Replacing exhaust manifold gasket

I need to replace the Exhaust Manifold Gasket on my '88 highline as it is blowing but I've been turned down buy two mechanics!

Apparently the head studs can snap off and replacement means removing the head to drill them out.

Does anyone have experience on how likely this is to occur? I'm getting worried about an apparently simple job.

thanks

Mark McLennan my mechanic just replaced my manifold for a super curly stainless jobby without snapping any of the headbolts. Yes there is a danger and it does happen, but it can be done. Obviously if a stud snaps the price of the job will go up, but there is no way around that if it happens.

James 

On the earlier E28 manifold one big problem is getting a wrench on the nuts at all. You need a thin-walled slim ended ring spanner, nothing else will do. If the nuts are badly corroded they are in danger of rounding off if you use a bi-hex, so use a wall drive wrench if you can get one.

About half the nuts can be accessed with a socket OK from beneath; these are the easy ones... The one at the back of the head is a complete sod; I went out and bought a stubby ratchet spanner set right after wrestling with that little so and so....

The later highline manifold is completely different though, a bit easier in some ways I reckon. 

I would recommend dousing the nuts with oil when the manifold is still warm. This should be done several times if possible- but not when it is so hot the oil will burn right away; that would be stupid....

If there is oil on the nuts when you are trying to loosen them this will only cause trouble if the wrench is a bad fit on the nut for some reason; the amount of torque required to shear off a stud is actually quite small. If you are worried by the oil, remove it with tar spot remover or similar.

If the worst happens, a gentle tap on the remains of the stud will often loosen it enough to turn it. Then there are easy-outs and the like. Very often the stud will be easy to turn once the manifold is off anyway.

If just a tiny bit sticks out it can be built up with MIG weld metal and often the heat from welding also loosens it; -bonus....

I think there IS access for a small right-angle drill should it be required, (even on 87-on cars where the brake master cylinder is in the way)  but it will be very difficult to see what you are doing. I have fitted a drill chuck to an angle grinder for this exact purpose (a top bodge, no...?) , but I've never had to use it on my BMW....

Finally on my cylinder head (they all came undone OK!!! ) I noticed that all the holes were deeper than they needed to be- this means you have every chance of drilling and then freshly tapping to the bottom of the existing hole, then fitting a longer stud.

cheers

Sohlman wrote: I don't think i can really add to this as i was off playing golf whilst my mechanic was doing the job.

Oh, how the other half live....

usually if there is anything sticking out you can extract it, especially if you are prepared to go down the MIG route if required.

Your friend's advice is fairly sound IMHO except that some studs will have nuts that unscrew OK but will be tight in the head. The other little problemette is that access for cutting many of the nuts off is almost completely non-existent....

cheers