Author Topic: manifold cracked (Read 2762 times)

IStourerD · « **on:** August 05, 2010, 02:11:08 PM »

hi!
just wondering if many m42 owners have had their exhaust header crack between the flanges and the pipe. mine seems to have cracks on 3 of the pipes.
im getting an exhaust made up for the car next week and thought that whilst its apart i was going to weld it all up again. but this involves unbolting the header off the head. im just a bit worried that bolts might start snapping off due to corrosion ect, or are these normally ok as long as i use plenty of penetrating oil?

monko141 · « **Reply #1 on:** August 05, 2010, 09:51:07 PM »

I would say you have a rare problem. I would venture to say you are missing the exhaust hanger that bolts to the transmission.
What will probably happen when you try to remove the header is, half nuts will come off and the other half the studs will come with them.

IStourerD · « **Reply #2 on:** August 06, 2010, 07:33:13 AM »

yeah you are right about the transmission hanger. when i bought the car i noticed that there was a remenence of something to do with the exhaust. the problem with living in england is they use so much salt on the roads in winter time that steel exhaust components rust really badly. i am a porsche technician and the exhausts on them suffer massively because of this.
good news about the bolts and studs!
thanks for the reply fella!

nicknikolovski · « **Reply #3 on:** August 07, 2010, 06:03:27 AM »

Just a question about the cracked manifold. Can you here a faint ticking noise from inside your car on the right hand side? I removed mine previously - not too bad, except the bloodly steering column extension is in the way. I had some nuts come off and some with the studs like monko141 said. The worst part was actually trying to unbolt the 4x nuts between the manifold and the catalytic converter. They were solid until I sprayed them with penetrating oil and left for about 15-20mins. Just be careful with these as others have snapped them.

IStourerD · « **Reply #4 on:** August 07, 2010, 12:17:02 PM »

yeah thats right! i can hear it more on start up on a cold morning, really annoying ticking noise. i can alos feel it if i get my hand around the individual pipes.
luckily i have already had the 4 bolts between the cat and manifold off when i did my clutch about 6 months ago. i put them back with plenty of copper slip so im hoping that they will just unbolt nice and easily. im thinking i might wrap the pipes once its all welded up aswell. might help a little?

nicknikolovski · « **Reply #5 on:** August 08, 2010, 12:06:02 AM »

Yeah I guess so, or you can just get that high temp paint stuff as well. Or get a shop to get them ceramic coated. Up to you mate.