Sounds kike a bad head gasket or cracked head. While the engine is revving, the combustion gasses are getting into the cooling system. You do not see the "bubbles" while the engine in being revved due to water pump pulling through the coolant tank. When the engine returns to idle, the pump pulls less allowing the air the enter the tank quickly, releasing the bubbles. This is why both the cooling systems on both the diesels and water boxers have problems after extended highway runs. The gasses keep building up until there is no place to go and they either vapor lock the pump or blow everything out the relief valve. Dennis
-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of stephen de la salle Sent: Saturday, August 17, 2002 6:51 PM To: vanagon@GERRY.VANAGON.COM Subject: bubbles in the coolant overflow tank on 82 diesel westy Rebuilt engine approx 4K miles ago - for the last 2K miles I get a fair bit of dampness and dried salt around the top of the overflow bottle - tunrs out hat if I rev the engine, & hold it - no problems. If I then let the revs drop back to idle - I get a 'burb' of gas coming via the metal expansion tank cap to the oerflow tank. It's a puzzle, if it was a leaking head gasket I'd expect bubbles as I rev the engine - but I only get them when the engoine returs to idle.... any thoughts out there....
steve |
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