At 200K, especially if the engine has been turboed, one might expect that some things, including the head gasket, have suffered some wear. Have you checked the radiator or the coolant expansion tank for air bubbles and/or oily film, which would indicate that exhaust is blowing by the gasket somewhere and entering the coolant system?
Another possibility, if the smoke is not too heavy or not affected by pressing the accelerator, would be oil leakage from behind the head or at the CAS o-ring, running down the back or side of the engine and getting onto the exhaust pipes. That oil would burn and smoke for a while until gone, then disappear. However, at 200K, overnight leakage at the valve seals into the combustion chamber could also be the reason you're getting smoke upon start-up that disappears after warm-up (running burns up the leakage, and the smoke disappears). This could be the symptom that starts you thinking about a rebuild or a replacement engine, and is my best guess without any sort of visual inspection... Good luck with it, the leak down test should prove valuable. Jerry aka LGO -----Original Message----- From: Chad J. Douglas <[email protected]> To: [email protected] <[email protected]> Cc: Ken Riley <[email protected]> Sent: Sun, Apr 10, 2011 11:23 am Subject: Head Gasket? 1997 STO - - 200k k miles Sometimes when you start it up from cold, it smokes like a freight train for 20 minutes (although, I can’t remember the last time I saw freight train that “smoked like a freight train.”) Sometimes, just a few minutes. Sometimes a puff. Sometimes nothing at all. Once the engine is warmed up, no smoke at all. I tested it in high vacuum to check for valve seals, and even under high vacuum (revved 1st gear to redline, took foot off gas for 2-3 seconds, then back on) I get NO smoke. Engine runs GREAT. No strange behaviors except for the smoke. Even when it’s smoking - runs very well…. Engine has no appreciable blow-by – you can take the oil cap off when the engine is cold and there’s just the normal amount of crankcase pressure there. So, I’ve come to this idea: there is a small crack in the head gasket between one or more cylinders and the pressurized oil passageway. While the engine is cold, oil can leak through, but then it seals up when warm. Not sure what would explain the varying “smoke times.” Any ideas on what to check next? I recently purchased a leakdown tester from Harbor Fright (pun intended), but I’ve never used one. It seems that leakdown is a good next step…so….anyone want to tell me how to use one of these things? = _______________________________________________ iatapower mailing list [email protected] ttp://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
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