Yeah trog, yer points are sound. After I posted, even I thought what I wrote wasn't the complete picture regarding gasket failure. I was just following up on Skip's description of a mechanic seeing oil in the tank. I have to question your statement that there will be no pressure in the coolant reservoir tank when cold. I think it really depends on the condition of the relief valve within the reservoir cap. Those small (just a rubber washer under spring pressure) things are highly suspect to degrading, fouling, and glogging with crystalized coolant gunk and degrading hose material. It can either fail in an open position, or locked shut to the point where it fails to open at all, which would then lead to over-pressure and leaks along hose connection points, the water pump and so forth. With a properly working reliefe valve, there will be residual pressure, even when cold. Cold being relative. Perhaps the amount of coolant vs water also effects the residual pressure. More water in cooling systems such as mine that don't see freezing temps may have more residual tank pressure.

What you may have uncovered is the dirty little secret that with the stock SAAB headgasket plus an engine (turbo especially) beyond so many miles, there is no way to absolutely prevent cylinder gases from escaping into the coolant channels via the head gasket. A certain amount of leakage is therefore acceptable up to the point where the symptoms become evident and the performance is effected. The same logic applies to any fluid leak. It leaks until it becomes grossly evident and you replace the failed seal or component.

The ideal head gasket repair involves entire head replacement (those poor things warp all to heck over time) along with milling the engine block surface flat and use of a performance gasket such as copper of the proper thickness.

posted by 198.81.26...

• Thanks to the board for valuable info, Skip, Mon, 6 Jan 2003 10:11:04
  • More info, everyone's right :), Skip, Tue, 7 Jan 2003 09:17:02
  • Re: gasket, MS, Mon, 6 Jan 2003 15:40:15
  • Re: tank pressure, MS, Mon, 6 Jan 2003 15:37:20
    • Re: oil, constant coolant pressure, gasket failure, MS, Mon, 6 Jan 2003 20:16:10 <-- Viewing This Message
      • Re: u make a good point.., trog100, Tue, 7 Jan 2003 07:38:01
    • Re:nope there should not be any pressure when cold.., trog100, Mon, 6 Jan 2003 16:16:25
      • I agree, Bill U, Mon, 6 Jan 2003 22:38:52
      • Re: Re:nope there should not be any pressure when cold.., JohnK, Mon, 6 Jan 2003 16:35:28
        • Re:yes a sniffer will show it up.., trog100, Mon, 6 Jan 2003 17:11:17
          • Re: Re:yes a sniffer will show it up..& spotless plug, JohnK, Tue, 7 Jan 2003 12:29:00
    • Re:nope there should not be any pressure when cold.., trog100, Mon, 6 Jan 2003 16:16:08
      • Re:one other thing.., trog100, Mon, 6 Jan 2003 16:54:55
        • thanks, trog, Russell Giuliano, Mon, 6 Jan 2003 20:17:18
          • Re: the import thing here russel.., trog100, Tue, 7 Jan 2003 07:52:02

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