1995 BMW 740i Rear Manifold Cover Replacement
(Or how to turn a two-hour job into 10 minutes)
(just replace the cap, diaphragm and spring)

 

If you have ever replaced one of these things, you know what a knuckle-scraping frustrating job it is.
The last time I replaced mine was a year ago and I asked myself why I replaced the whole Manifold Cover instead of just replacing the cap, diaphragm and spring. So this time when it needed replacement, that is what I did. What a pleasant job after doing it the old way.

It turns out that the diaphragm is the only moving part in this assembly and the only part that wears out. Actually, it just gets dirty and no longer creates a tight seal.

The manifold cover is located on the top back of the engine next to the firewall. The symptom of a bad manifold cover is that you will get smoke blowing out of your exhaust when you first start the car and it will run roughly for a few seconds. This procedure will work for later model cars also. Not sure when the style changed from this 1995 model though.

Here's what you need to do:

1. Purchase a new manifold cover from your BMW dealer. They are about $50.00

2. Carefully pry the cap off of the new manifold cover. I used two screwdrivers at once to do this. You may be able to use one.
Go slowly. You will damage the new cover if not careful.

3. Pry the cap off of the old manifold cover. You do not need to remove the manifold cover from the engine.
You may need to remove one screw from the upper left of the manifold cover to get a screwdriver into the left side to pry the cap off.
Don't worry about breaking the old cap.
Also, remove the rubber hose at the upper left next to that screw. Just pull out and it will come off.

4. Snap the new cap in place onto the old manifold cover. Remember to insert the large spring first.
I did this by placing the bottom of the cap first, then inserted the spring, then snapped the top of the cap in place.
Re-install the screw and push the rubber hose back on.

That's it! 5 minutes to remove the cap from the new manifold, 5 minutes to remove the old cap from the old manifold.
and 30 seconds to snap the new cap onto the old manifold cover.

Pry off the cap from the new manifold cover.
(note: this is really the old cap but pretend it is the new one)
Part number for 1995 manifold cover is 11-61-7-501-562

Here is what the old diaphragm looks like inside of the cap . It gets dirty and does not seal properly.

Here is the cap removed from the manifold cover.

 

Rich Love
www.carnationsoftware.com
richlove@carnationsoftware.com