Project 46: Housing Crisis

Project 46 is an on-going series that demonstrates common fixes and preventative maintenance tips, as performed on our own E46 330Ci. Click here to read our introduction to the series, here for part two, and here for the last instalment.

The oil filter housing gasket is the second most common area to develop a leak on modern six cylinder BMWs, with the main culprit being the rocker cover gasket. If you think about how many times an engine will heat up and cool down over a period of a few years, it’s a lot of expanding and contracting for a little rubber housing gasket to endure. They become hard, thin, and brittle, and aren’t able to cope with the pressures of a modern oil system.

We knew there was a minor oil leak coming from the oil filter housing gasket when we picked the car up, but recently we’ve noticed more of a leak developing under the vehicle when it’s parked. With a bit of investigation, it was confirmed that the oil leak was coming from the oil filter housing, just as we had suspected. The first step was the jack the car up and remove the stone tray. It’s not absolutely necessary to do this, but you’ll probably have to clean the oil from the tray, and it also helps if you happen to drop a bolt. The fan and shroud needs to be removed, as do the belts and pulleys. (We’re often asked about the fan removal tool for the fan clutch -- we simply used a 32mm wrench and smacked the handle with a hammer to get the fan clutch off.) The complete airbox and alternator also need to be removed, and the power steering reservoir can be pushed aside. From here, only a few sensors and cables that need to be unplugged before the oil filter housing can be unbolted.


As everything was being put back together, we used a bottle of Autoglym’s Engine & Machine Cleaner to clean up the grease and grime that tends to find its way onto everything. The water-based biodegradable cleaner is safe to use on metals, rubbers, and plastics, meaning you can be a little carefree when spraying it under the bonnet. And unlike most aerosol degreasers, it’s not flammable, so there’s no danger with overspray getting onto a hot exhaust.

Although we didn’t do it this time around, we often have customers combine the job with installing our Cooling System Overhaul Kit so as not to double-up on labour. With the $5 gasket replaced on our 330Ci, everything was put back together in reverse order before the motor was topped up with a little more of Motul’s X-cess 5w40 oil. We still had half a litre left over from the Oil Change Kit we put through the car in the last Project 46 blog post. Now that the oil leak is sorted, we can get back to making the car ride and handle the way it should. Stay tuned for our next instalment.


New Mechanical Repairs:
Oil Filter Housing Gasket - $5
Total Cost of Repairs: $1580

New Non-Essentials:
Autoglym Engine & Machine Cleaner - $26
Total Cost of Additions: $62

Total Cost To Date: $1668

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