Manifold Vaccum

[webng]

Is a reading of -20 hg when the car is at idle alright? It's a RB25DET Neo S2 Stagea.

[The Dan]

That is fine. Any lower than 20 and I would be checking timing and/or vacuum leak though. good trick to check for leaks is to buy a can of Aerostart (I prefer 'Start'ya'bastard for reasons we won't get into) and while the engine is running, spray it over the vac hose connections and where the cooler piping runs. IF there is a leak the idle will change fairly dramatically.

[webng]

That is fine. Any lower than 20 and I would be checking timing and/or vacuum leak though. good trick to check for leaks is to buy a can of Aerostart (I prefer 'Start'ya'bastard for reasons we won't get into) and while the engine is running, spray it over the vac hose connections and where the cooler piping runs. IF there is a leak the idle will change fairly dramatically.

Cool, when i boost up and release the throttle it drops to about -25hg.

Apparently i have a leaky head gasket, should these readings be in any way connected?

[The Dan]

Cool, when i boost up and release the throttle it drops to about -25hg.

Apparently i have a leaky head gasket, should these readings be in any way connected?

Who told you that you had a leaking head gasket? And what tests were performed to diagnose it as such?

[webng]

Who told you that you had a leaking head gasket? And what tests were performed to diagnose it as such?

Awhile ago i had a mysterious disappearing coolant from the overflow bottle issue which a radiator specialist fixed by replacing the top tank. He also diagnosed a warp head gasket. I then took it for a 2nd opinion at a reputable mechanic who do a lot of work with RB's and he did a pressure test and he also diagnosed the same, albeit he's going to charge me a lot less then the radiator joint. Still... $1600ish is bye-bye to exhaust system for awhile though.