My 940T exhaust manifold gaskets are lasting only about a year before blowing out in various places. I use OEM Volvo Set (p/n 271704) and maintain the proper torque.
I have 2 questions:
1) Is if there is a better brand gasket to use?
2) Should I consider having the manifold machined by a shop to ensure the contact face to the cylinder head is true?
Beyond using OEM studs, nuts and gaskets per the FAQ Section, and maintaining proper torque, I don't know how to make these gaskets last any longer than about a year.
BTW, there are no obstructions in the exhaust system or catalytic converter. These have all been replaced within the last year and do not cause any back-pressure issues.
Thanks everyone!