Date: Tue, 09 Apr 2002 14:12:51 GMT From: Bob <uctraingLOWSPAMnopsamanet.com> Subject: Re: Oil in cooling water
On Mon, 08 Apr 2002 22:50:40 GMT, R&L Mieras <rlmierasnopsamsplanet.net> wrote: >Actually Bob, headgaskets DO wear, because of different expansion rates of the >aluminum head and the castiron block, actually, slowly over time, grates the >headgasket down. Just my 2cents worth, also just had to change my headgasket :( A good point. I always think of them as "breaking down" rather than "wearing out" but I suppose your theory might hold water (no pun). I've always assumed that it was temperature, pressure, but mostly loss of resiliency over time that did them in. I don't suppose we could get Saab to give us the engineering analysis that they did on the NG900 and determine exactly why they changed the torque specs (lower torque). I assumed that less pressure left more thickness in the gasket and resulted in longer life under my theory, but I could fit your theory about movement/expansion and less torque allowing for more movement between the two also. Bob