintained they would do a nice enough job. But for the average buyer, used to the bulletproof V8’s they had before, that would run forever, these engines were simply to delicate. Something a diesel V8 should never be….
I owned one, somewhere around 1985, a 1978 Olds, and yes, the fuelpump failed in a horrible way, with very nice thick white smoke when starting and accelerating. So it got swapped for standard 305 small block. Would lobe to own it now, and keepnthatndiesel running, just because the rarity.
I know Case tractor hired a German diesel engineering consultant in the 1950s. I’m guessing GM was too proud to do that. Instead they re-invented the wheel. And as you said, they had Isuzu under the tent but again, NIH attitude.
They clearly didn’t understand or were too late in understanding the shock waves of higher BMEP combustion and other idiosyncrasies. Otherwise it looks like typical bean counter dictates, not enough head bolts, no water separator. The engineers complain but the bean counters have more sway in the board room. After the fact the same bean counters blame the engineers for “not pushing back hard enough”.
Good synopsis of all the Olds diesel issues. Regarding Detroit Diesel, one story I heard was that Oldsmobile actually did consult with Detroit on the 5.7, but it was late in the program’s development after much of the design had been ‘locked in’. One issue that the Detroit people supposedly pointed out was that Oldsmobile was not testing the 5.7L diesel properly on the dynamometer (diesels spend more time at full throttle than gasoline engines typically do) and their testing was likely not uncovering potential problems. That certainly sounds plausible! The 4.3L diesel didn’t seem to have any issues at all, other than people were scared to buy them.
I had worked on a few 5.7L diesels back in the day, and knew a few owners. One friend had one in a very nice ’81 Toronado, which was a reliable if slow car. I would agree that by 1981 (DX block) GM had all the issues ironed out. The 5.7L diesel was not hard to work on.
Despite the Olds 5.7L diesel many issues, I would have to give the award for the worst diesel of all time to the Ford/International 6.0L Powerstroke/VT365. Constant problems, a penchant for spectacular catastrophic mechanical failures, and usually very difficult to repair. Ford pickups equipped with the 6.0L Powerstroke had an emblem on the door which we referred to as the ‘Chrome Badge of Death’.
Final nail in the coffin for Navistar International.
Nice article – it filled in a few gaps in my knowledge of why Olds didn’t get with DD for development.
I bought a 1981 Cutlass Supreme Diesel – it was the only one on the lot and the bad reputation had just begun circulating. The dealer wanted it gone so I got a huge discount plus GM had a $750 factory rebate.
With the updated block I had zero problems before selling it to my sister when I had to go overseas. She kept it for a number of years and her kids learned to drive in it. Other than it being “gutless” WRT acceleration, she had no major mechanical problems.
To have 8 head bolts on an engine that was 8.5 to 1 that got changed to 22.5 to 1 doesn’t take much to know why it failed. Nobody, i assume, was told to check the head bolts often. That said some of these readers testify to more than 300k miles on the last of their production. Probably cold weather climates and checking the head bolts made a difference. And further, the engine was, as reported here, actually eventually fixed.
Oldsmobile increased the size of the head bolts for added strength for the diesel. Something the article failed to mention. With close to half a dozen Olds diesels that I regularly drive, I’ve never once had a head gasket failure, or even any failures.
I’m curious about the 350 diesel being standard equipment on the 1980 Seville. Please tell me Cadillac didn’t do that thinking it would bring in would-be Mercedes buyers.
I can’t find exact figures but it seems a sizable majority of ’80 Seville buyers choice the optional (at same cost) Cadillac 368 gasoline engine. (California cars got neither, they all had the Olds 350 gas engine, same one used in previous-generation Sevilles. The ’80 Seville showed in the advert above looks so much better without the two-tone paint and extra chrome trim emphasizing the weird bustleback. Not that it looks great without it either, just not as bad.
I think it was more that they were thinking it would bring up their CAFE numbers.
Yup. Only 36.8 percent of 1980 Sevilles (not quite 14.5K) had the diesel, even though it was technically standard.
Those were based on the big block Olds engine, made with a reduced bore to add strength. Bb Olds gas heads would bolt on with a slight enlargement of the bolt holes. I helped in a shop where we converted one back to gas, diesel bottom end, gas heads, cam and intake. It ran well and being registered as a diesel, no annual CA smog check requirements.
The diesel was based on the low deck small block. Two things came over from the tall deck big block. Those are the 1/2 inch head bolts (7/16″ on the small block) and the larger main bearing size (3″ verses 2 1/2″ for the small block). Big block heads would bolt on, the small block head bolt holes had to be reamed to the larger size.
I am one of the few that has an original Olds diesel car, with it’s original engine. At present the car has 230,000 miles on it. Over the years I’ve owned quite a few of them and one was the 260 V8 diesel and another the V6 in a FWD car. I’ve also changed my share of head gaskets too.
While head gaskets were a problem, Olds upsized the bolts to 1/2″ (BBO size) from the 7/16″ of the small block it was based on. If I recall, there were three improvements in head bolts over the run and for years there have been stronger alternatives in the aftermarket. The governor flex ring in the Roosa Master (became Stanadyne) injection pump was another problem. Any alcohol (from additives) introduced in the fuel would start chemically breaking down that ring. One it started disintegrating it would plug the pump outlet check valve and low power/stalling would occur. After the internal pump housing pressure would bleed off, it would start and run normal until the process repeated itself. An improved flex ring was developed and that was/is no longer a problem.
