Oil filter housing leak fix how to (long)

[erniep]

I have been putting off fixing an engine oil leak coming from what appeared to be the oil filter housing on our '96 M44. Saw a number of write ups on various boards concerning o'ring and gasket failures, and stopped at the dealer for the o'rings and gasket in anticipation of finding the time to do it. I did it last weekend, absolutely no problems at all.

First I disconnected the battery. Then I removed the fresh air tube and air cleaner box and associated covers, and disconnected and set aside the MAF boot with MAF still attached to give me access to the alternator and then the alternator/power steering pump mounting bracket. Removing the two wires connected to the back of the alternator and then the two thru bolts holding it to its mounting bracket gave me access to the four bolts holding the mounting bracket. I did not remove the power steering pump, but I did remove the attaching nuts for the power steering pump reservoir and set the reservoir aside (I did not remove the hoses). Then I removed the six bolts holding the oil filter housing to the front cover and the oil pressure warning light sender wires. I pulled the housing out of the block, it lost very little oil. Of course it was oily there anyway so I didn't care. The gasket came off mostly in one piece, and the round adapter that has the two o'rings on it came out with the housing. Those o'rings were very brittle and flat where they seal against the housing and front cover. Definitely the source of the leak.

Here's where I could have done things a little differently. I should have removed the oil filter cover and oil filter before I loosened up the housing. Why? The inside of the housing where it bolts to the front cover needed to be cleaned, and although I intended to change the filter anyway, I did not want to get any cleaner or dirt onto the filter. The point is it's easier to remove the cap on the car than on the bench.

Before reassembly I cleaned up the remainder of the gasket from the block and housing, replaced the two o'rings on the round adapter, and cleaned up the area between the housing and the front cover using brake cleaner. Although I knew I would be changing the oil, I was careful not to get too much brake cleaner in the oil passages in the front cover. There's a couple of passages in the housing that I made sure were not obstructed.

Reassembly was the reverse of disassembly - I oiled the o'rings, put the adapter into the housing, then pushed the adapter/housing assembly into the front cover. The 6 bolts went back in, then the alternator/power steering pump mounting bracket, the alternator, and then the belt. I don't know how to make installation of the alternator any easier - it's a very tight fit, it took some patience and a plastic dead blow hammer to gently ease it into place. Reinstalling the power steering pump reservoir and air box and related parts was no problem. It fired right up after reconnecting the battery. Plus, all that work fixed the leak!

The hardest part of the whole job was relieving the pressure on the tensioner enough to remove the alternator belt. The Torx 50 hole in the tensioner needs to be a tad deeper in my opinion - I got it to retract, even managed to put a pin in the tensioner to keep it retracted for ease of reassembly. But a deeper hole would help prevent scratched knuckles and possibly a damaged Torx bolt.

It took me about 1 1/2 hours total, including the extra time to remove the oil filter on the bench vice using a couple of pieces of wood to protect the housing. Wrenches/sockets included 10mm (air box, power steering pump reservoir, oil filter housing, small wire on the rear of the alternator), 13 mm (alternator mount bolts, large wire on the rear of the alternator, battery cable), 15 or 16 mm (I can't remember) for the alternator thru-bolts, Torx 50 for the belt tensioner, a nail to pin the tensioner, a screwdriver for the MAF boot, and the oil filter cap wrench.

Hope this helps someone who needs to do this.