Oil Filter Housing Gasket Replacement w/O-rings, Belts, Idler Pulleys, Vac Hoses, Coolant Level Sensor Shabang.

Mileage 139,400

About 2 weeks ago I did some very overdue major maintenance. I should have done this the day I bought the car, but I didn't know exactly what needed to be done. Over the course of one Saturday and a Tuesday night I replaced the oil filter housing gasket and associated o-rings. I replaced the intake manifold hose to the ICV and intake boot. I put 2 new belts on with 2 new idler pulleys and one new idler pulley tensioner shock. (All shot) And just for the hell of it I ordered a new coolant overflow tank to match the new valve cover and fix the "Low coolant Level," warning sign every time I turn the car off.

Symptoms of these much needed repairs were a silver dollar size pool of oil on the front drivers side floor everyday. Not even dime, quarter, or 50-cent piece. Had to go with, "silver dollar." I was rounding the bases on gaskets and knew the oil filter housing was a major problem area.

The symptoms with the pulleys could be described as a lot of squeaking as I turned the wheel at a stand still. When parking or doing 3 point turns, the pressure from the P/S pump against the worn out bearings and shock would make the belt scream. Total jalopy noise.

The symptom for the coolant level sensor in the bottom of the reservoir was mainly that the OBC said I had low coolant level even after filling it up multiple times.

Day 1. Replace the oil filter gasket and o-rings, throw some new belts on and replace the coolant reservior and leveling switch. While the alternators out replace the ICV hose and clean that one more time. All good right? In and out in no time.....not exactly.

I removed the intake stuff and pulled the alternator off. Use a 8mm hex key or allen wrench to push the idler pulley down to release the belt. As you can see there's a large amount of build-up on pretty much everything.

I used this DIY I found. It's for a e39 I believe, but has the same overall principal/motor. It's a pretty decent DIY, but he does not do the all important o-rings that have been discussed a million times over, so DON'T forget the o-rings!

Oil Filter Housing DIY

The housing is held on with 6 13mm (M8) bolts. I removed those and the oil vanos line and pulled the whole thing out with the idler pulley and bracket still attached. I would have removed those guys first, but I have air tools, so I said fugh it. Besides the obviously fresh dripping oil you can see a ring of black starting right around the top of the filter housing. And what's that? Check out the split in the gasket. Dry, hardened, just not doing it's job.

A close up of the old gasket. I took the housing over to the "work bench" and took a look at it.

I noticed that the bushing for the tensioner shock was pretty blown out. The whole shock was crooked and pushing into the bracket. The pulleys also spun like a pair of 70s roller skate wheels.

I began to realize this job would not be finished today. I continued on removing the pulley and bracket with air tools. Here you can see the decimation of what was once the tensioner shock.

The part had been riding metal to metal for some time and was most certainly the cause of all the loud belt shrieks at low rpms. I put the two and two together and was thrilled that I had discovered the cause of those problems.

Back to the oil filter housing, I removed the two snap rings that hold the two quarter sized covers on the side. Inside one it almost looks like an oil thermostat. I know the euro motor has something like this, but I believe the housing are totally different. Either way it was interesting to see these holes that BMW plugged up for intentions never brought into fruition.

The snap rings pop out easy enough. The o-rings were dry and brittle. I did a little research on bfc to find what other people had used for the o-ring size. There is not a BMW part number for this. The only posibility BMW gives you is the replacement housing, which is $500+. About 499 dollars too many for just some o-rings.

This is the size and it worked like butter. 7/8"ID 1/16"OD 3/32" Thickness. I bought them at the hardware store. Before I put the caps back in I removed the oil pressure sensor and oil filter and gave the whole housing a much needed bath. Up until this point I hadn't removed the oil filter. I don't see a problem in keeping it in if you're not going to clean the housing.

Noticing the little plastic circulator on the gasket side of the housing, I was afraid to use any harsh degreaser. I went with my good friend Simple Green. Let that shit sit there for like a half hour or so and went to work on it with a SS wire brush. I hit some of the visible areas with some very fine scotch brite.

Wala. Clean filter Housing. I put the plugs back in with the new o-rings and set the whole assembly aside. I also replaced the old oil temp sensor for preventive measures. I then turned my attention to the coolant reservoir and new level sensor.

I was kinda bummed that the Behr unit was already a kind of yellowish color. Online it looks like an all white one exists but maybe that's what the $80 BMW unit gets you. It would have been nice if it matched the valve cover, but at this point I really have to wonder how I manage to have a girlfriend and obsess over white vs. off-white of an coolant reservoir at the same time.

