Head bolts loose

[beoutside]

At 50000 miles after a head rebuild I had 4 bolts lossen enough to cause a head gasket leak , was running great, make sure your block has very clean or chased threads as in traceyssoaps tutorial but I would change the oil lube to red permatex. That is a tip from a 40 year veteran mechanic. It acts as a lube and will prevent bolts from coming loose but not work like thread tight. I had followed all the instructions and double checked my torque settings. We have a volvo XC 1999 V70 and I had the head redone professionally at a machine shop at 170000 due to a sticky hydraulic valve causing a burnt/blown hole in a Exhaust valve.
The symptoms were intermittent coolant loss and finally stumble starts then fine as it warmed up. Looking at the head gasket there are no compromises to see but we're it should be clean around the cylinders it has carbon deposits corresponding to the " loose" bolts. Hope this helps other Maintence OCD types like us who expect 400000 from their volvo.

[Clemens]

Thanks for that info. Nothing i would have expected. Life is full if surprises, ain't it?

[rspi]

I have done several heads with oil on the bolts, some with over 40,000 miles with no issues yet.

Have you pulled the head and verified that bolts are loose? These heads have some issues with cracks between the valve guides.