Ok folks, not sure about this one. I bought my 97 Deville with 75k on it. At 95k it started the dreaded coolant loss from the head bolt pulling at the #1 hole. Everything was dropped out the bottom, the motor received all new seals and Northstar Performance studs and new head gaskets. In the last 4 years I’ve run this up to 260k miles and it’s been a champ. Recently, if I hit the gas hard from a stop there would be a little detonation and white smoke out the tailpipe. It stops as soon as you back off the throttle. The car does not overheat, there is no overpressurization in the overflow tank, but over the course of 3000 miles I have to replace a little coolant ( about a quart). I never use any cooling system sealer, but decided yesterday to throw the bars tabs in the radiator. I’ve never seen any sealer do anything on these car’s head gaskets but for $5 I figured there was nothing to lose, and with the NP studs I have some doubts as to whether it actually is the head gasket. It seems to seal whatever was causing the smoke which really surprised me. 250 miles on the quick fix and it seems fine.
Am I missing something that could allow coolant into the combustion chamber besides the head gasket? I suppose there could be a crack in the head, but I would think that problem would show to be more of a smoke show no matter what throttle is used. I have not done a cooling system pressure test yet, I’m looking at all the possibilities first. Any ideas?