My youngest son had been driving an e34 535i since we got back from Germany. It was kind of a basket case, but he and I (mostly me) have been keeping it running pretty well. At least until last month anyway. He called me one night saying he needed a jump start, so I came to his aid and got him going again. While wrapping up the cables I thought the engine sounded a little funny, but I didn't give it much thought, and my son said something about a lot of steam coming from the tailpipe, but I chalked it up to a cool & humid evening, and we both started for home. My phone rang as I was pulling in the driveway; "Dad, I think I'm gonna need a tow; my car's overheating."
Then it dawned on me. Head gasket.
So we flat-towed it the mile or so home. The next day I pulled the dipstick, and milkshake.
It's repairable, but given the car's other problems (did I mention it was a basket case?) we decided to cut our losses. My oldest son took the car and is stealing some parts off of it for his e28 project.
The next weekend we test drove an e39 530i, and brought it home.
It wasn't without problems, but we're working through them. First on the list was massive vacuum leaks, so we replaced both intake boots. The ones that came out may well have been the originals; pretty hard, and large cracks in the bellows. Removing the DISA valve was part of the process of replacing the intake boots, but we ran into a snag with that when I found I couldn't get the valve out of the intake. Normally, you remove two screws and the wiring connector and it slides out, but this one moved out about 1/4" and stopped. Knowing what I do about that valve, I figured that the vane had separated from the body of the valve and was holding things up. I ended up using a thin allen wrench held by a Vise Grip to move the vane enough that the valve came out without further breakage. The biggest danger in the valve failing like that is the likelihood that the steel pin that holds the vane in place gets sucked into a cylinder, but thankfully the pin was sitting just inside the hole in the intake manifold.
The local dealer didn't have a replacement DISA on hand (they're kinda worthless that way), so I stuck the broken valve body in the intake just so it wouldn't have a gaping hole in the side of the intake manifold. I ordered a
repair/upgrade kit from German Auto Solutions, and the following weekend we got that installed. Very nicely engineered piece; uses aluminum in place of the original's plastic parts, and makes it far less prone to failure than the original.
I think there's still a bit of a vacuum leak somewhere; throttle response is a little weird when it's cold, but it runs very smoothly after it warms up a little. We got no service history with the car, and it's got around 180,000 miles on it, so we're starting to gather parts to do redo the cooling system. Getting at some of those parts is easier with the intake manifold off, so while we're in there we'll also replace the CCV system and any vacuum lines that are under the intake manifold. Also planning to replace the oil canister gasket, which is where the occasional drop of oil comes from under the car.
All in all it's a solid car, but just needs some maintenance catch-up done. I can't get over how nicely the thing drives, especially on the highway.