CC DIY: 2004 Buick Le Sabre – GM 3800 Series II Updates

The GM 3800 engine, which came in roughly 25 million cars, in three versions. This is Version II, as one can see, and it had a few shortcomings which could cause slight damage or serious damage depending on luck probably.

So here is everything spread out on my kitchen floor that I will try to get into the car in one day. I have never worked on a GM 3800 much less any GM engine, unlike Fords, so I expect to take a little more time than book in doing the work. Fortunately, with You Tube, there are plenty of good videos showing how to do it in a LeSabre and for many other GM cars.

First task is to remove the gravel guard with all the fasteners underneath in order to get to the radiator drain. Start time 12:00 noon.

Then carefully place some aluminum foil to divert the coolant away from the car.

Remove the three bolts holding the alternator and remove from the car.

With the alternator out of the way you can pry off the heater hoses. Good idea to replace those now older O-rings. I went to the local dealer to buy some and despite 25 million 3800 engines they didn’t have a set. The closet was in Reno, Nevada. Never mind and got them off Amazon (argh) in 3 days.

Moving on one now removes the idler assembly which I believe is also three bolts. With it out you can see those troublesome plastic elbows that can crack and leak. The actual joint were Ok on mine but one did crack on the end.

Next comes the water pump. First you need to remove the pulley. Once that is out of the way comes the water pump bolts of which a few are into the water jacket. Knowing that I placed aluminum foil so coolant didn’t hit the sensors below and cause trouble. Obviously one should use a sealant on all the bolts that go back into the water pump after the bolts are cleaned of the old sealant. Bolt cleaning alone took me an hour to get these clean as well as intake bolts. Another half hour was spent cleaning off all gasket material from the mounting face for the new water pump. Water pumps are easy.

On the passenger side it is time to disconnect a bunch of stuff. I studied up on this since I had never done one before and needed to make sure nothing was missed. Here three spark plug wires and a couple of sensors need to be moved out of the way. That also goes for the fuel injector connectors all around. The fuel rail is held on by two nuts each side so easy to deal with.

On the driver’s side you need to disconnect the throttle cables. Easy. There is a bracket with conduit attached that has to be disconnected and then the bracket moved out of the way. One bolt and one hidden 8mm nut buried away. Of course the 8mm nut, which was difficult to get fingers on, managed to drop down below (argh).

Sensors on top of the throttle body. What happens here is that the throttle body needs to be removed from the car to make room. Of course there is another nut underneath that connects to a bracket that the throttle body is attached to. Easier to get to compared to the other side.

Ok, so I am now ready to remove all the upper intake bolts. After that you lift the fuel rail off and direct to the back side of the engine, gently of course, to position out of the way. Then the wire harness that crossed over the upper intake needs to be lifted up so you can slightly lift the intake and slide it out from under.

Here you can see what the upper intake gasket looks like. Remove it and then take out the bolts for the lower intake. There are two bolts hidden in two of the corners that you need to know about. Those two were swimming in oil. The lower intake looked worse in person than it does here. Once that is out you can see the original GM plastic lower intake gasket which apparently doesn’t play well, over time, with Dexos so they say. An engine could get a leak and not know it until too late.

The lower intake was filthy and when I work on my cars everything must be as clean as possible before it goes back on. Getting this cleaned and then dried took about 1 1/2 hours start to finish.

As the lower intake was drying in the sun I placed the new steel gaskets and end seals in. Don’t forget the silicon sealant in the four corners to prevent vacuum leaks.

Lower intake back in place and torqued to specs.

With the lower intake in it is time to remove the small EGR pipe seen here. The major issue with this is that the air gap between the metal pipe and the plastic intake isn’t enough to keep the plastic from hardening and then cracking. On either side of the hole in the intake is a water passage and you can see two holes on either side of the EGR orifice. When they crack then water into the engine again if you are unlucky. So the newer upper intake assembly, I bought some years ago, has a narrower pipe and the intake has a protective metal sleeve inside as added protection. Also has the metal elbows to replace the plastic ones earlier.

However, Houston we have a problem. See what I see and both of the newly supplied replacements were the same size. Apparently pre-99 intakes used a pipe with a 0.750″ diameter while after used 0.625″ (ARGH!!!!!!). Just you know what great and nothing I can do about it. Not sold separately not that I would wait and leave the car as is.  The car must get back together as it is needed a week later. I showed Tom, on the USS Hornet, and asked if he could put it on the lathe and cut it down to the correct diameter and he said yes. So it will be done at a later time. Now my decision was which upper intake to use for now. The old one had 0.1875″ clearance around the original pipe while the newer upper would have only 0.125″ clearance. So I went with the larger clearance for now.

With the above decision made I put the thermostat housing, with new thermostat back in. Now you need to lift that harness out of the way to slide the upper intake in from the right. Then it is a matter of torquing down to specs in two stages and then replacing the fuel rail after new O-rings, replacing brackets, sensors and assorted cables and wires. This now goes really fast since I have been through it once already.

On passenger side you can see the new water pump, new idler assembly, alternator and new belt in place. You can also see one of those metal elbow replacements. Time of finish 9:30 PM and I was beat and sore from all the leaning over not to mention starving. Nonetheless, it was done. I’m not concerned about the EGR tube as I know I could get the upper intake out now in under 20 minutes and have it all back together in one hour.  Unfortunate that the Series III aluminum upper intake does not transfer directly over to a Series II. Anyway the car needed to be done as it is the long distance car and was needed to travel from the Bay Area to Valencia (Six Flags for wife and son) the following weekend. The engine ran smooth as silk for the almost 700 mile round trip down US 5 and then up CA 99 to visit family and then back to the Bay Area. This 2004 3800 II now has just over 63,000 miles.