COAL Update: 100,000 Mile 2018 BMW 740e

2018 BMW 740e plug-in hybrid

Well, almost. Checking in with update #3, after purchase in September, 2020 at just under 11,000 miles; 39,000 miles in November 2021, and 72,000 miles in December, 2022. We are at 97,353 miles now.

We haven’t had any repairs or problems since the last update, and there was little to report at that time as well. This car has been quite trouble- and repair-free aside from the electric power steering rack being replaced under warranty right after my purchase. So there, I have probably jinxed it now. And as we all know, I am not in the “high risk” age or mileage range yet.

Aside from tires, wiper blades and oil changes, I have not incurred any other out of pocket maintenance or repair costs, besides what we delve into here. Still on the factory brake pads and rotors, which is unusual for a BMW at 100,000 miles in my experience. The regenerative braking of a hybrid figures into that, I’m sure.

If you read Kyree’s recent great post about his 2008 Lexus LS600h, maybe some dark mechanical days lurk around the corner for me if I keep the car long enough.

My car was built November 21, 2017 in Dingolfing, Germany, so the infotainment, hybrid system, air suspension, power seats, power side and rear sunshades, four-zone climate control, massaging front seats, pano roof with two power sunshades, soft close doors, power trunk lid, and other fiddly bits are now over six years old. A lot to go wrong, in other words.

But everything still works as intended, with no strange sounds, lights, leaks, or behaviors. I am well out of the 4-year, 50,000 mile bumper to bumper warranty coverage at this point. The various hybrid components were covered for 8 years or 80,000 miles. That’s over too, so I am on my own.

Being a plug-in hybrid, fuel mileage varies according to whether you are in town, plugging in or not, or on a highway trip where it’s mostly gasoline use. I continue to see a “long term” average of 42 mpg or so. I achieved 52.1 mpg on my last tank of mostly in-town driving. I have a Level 2 charger in my garage and always plug it in, so a lot of my in town miles are all electric, even with the small range this older model has. Although the gas tank barely holds 12 gallons, you don’t have to stop for gas often.

In looking over the Charging History on the BMW app on my phone, I hit about 270 kWh of charging each month by plugging in. The dash readout says I average 2.5 miles per kWh, so about 675 miles of electric driving per month from the grid. In addition to that, I have regenerative charging even when you don’t plug in.

My last oil change was 9/12/23 at 88,658, and I have driven 8,300 miles give or take since then, in three and a half months. So, about 2,300 miles, or 27% have been electric from the grid, and then some regenerative-powered miles on top of that. One-third of all my miles are electric on average, I’d say.

On a recent 200 mile interstate trip from the South Carolina coast back to my house, I filled up with gas at the start, which always automatically resets the “electric miles per tank” trip meter. I had 0% battery charge at the fill up. When I arrived home, I had covered 30 electric miles, to give you an idea of how regeneration still makes quite a contribution.

I usually select “EcoPro” mode every time I start the car (a button conveniently beside the shifter). This makes the gas engine shut off more often, and you start off in 2nd gear like an old Mercedes. Upshifts come quickly, and the car wants to get into 8th gear and stay there (it usually hits 4th gear by the time you cross a large intersection). The undersquare gas engine likes this, as it delivers its maximum torque down at 1,550 rpm. I find I get noticeably more miles per tank using EcoPro consistently.

2018 BMW 7 Series sport mode dash

For the opposite effect, you can pull the gearshift towards you to activate Sport mode, which keeps the gas engine on at all times, even when stopped at a light. You start off in 1st, gear upshifts are held quite a bit longer, and it tops out at 6th gear instead of 8th. The car is surprisingly peppy in this mode. It acts like a “normal” BMW in this setting.

I changed the oil shortly after the December 2022 post, at 77,500 miles. The next change oil message came up at 88,500 miles, and I used the same Castrol Edge Euro ACEA 0w30. The oil level was still snug up against “full” on the dash readout after 11,000 miles. The change interval varies, but is usually 9,500 to 11,500 miles in the time I have owned it. Right now, it is calling for a change at 99,300 or a 10,800 mile interval.

I also tackled a few other jobs, which were a little more involved than I planned. The work underneath the car was made possible (or less terrible) with the lift at the GOAL garage I wrote about.

BMW Transfer case

I changed the transfer case fluid, in a way. This is a “lifetime” fluid, and there is just a fill plug. If you want to change it, you have to siphon it out as best you can.

Low profile wrench

This lets you reach up behind the crossmember to the transfer case fill plug.


I had to buy a special tool to reach the 14mm hex fill plug (about $35 from FCP Euro), as there is a support crossmember in the way, preventing a regular socket and wrench from accessing the plug.

BMW transfer case

Here you can see the exhaust blocks removal of a bolt about 12 inches long, that goes through the crossmember, the transfer case, and into the transmission housing.


The “official” way to access the fill plug is to remove the crossmember, but that involves first dropping the exhaust, so I wasn’t about to get into all that on my own.

