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m78 · Posted: Sun Oct 24, 2010 11:02 am Post subject: what is a "head pipe"?

is that the header?

or the pipe connected to the header?
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Lachssilber Metallic 203 1988 325i sedan with 200,xxx miles

Top Speed 220 km/h

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85-325e · Joined: 30 Jun 2002 Posts: 4712 Location: Southampton, NY

I would think it's the header... The exhaust pipes coming from the exhaust ports on the head to the catalytic converter...
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Cosmo - 1985 BMW 325e, Single Owner, 265,000+ ORIGINAL miles and still going strong! But now on the East Coast and the salt air corrosion is eating my beautiful car alive... Sad

m78 · Posted: Sun Oct 24, 2010 1:58 pm Post subject:

I would think so too.

I've been told by a local wrench that I have a crack in the head pipe.

Is it common for the header to crack over time?
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Lachssilber Metallic 203 1988 325i sedan with 200,xxx miles

Top Speed 220 km/h

(OO=00=OO)

85-325e · Joined: 30 Jun 2002 Posts: 4712 Location: Southampton, NY

There could be, I guess, a number of reasons why a header could crack.

Most of the time, the crack goes around a pipe. I would think that could be caused by several things... bad motor mounts so the engine is excessively shaking, a bad or missing transmission exhaust bracket, the abscence of which is allowing the exhaust system to shake too much, or even a header that just rusted in one place or another.

I have my original header though. Our header's come from 6 exhaust ports to two at the cat. The cat has been changed a few times (4 to be exact... 2 factory cats, and two aftermarket things that didn't last long). The rear muffler has been changed about 5 times over the life of the car...
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Cosmo - 1985 BMW 325e, Single Owner, 265,000+ ORIGINAL miles and still going strong! But now on the East Coast and the salt air corrosion is eating my beautiful car alive... Sad

mik_meister_99 · Joined: 24 Mar 2004 Posts: 121 Location: North TX

If you have an oil leak, the 'pipe' your wrench is referring to could be the one from the intake orings on the header. A crack in the header would be much different than a crack in the 'pipe'. This is part #11 on this diagram . Just had mine replaced.
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1988 325is 5-speed (Molly)
172k
You know you've got an e30 when you turn your radio up to mask valve clatter.

gr8acclaim · Joined: 17 Mar 2005 Posts: 95 Location: Greenfield, Indiana

I don't know for sure on these cars, but I owned a GM car with a little 'shorty' type header on a 2.5L 4-cylinder. It developed a crack in a WELD where the two pipes joined on the header. That was not long after I bought it -- or it became obvious not long after I bought it at least. Those were prone to cracking there though, so I don't know that is of any help here or not.

I ultimately went through two more used junk-yard parts that broke that same weld before I found an earlier car with a cast iron exhaust manifold and replaced it with that to cure the problem. I was told by some junk-yard guy at one point that the problem on those was partly due to the fact that they were so short, and so they got a lot of heat distortion and stress on that weld, being so close to the actual head and exhaust port. On these cars however, that joint is WAY farther downstream. So my post is probably not relevant at all...
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1992 Plymouth Sundance Duster -- 263,000 miles -- RIP due to rust;
1991 BMW 325i -- 158,546 miles (plus ? miles when the odo didn't work!)

idanity · Joined: 21 May 2005 Posts: 3097 Location: N.W.U.S.A.

my 1st car (79 toyota corona) had a crack in its exhaust manifold. so big it looked like a taco, and i could drop coins in it.
it was loud but i only had bicycle tools, and when i tried to fix it, i made more problems than it was worth, plus lost a day or 2.

i never saw one in the bmw exhaust, but i know its fairly common on older cars.
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m78 · Posted: Wed Feb 08, 2012 10:42 am Post subject:

beejay · Joined: 18 Nov 2002 Posts: 1158 Location: Eastern, Pa

You need to have your shop clarify what is cracked or leaking.
You have the:
1-cast iron exhaust manifold
2-the headpipe/cat converter assy.
3-rear pipe/muffler assy.
there's only 3 sections to the 325i exhaust.
Look at a diagram on real oem and it will help to visualize it.

So find out where the leak is, that will determine what to do next. the exhaust is really not that hard to work on on these cars. Of course a torch may help for old rusted nuts.

A crack in the pipe/cat assy can be welded. I had a hole in my cat welded and it's still holding up after many years.
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Bob
92 325ic gone Sad

14 BRZ ltd
05 Tundra SR5 TRD
01 VFR800fi - 03 DR650S - 83 CB1100F - 82 CB900F - 69 CB750

idanity · Joined: 21 May 2005 Posts: 3097 Location: N.W.U.S.A.

m78 isn't referring to the exhuast..
rather the oil return pipe..

and its a bit of a pita. i think you may have to remove the intake manifold/plenum.
the pipe should be able to retract into the block via a spring, and snap back up.
however, if you only have a crack in that pipe,
that pipe should be able to turn in place, and perhaps you can use jb-weld over the crack.
its just an oil return...and i don't know how it would ever get cracked in the 1st place.

this is of course, referring to #11 in the diagram.
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