Freakin' expensive manifold!

Prutser · 21st July 2004, 23:02

I took the 1992 3.8l to the garage for the annual car safety inspection (APK) today and to my surprise it failed the test! Apparently the flexible joint in the first exhaust manifold (cylinders 1-3) took so much wear and tear over the last 12 years that it started leaking. As a result, the lambda probe further down the exhaust registers a high oxigen level (as fresh air now enters the exhaust through the faulty manifold) and responds by making the fuel much richer. This results in unburned fuel, which apparently causes the carbon monoxide level of the exhaust gas to go skyhigh (and way over the level tolerated by law).

Now replacing the leaking manifold seems the only option, but this thing turns out to be 1500 euro for the 3.8l (1300 euro for the 3.6l models)! That is excluding labour for replacing it.

Am I out of luck and do I face spending around 2k (manifold + labour) for a three-cylinder manifold piece, or do I have more options? I haven't searched the auction sites yet, but 3.8l M5's are rare in the Netherlands, so unused, 2nd hand manifolds that are in good condition must be even worse. Where do I start?

P.S.
The part's serial number is 11.621317080

cheers,
Erik

RandyZ · 21st July 2004, 23:37

How about repairing it - Can you show it to a good welder. He should be able to advise you if a repair can be made.

Prutser · 21st July 2004, 23:41

Quote:

Originally Posted by RandyZ

How about repairing it - Can you show it to a good welder. He should be able to advise you if a repair can be made.

It turns out that has already been done in the past. My mechanic looked at it and says it probably can't be welded twice.. (although he's biased of course

)

mblaster · 22nd July 2004, 03:39

Get that part to a good welder, there isn't any rule that says a part can only be welded once.

de Witt · 22nd July 2004, 05:53

Quote:

Originally Posted by mblaster

Get that part to a good welder, there isn't any rule that says a part can only be welded once.

Agreed. Your mechanic might be throwin some bs your way to get a nice expensive manifold in. Any welder who knows what he's doing wont hesitate to give it a try if they feel they can.

Prutser · 22nd July 2004, 21:31

I made some phone calls today with BMW specialists and as usual: the more opinions you ask, the more different stories you hear. One was about the flexible joint. According to one specialist it has no purpose other them making it more helpful for mechanics to fit the part (so he can twist it into place more easily). His suggestion was to just take a thick pipe, cover the entire joint and weld everything together. All you loose is some flexibility when putting the manifold in place.

Now it could be just me, but I always thought the main purpose of the joint was to allow the differently sized manifolds (the first is a lot longer than the second) expand and shrink as they heat up and cool off. Removing the flexible joint would cause tension on both manifolds and the cylinder head.

It sure is hard to find the real specialist.. but I'm sure he's out there somewhere!

Cyrus · 30th November 2004, 23:03

Hi,

Did you end up fixing this problem?

Danish-M · 1st December 2004, 05:41

Quote:

Originally Posted by Cyrus

Hi,

Did you end up fixing this problem?

Yeah, please let us know what you ended up doing here.
I got the same diagnosis on my M5 touring a couple of months ago, and I am looking at replacing the manifold, unless you can give me some advise on how to get around this problem in a cheaper way.

PLEASE HELP.

Cyrus · 1st December 2004, 08:34

I think the only solution is welding.
The biggest problem is finding a decent welder who is going to take his time looking at the problem and then do a good job.

As time goes by Im finding that more and more garages just dont give a **** anymore and dont put the heart ito the work even though you are paying them good money.

I have actually had some success with an idea of mine. I just happened to accidently venture into halfords and came accross the exhaust repair section.
Theyve got this metal sheet which is just wider than the flexi joint. So what Ive done is wrap the sheet around the joint. It comes with an attached big jubilee clip. This seems to be working so far but how long it will last I dont know.

Also, i think the flexi joint is there just to make fiting purposes easier. Why does only one of the manifolds have it?

raymondw · 1st December 2004, 08:42

Eric,

Try Jacob Ofenga in Dronrijp Friesland. He migh have some.

P.S: I would not repiar it, but replace it.