My aunt was the unfortunate recipient of the Olds diesel catastrophe. In her 77 Olds Delta, the crank broke at 40K miles, the dealership put that on her. 2nd engine failed after another 45K miles, the cam was wiped out. GM covered the engine, but got hit with $1200 to remove & replace. At just after 100K miles, the trans gave up the ghost & that was it, never again to buy American. A Honda buyer since the mid ’80s til her last one in ’12. Dealers are the worst representative of the brands. Worked for the Pentastar group for yrs, almost done with them.
I worked at a GMC full line truck dealership from 1978 to 1986.
The 5.7 diesel engine in the pickups were a disaster from day one.
Then the 6.2 diesels came along with the same problems, head gaskets, glow plugs, fuel pumps leaking.
The secondary fuel filter on the 6.2 diesel was ridiculous to service. You had to remove both fuel lines and unbolt the mounting bracket to remove the spin-on filter. Only thing I ever encountered that topped that is Moto Guzzi engines that had the spin-on oil filter inside the engine! Yes, look it up, you have to remove the oil pan to change the oil filter.
Luckily I worked mostly on medium duty trucks and heavy duty trucks.
Gotta love that sign saying $3.00 per customer. What might a sign say this summer if there was a fuel shortage?
Despite the complete negativity in this article there are many Olds diesel fans out there, including myself. By 1980-81 Olds had improved the diesel, those are really fine engines. It’s crazy to get 25 mpg in a big heavy luxury car, and at speed the diesel noise is missing, just silence. From my experience, a far worse deadly sin were the Buick v-6 and V-8 with the terrible lubrication systems. I’ve seen plenty of broken cranks, rods knocking, seized engine, no or low oil pressure. Sometimes the oil pump loses prime and won’t work if the car is idle for a few weeks, the oil drains out of the pump. I’ve collected a few Buicks that went in for a oil and filter change, the pump loses prime, and no oil pressure. So the junk yard is called to haul them away. The amazing thing is Buick had this design from 1961 all the way to the mid 80’s, a 25 year run of disaster, and few critics have went after the Buick design, like they did the Olds Diesel. Yet Olds rapidly improved their engine in just a couple of years.
Duane I’m curious if the Buick 350 was among those that had issues. I ask because we owned a 1980 Park Avenue with that Buick engine and had zero issues. I bought it with maybe 90-95k on it, I changed the timing set and I kept up with the maintenance. That car was run with a very small amount of oil on the freeway one time when the oil pressure sensor broke and the oil leaked out, and it was overheated on another occasion when the radiator developed a crack. Both times I was on the freeway and couldn’t get over to stop. That car ran until, at 170,000 miles the electrical gremlins took a hold. Now I had been warned about the 307 V8 that came in later years, but never heard anything about the 350. Im just curious! Currently the 425 in my 78 Cadillac is getting new head gaskets (leaked from sitting 7 years) a new intake manifold gasket and a carb rebuild. It only has 50,000 miles and once we cracked the engine, it shows! I’m hoping to run that one for a long time…unless you have any warnings regarding that one? Thanks
The Buick 350 was a solid engine. However it, like all the later Buick small (215-350) and big blocks (400-455) and the 90 degree (rear drive) V6 had a weakness. It was the aluminum front cover which housed the oil pump. The cover could become scored, leading to what Duane said. And if you took the oil pump apart, you’d better pack it with vaseline or light grease of it would never pick up prime.
The Caddy 425 is a good solid engine. It came from the 472/500. The 307 Olds engine you were warned about is another good solid engine. It’s one of the Olds small blocks.
Thanks for the info. You made me chuckle as I remembered installing that timing set. The mechanic helping me asked my wife for a jar of Vaseline, and we thought he was kidding! Nope, we packed that oil pump fill to the brim so that when we started it, the pressure built immediately. That was truly a remarkable car as before I bought it, the car had been stolen and was used in a police chase. To stop the criminal, they T-boned the car, but not until he’d led them in about a 20 mile high speed chase.
And thanks for the info about the 425. After this (unnecessary) refresh, I plan to drive it! My 31 year old daughter has asked that I leave it to her, and I said I would but that it may have a lot more miles on it!
As a die-hard fan of diesel power, it is both saddening and infuriating that GM did not draw from it’s many worldwide divisions to build a reliable diesel engine for the US car market. As mentioned in the article, Isuzu had a large line-up of well built dependable diesel engines in all sizes. The Detroit Diesel dealer in northern Ohio also sold Isuzu engines, primarily for industrial and marine applications. From the late 1970s through the mid 80s they did several hundred conversions using both 4 and 6 cylinder Isuzu diesels, installing these into step-van type delivery vehicles, with excellent results. Airstream, the RV manufacturer, also built several hundred Class A motorhomes using Isuzu 6 cylinder diesels. I had personal experience with these, all good. Please correct me if I am wrong, but did not Vauxhall, Opel, and Holden all have diesel engines for automobile usage in this same time frame? GM’s half-assed efforts in building the 5.7 liter engine (plus the VW emissions debacle) ruined the market for diesel passenger cars in this country, probably forever.