White or off-white, it was a much needed improvement over the Incredible Hulk here. Replacing it with the radiator and shroud in place was no easy task. I wouldn't recommend it, but it can be done with a little swearing.

Here you can see three different whites living nicely together. Next up is the washer fluid tank, but the white cap is NLA?! What the f... black cap? Seriously? I don't know if I can live with a black cap on a white washer bottle, but we will see. We will see.

Now what....oh right one more item of Day 1 was the air induction tube for cooling the alternator. It had seen better days. I decided to undo what so many a previous owner had done with many different layers of tape.

I mean it's like $19? WTF? Just order a new one! Jesus...so much on this car is like, "uh well here's some tape, that should work." I know I sound a little laid back about my work style, but I mean come on, there's being resourceful and then there is just ghetto.

This would be ghetto. There was like 3 feet of duct tape and 9 feet of electrical tape. Not bad! The funniest part is how about just not running it? You really had to make sure that part was back in there?

So that's the end of Day 1. I cleaned up and made a list of all the parts I needed to finish the job.

I ordered some parts from RMeuropean and they arrived the next morning on Tuesday free of charge. I don't know if it's a California thing, but all the orders I've gotten from RM show up the next day even though I click free shipping through fedex ground. Shhh don't tell anyone.

Before putting the filter housing back on I attacked the vacuum hoses and ICV one more time. I had good results from cleaning the ICV before but it wasn't 100%. There was still some surging and idle drop from coasting in neutral. I noticed the hoses were hardened. Even if they weren't cracked there was no way they were creating a strong seal after being released from 15 years of a hose clamp and re-clamped again. I sprayed the ICV down with Intake cleaner while I had it out.

I replaced the TB gasket for good measure.

Underneath the manifold I also replaced the small plastic connector and o-ring. Every little bit counts with vacuum leaks.

With the ICV and hoses all in there I turned my attention back to the filter housing. As you can see the gasket fits in nicely.

I cleaned up the mating surface with some scotch brite and made sure there was nothing in the way. I added a little high temp RTV for good measure and bolted the housing back to the block. I torqued the 13mm bolts down to 20ftlbs. I think it is 16 or 18 but there is nothing in the Bentley about it.

I attached the vanos oil line with new washers and torqued that to 18ftlbs. The oil pressure sensor is 24ftlbs but I didn't have a 24mm Deepsocket so I used my mental torque wrench. Now I just have to clean everything else in the engine bay.

The rest of the bolts included in the pulleys, power steering bolts and alternator bolts were all around 18ftlbs I believe. The pulleys and brackets weren't hard to put on with the fan and shroud in the way.

I had to finangle the new belt around the fan and route it around the pulleys. I then removed and replaced the lower A/C belt. The bearings on there weren't as bad so I left them alone. They were actually pretty clean. I buttoned the intake back up and replaced the oil filter. I knew I had to add oil so I put about half a quart in before I started it up. I checked the oil after a quick start up and filled it appropriately. The last thing to do was add some coolant for the reservoir swap and burp the system.

Here's the, "I'm using OEM BMW coolant," shot. There is no reason why you would put the coolant bottle on the engine covers. I just think it's funny when you see pictures like this. Bleeding the system involves opening the bleeder screw and adding coolant until no more bubbles come out. Yeah, that's it.

So impression so far? Amazing. Like I said I should've done this the day I bought the car.

No more loud squeaks from the belts. Drivability has tightened up from the new belts and bearings. Before the idle would drop really low and the belts would squeak when traveling slow and turning the steering wheel.

I put down some white cardboard boxes and watched for oil leaks but they all just about cleared up after a couple days. There were a few areas to the rear of the car but they all appeared to be blow back from the major housing gasket leak.

The surging is about 98% gone at this point. The new vacuum hoses cleaned up the random drop and surge at idle that comes around maybe a couple times/week. I'm going to replace just about everything vacuum to see if it keep improving.

Also the coolant level low light no longer comes on after the ignition is turned off. So changing the sensor or bleeding the system fixed the problem there.

Overall all the improvements felt very accomplishing. There is nothing worse than doing a whole bunch of work on your car and having nothing change and the symptoms remain. Makes you never wanna pop the hood again. This was a pretty rewarding set of service. The only random thing is that the engine felt a little slower with the new pulleys. Maybe it's in my head or maybe they have to break in a couple hundred miles. All I know is that it feels nice and tight now, but before it was loose and revving all over the place. It's much better with the new bearings, but I just thought it was odd.