Various online videos from reputable sources (such as FCP Euro, which posts great DIY videos) stated because of the design of the transfer case, you probably can only remove about half of the 1L capacity at a time. Still, better than doing nothing at all. I got that out of it, maybe a bit more. Filling is pretty easy, just pump in the correct DTF1 fluid until it starts running back out.

Now that I have the correct “cheat” tool, I’ll do the partial change every now and then. The fluid that came out was solid black; the new Ravenol DTF1 is clear, with a slight yellow tint.

BMW Transmission pan

A ZF filter/pan kit, with new bolts, 8 liters of ATF and a fill plug included, was about half the cost of just a BMW filter/pan kit.


I changed the transmission fluid and filter, finally, after a couple of false starts. I gathered the needed replacement pan (the filter is an integral part of the plastic pan) and fluid. However, the fill plug is on the side of the transmission, very close to the transmission tunnel wall of the car. There is no room to use an 8mm hex socket wrench, or a traditional hex key either.

This same ZF 8 speed transmission is used in countless other cars, and in most instances (including the BMW 3 and 5 series), online videos shown you have more room to access the fill plug. I don’t know if this is because of the floorpan design of the 7 Series, or because I have the hybrid version of the transmission. The 111 horsepower electric motor is inside the transmission housing, and my filter pan is a different part number than a nonhybrid 7 Series with the ZF.

A low profile wrench

This lets you reach up between the floor pan and transmission to the fill plug. There is a hole at the bottom for a 3/8″ drive socket wrench for extra leverage.


After a lot of online searching, I finally found an aftermarket tool to reach this fill plug, for “all makes using ZF 8 speed hybrid transmissions”. Maybe it is an issue in other cars with this hybrid transmission as well, such as the 4xe Jeeps. About $50 plus shipping from, but the job is impossible without it.

BMW transmission fill plug wrench

With a 3/8 drive wrench attached for leverage.


BMW says the transmission fluid is “lifetime”, but ZF recommends fluid and filter changes every 60,000 miles. I felt OK with waiting until 88,500 miles with the mostly highway use my car sees, but I might lean towards doing it again in 70,000 miles or so, if I still have the car.

The old transmission fluid was dark like coffee, but not black, and it still smelled fine too. The new ZF-approved Liqui Moly transmission fluid (1/2 the price of the BMW labeled transmission fluid), like the DTF-1, was clear with a slight yellow tint. There was no debris or “slime” in the old pan. The plastic drain plug is one-time use; you have to replace the filter/pan if you drain the transmission.

You pump the fluid back in, until it runs out. You then run the car on a lift and shift slowly through the gears until the fluid reaches 90 degrees Celsius or so. I have a code reader which gives live data, including transmission temperature. After that, you remove the fill plug again (which is very close to the now hot exhaust). If fluid comes out, let the excess drain and then you’re done. If no fluid comes out, pump a little more in until it overflows. My car took about another half liter.

Low profile spark plug socket

BMW/Mini low profile on top, Mercedes-Benz low profile on bottom.


I also changed the spark plugs, which was easy once I bought the right socket. I had a “low profile” spark plug socket from working on former Mercedes-Benzes, but it would not go down the spark plug tube. I needed an “even lower” profile socket for recent BMW’s and Mini’s. It was a pretty slick tool with a strong magnet to hold the spark plug, about $11 on Amazon.

The old plugs looked pretty meh after 88,500 miles. The factory plugs were NGK’s from Japan, and the new BMW packaged plugs I bought from a BMW dealer were Champions from France. They are both iridium plugs, and BMW recommends changing them every sixth oil change, or about 60,000 miles. That seemed a little excessive to me, but now that I see the difference compared to new, maybe not.

An old and a new spark plug, side by side

New on the left, after 88,500 miles on the right.


I noticed the strap as well as the electrodes on the NGK’s were quite a but shorter than the Champions, which I assume is from wear? Anyone know if straps wear like that?

Engine of a BMW 740e

After removing the plastic engine cover, and the top sound blanket. As you can see, the small four cylinder engine is almost under the cowl, leaving a lot of room in the bay.


Access was very easy with the inline four cylinder engine, and they came out fine despite being past the recommended lifespan. The gas engine indeed seems to start quicker and quieter with the new plugs (it goes on and off a lot with the hybrid setup), though that may also be in my head.

Ignition coil

I was surprised to see the coils were made by “Eldor”, an Italian brand (Elettronica d’Orsenigo) I was not familiar with. A BMW tuning article I found says BMW used Bosch when they went to coil-on-plug ignitions in 2003, but then changed to Delphi (which my 2007 S550 had), and then Eldor in 2015. They are all pretty interchangeable but the Eldors put out more voltage, last longer, and are a popular replacement for the older coils.

The last two items were the engine air filter, and the cabin filters. The engine air filter was very difficult to find. After consulting a number of online sources, I finally ordered from a BMW dealer online……and THEY had to special order it from BMW. It is different from the other 7 Series, and also different from the 330e and 530e which use generally the same drivetrain.

