The Head Gaskets Strike Back

Just when I thought I had ridded myself of head gasket problems. But I clearly forgot that BMW cooling system engineers in the mid-90s were a bunch of sick sadistic bastards whose sole mission was to inflict pain on future owners by designing cooling systems with plastic parts that failed 100% of the time. The only question with these systems is when and how much $ will it cost to fix (water pump? rad? head gasket? all of the above?). Thus, it really should have come as no surprise when the new race car a 1994 BMW had a possibly blown head gasket after overheating at its last race. The car also traveled on an open trailer across the midwest in early-February with water in the cooling system. This is also not good for aluminum heads - Mr Science says "water expands as it freezes."

We first pulled the spark plugs and coilpacks. It was immediately clear there was a problem. The frost lugs in the head between the spark plugs holes had all popped. Ruh roh, Raggy! Well, lest check compression. These numbers were mostly good in the upper 180-200 range. Ok, so the bottom end and valves are good. Leakdown test was a different story. Front cylinders had 40-60% leakdown and you cold actually see the leaks bubbling if you looked through the frost plug holes. $h*t! Here we go again. This time though there are twice as many heads, twice as many timing chains and way less room to operate.

We let the idea of doing both head gaskets settle in before we got started. Thankfully we found a Bentley manual online to help out and dcided that TM, Dave and I would just get started last Saturday. The passenger side is fairly accessible, so we started there. There were lots of wires to marks so TM went to get beer and masking tape. Both necessities for this particular job. Everything came off pretty easily (nice CA car bolts w/o rust). The intake mani was a bit of a task but TM and Dave handled it in pretty good time. Dave also started disassembling the water pump. Unfortunately, to get at some of the wires we had to remove the oil filter housing (huge pain) and the alternator, not bad once we got it unbolted. With the intake and exhaust mani removed and out of the way, we set to the task of removing the vavle and timing gear covers. This again went pretty smooth and no bolts were dropped into the oil pan or anything like that. We then got the timing gear removed and chain tied off.



Then came the fun part...removing the head itself. The head bolts are hard to get to and hard to see. First one came off all right but the second at the back was trickier. I almost poo'd myself when I got the special BMW torx wrench to take off the next bolt and it just sort of slipped. I thought I had stripped it - a disaster! TM and I exchanged one of those "oh no, please tell me that did not just happpen looks." I went in for closer inspection and it turned out the wrench had gotten wedged and just felt like it was on the bolt - wheeeeew. Got it on right and it turned as nice as could be. Go the other bolts out and were ready to get the head off. It came off with a little wiggling to clear the exhaust mani! Mission partly accomlished.


One head off

The head gasket clearly went on the 2nd cylinder, but inspection of the head didn't reveal any cracks. So, could be worse. At this point we were out of light and getting a little tired so we called it a day. Not bad for 8 hours work.

Sunday I had to work so TM and Dave were hoping to get going on head #2. This one is far trickier because the exhaust mani is unreachable because of all the steering and brake related items on that side of the engine bay. Mother Nature decided that was too easy though and gave us a foot and a half of snow Sunday, no head gasket tasks accomplished...Monday, was a new day though. And while I was working from home because the M3s 10 inches of ground clearance was severly lacking, TM went back to work with the Zen Master to get head #2 off. Like I said, this is not a meager task or even the same as repeating the task on head #1. Thankfully we've learned a few things from last years fun and head #1. Since we couldn't get the exhaust mani off, just take out the whole head with it still attached. Not sure on the details, but a few hours later I saw this and TM's message "success!" appear on my iPhone. Nice work TM and Zen Master!


You can see all the stuff in the way on the driver's side. Very tricky to work on.

I inquired if the head was still in good shape afterward, and unfortunately we weren't so lucky on head #2. As you can see, there is a big a$$ crack. I'm afraid we are going to have to put that one out of its (and our) misery. No big deal, we have 31 days until we depart for Road America and race one of the 2011 campaign.


Click on the pic for a better view of the crack

More on the misery to follow...at some point we have to figure out how to put it back together... Also, if you have a 1992-2004 bmw consider upgrading the cooling system, like right now. Don't say I didn't show you the consequences.