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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
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

Re: 320-most likely place for manifold leak?
Posted: Wed Oct 19, 2011 6:31 am
by rover-2000
Looking forward to it......
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
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

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

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