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320-most likely place for manifold leak?

Posted: Tue Oct 18, 2011 4:44 pm
by rover-2000
Guys

We have had a new front exhaust section on the touring. The rear part was like new. (2 piece exhaust.)

There is still a leak though-fumes from the front of the car and a light "tapping" noise on acceleration.

Looking under the bonnet, the gasket heatshields are in poor condition, so I was thinking replace the manifold gaskets, but before I start, is there any likelihood of cracks in the manifold as there is with other cars?

Thanks.

Re: 320-most likely place for manifold leak?

Posted: Tue Oct 18, 2011 4:57 pm
by kitch
I had this problem on my 1987 320, new heatshield/manifold gaskets, studs and bolts and all was fine.

Re: 320-most likely place for manifold leak?

Posted: Tue Oct 18, 2011 5:20 pm
by AlpineCab
I replaced gaskets and studs on exhaust manifold and it cured the problem.

If in any doubt, and want to belt and braces it, then grab a manifild from zone or ebay. They're not expensive.

Re: 320-most likely place for manifold leak?

Posted: Tue Oct 18, 2011 5:30 pm
by daimlerman
Check carefully for broken exhaust studs,at the front and the back of the engine.The cast manifold has a habit of warping banana shaped and pulling the studs out....

Re: 320-most likely place for manifold leak?

Posted: Tue Oct 18, 2011 5:58 pm
by capri_rob
Good luck getting the nuts off without breaking the studs :eek:

You need to drench them in WD40 and penetrating oil for serveral days prior to attempting this, then get the engine hot, make sure you use a good quality tight fitting socket and then pray :cry:

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 6:31 am
by rover-2000
Looking forward to it...... 8O
Thanks guys.

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 7:46 am
by Barx325i
capri_rob wrote:Good luck getting the nuts off without breaking the studs :eek:

You need to drench them in WD40 and penetrating oil for serveral days prior to attempting this, then get the engine hot, make sure you use a good quality tight fitting socket and then pray :cry:
wd & heat ftw!

It does sound like you have a cracked manifold..

if you have a feel around when you start her up in the morning it may be obvious but newish cracks tend to hide until it's up to temp

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 9:24 am
by Brianmoooore
Whatever manifold you put back on, check that it is flat with a straight edge across the face. Get it ground flat if it isn't.

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 11:08 am
by rover-2000
I'm starting to wonder whether to get a known good manifold and just swap it anyway. The car needs to be roadworthy, so I can't afford to be stuck half way through the job.....

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 11:27 am
by capri_rob
Probably the easiest way - you should be able to get a 320i standard manifold for next to nothing, get a machine shop to check its flat and you're halfway there - as already noted the "interesting" bit will be getting the old one off :eek:

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 11:33 am
by rover-2000
Great-so has anyone got a standard 320 exhaust manifold to sell, preferably cheap! ?

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 1:04 pm
by capri_rob

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 1:42 pm
by rover-2000
Thanks Rob ! I assume they are all the same? (It's even off the same year and model as ours!)

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 3:48 pm
by Barx325i
I'm sure there are two types, but I don't remember now what the differences are.

worth noting the one up there has at least 1 stud missing though..

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 7:04 pm
by Brianmoooore
Facelift RH drive 2.0 and 2.5 manifolds are all the same.

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 7:17 pm
by Barx325i
sure the 2.0 & 2.5 use the same log but were there not two types of that manifold? I'm sure I read somewhere there were..

Re: 320-most likely place for manifold leak?

Posted: Wed Oct 19, 2011 8:41 pm
by ucpsale
Is the end stud (back of engine) broken or loose that would cause the sound you can hear, i would start with new gaskets and studs plus nuts. Like others have said plenty of spray oil and a good hot engine. Good luck

Re: 320-most likely place for manifold leak?

Posted: Thu Oct 20, 2011 8:23 am
by djsimmy
mine was doing this had 3 snapped studs..

had manifold taken off and put back on my a mate he drilled out the snapped bolts

all was fine then about 2 weeks ago my exhaust was blowing again really bad soundedl ike a tractor this time the bolts have snapped on the down pipe