Hi Folks,

the right (passenger side on LHD) exhaust manifold on my 1998 XKR is broken and needs to be replaced. The bolts look like they haven't been touched since the car left the factory.
I had a look at it and removed the air intake, should be doable.
Just to try, I loosened two bolts a little bit.
They moved, but were really hard to turn once cracked open.

What would you recommend to get them out unharmed:
Removal with engine hot?
Any other hints?

I think I'm goona be in big trouble if one of these buggers breaks during removal!
Of course I will not reuse the bolts or gaskets with the new manifold.

Thanks for your ideas

Stefan

 

I've had to remove rusted bolts from exhaust manifolds (I assume these are bolts, not nuts) and they're never fun. PB Blaster works fairly well if you soak the nut or bolt several times. What works even better is to use a propane torch to heat the nut first, or the area surrounding the bolt, then soaking it down with PB Blaster. It can be time-consuming, but it sure beats trying to remove a bolt or stud that's sheared off.

I'm sure some other members of the forum have experience specific to the removal of the exhaust manifold. Good luck!

 

max224,

these are bolts, so it will be difficult to get some lubrication in there.
I guess 8mm, which is not really strong as well.

But perhaps I'll drive the engine hot and try then! Not good for my hands thou.

Stefan

 

You might also try tapping them from the side (not too hard) to try break the rust bond. Unfortunately, at the end of the day, there's no guarantee what will work and what won't. Sometimes it takes repeated tries with heat, penetrating oil, prayer and more than a little patience, but however long you think it takes, trying to remove a broken bolt will undoubtedly take a lot longer.

 

max224,
thanks for your suggestions, much appreciated.

I searched the TSBs, and found #303-03 - Exhaust Bolts.
It seems that on early XK8 VIN 1001 - 6675 the manufacturer used low grade bolts for the manifolds. It is stated that these are likely to sheer upon removal attempts. The proper method to remove the exhaust manifolds is to remove the engine first(!), drill out the bolt's heads, take off the manifold and apply heat to remove the remains of the bolts.

Thank god my car does not nearly fall into that VIN range!

Interesting bit of information within this TSB is the fact that they seem to have used thread locker on these bolts. This explains why the two bolts which I tried to remove are so hard to turn. Tried again yesterday with engine hot, seems better. So I'll go this route.

Best
Stefan

 

If a threaded fastener is hard to remove always use lubricant and alternately loosen and tighten. This helps to clean the thread as you go.

No problem with bolts and penetrant because the penetrant will wick along the thread.

Even with the biggest fasteners ... finesse before force.

 

plums,

you're right, that's the way it should work out.