I forgot to take pictures of this, but installing it required removing the plastic shroud above the radiator support, so that you could remove a metal reinforcement bracket, just to get the air cleaner open. It is a shame BMW (and other makes) don’t make their cars more serviceable.

The cabin filters (there are two) are easily available, and has many to choose from. I did order them from the dealer when I was ordering the engine air filter, and they were not much more than a name brand from

As cabin filters go, they are pretty easy to access. Like many cars, they are on the passenger side, behind the glovebox. The trim panel on the underside of the passenger dash drops down with a twist of two tabs, then the filter door has two torx screws. I am at the stage of life where I could not see what I was doing well, with or without reading glasses. It’s the perfect distance for blurriness either way.

The direction of the air seems counterintuitive; glad I paid attention to how the old ones came out. The airflow is towards the firewall, as opposed to towards the interior of the car. There are arrows printed on the filters, but I also took note of which side the debris was on for confirmation.

automotive clips

One indispensable thing for DIY servicing has been this box of replacement clips, about $20 for the whole box from Amazon. There are plastic clips and panels seemingly everywhere you have to remove for routine servicing and even checking the brake fluid. The BMW clips seem weak even though they are intended to be reusable, so having some substitutes on hand is a must.

The Pirelli Cinturato P7 tires (a “grand touring” tire) I put on at about 59,000 miles lasted longer than the prior Pirelli PZero (an Ultra High Performance or UHP tire) all season tires that were used up after 31,000 miles. At 97,000 miles, or after 38,000 miles of wear, they weren’t quite to the wear bars but I replaced them with the Yokohama ADVAN Sport A/S+, another “UHP” tire.

A new Yokohama Advan Sport AS tire

I’ve never had Yokohamas before, but there are good reviews on this particular tire, and I got a Black Friday online deal on them at Discount Tire, about $700 for a set of four out the door.

The other options bouncing around in my mind were the Kumho Majesty 9 Solus for about $600 out the door (a BMW driving friend at the garage likes his), or another set of Pirellis for $1200, so the Yokohamas seemed like a good compromise worth trying. So far, I like the way they ride and handle but they seem to be slightly noisier than the Pirellis.

I don’t know if the all wheel drive contributes to even tire wear, but the tires on this car wear very evenly, more so than about any other car I have had (both inside to outside across the tread face, and overall tread depth). At almost 100,000 miles, I have not had it aligned a single time, either.

After a couple of no-shows by other companies, I had a paintless dent removal person work on the dent in the hood. I wrote last year about some debris on the interstate causing this shallow dent, about 4 inches long, near the hood emblem. It wasn’t super noticeable to the casual observer, but it bugged the heck out of me.

I would post side by side “before and after” shots, but the dent was really hard to capture in a photo. The results were pretty amazing, though. $200, a lot of light hammering, and 45 minutes later, the aluminum hood positively looked like new.

A 2018 BMW 7 Series and a 1987 BMW 7 Series

That’s what 30 more years of age will do! Someone’s 1987 BMW L7 project car, behind the GOAL garage.


I’m keeping a close eye on three common BMW problems. First, the valve cover gasket is a common leak point (easy enough to fix).

Second, the water to oil intercooler which is part of the oil filter assembly on the driver side of the engine, will (a) hairline crack and result in an oil leak, or coolant leak, or both, or (b) the gasket between the housing and the engine will leak. Fortunately, they don’t typically fail in a way that causes a mixing of oil and coolant.

Third up is a difficult to see engine coolant hose connector under the intake manifold, which tends to leak.

So far, all three areas are bone dry on my car, and these issues tend to surface by 60,000 miles, if they happen at all. Extreme heat seems to be a contributing factor. Also, overtightening the oil filter over time can cause the housing to hairline crack (another reason to avoid quick oil change places).

Side of a 2018 BMW 740e

The Singapur Grey (Singapore Grey) paint, an “M” package only color, gets a lot of compliments from strangers, this view shows how it looks more silver-blue in direct sunlight.


I’m pretty relaxed in my driving style (Yacht Rock on SiriusXM is one of my favorite stations if that tells you anything) and probably reach lower underhood temps than a lot of BMW’s with four cylinder turbos. Perhaps the extra dead space under the hood of a four cylinder G11/G12 7 Series, which has room for a turbo V12 (as in the 760i, talk about some heat!), helps keep temperatures down.

I’m watching the new 2024 750e plug in hybrid with great interest. No way I would pay for one new ($115,000+), but if I can find a low mileage off-lease example in a few years at half (or less) of new MSRP, like I did with the 740e, it would be tempting. The 750e has an all electric range of 34 miles, twice the range of mine, out of a 14.4 kw battery (about 60% larger than the 740e).

The 750e weighs almost 1,000 pounds more than the already Rubenesque 740e (5,635 versus 4,740), however. Seems like the 750e might be past the point of diminishing returns, increasing the appetite for tires, as well as somewhat defeat the economy gains of the improved PHEV drivetrain.

That’s all to report for now, we’ll check back in another year!