Replace Air Intake Rubber Boot on BMW M50 Engines (E34)

Rubber hoses and other parts, especially ones subjected to extreme temperatures or vibration, tend to loose their flexibility and crack or tear. Thus it's important to keep an eye on those on older cars. This time around I found cracks on the main air intake boot. A quick check on part availability on pelican parts revealed, that it's a comparatively cheap ($25) part, so I ordered it and once it arrive I headed to TechShop (http://www.techshop.ws/), where I usually do all my car repairs.

This work is relatively easy. You will need to take out air intake filter housing with air temperature sensor housing (attached to it) in order to get good access.

In order to gently remove air filter housing you'll need to get rid of front half of the alternator cooling hose. Gently remove locking pin from the top half of the pipe mount and then pull the front of the pipe up until it becomes loose. Leave the second half attached to the alternator, it's not getting in the way.

Detach air temperature sensor connector buy turning it about 90-120* counter clockwise and pulling it off. Loosen clamp holding rubber boot around air sensor housing. Loosen two nuts holding the air filter housing. One of the locations is hard to get to, so you might need one of these (pictured) small step click wrenches. Also remove auxiliary thermostat, attached to the air filter housing.

Once you verified that, nothing else is holding the filter box, start lifting it up while gently pulling the rubber intake boot off. It can be done by squeezing one side of the boot. If everything done right, the filter box should come out without any complications.

With air filter housing out, engine compartment should look like this. It's time to loosen the other end of the boot, remove couple of attached hoses and get rid of it. Loosen large clamp attaching the boot to the throttle control housing and then gently pull it off. There are two hoses attached to the bottom of it, so be careful. Pull those hose fittings out and completely remove the old torn part. Check out the cracks in one of the photos.

The rest of this job can be done pretty much by reversing the disassembly steps, but couple of words of caution. When attaching the hoses back to the bottom of the rubber boot, be careful to not brake the fittings as well as to not pull the hoses off of their fittings at the other end. Do not over-tighten the clamps around the boot at either end.

Using the same clamps, attach the boot at one end, insert air filter box while attaching the other end of the boot to it. Re-use the same steel clamps, which you took off in earlier steps, there is no need to get new ones. Reattach auxiliary thermostat and air temperature sensor connector. Don't forget the alternator air cooling hose from the first step and you should be done! Finished product should look like this.

Good luck and thanks for reading!