Date: Wed, 24 Jan 2001 16:58:53 -0600
Reply-To: Steve Gough <vw@EMRIVER.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Steve Gough <vw@EMRIVER.COM>
Subject: Coolant air, overflow, fried head gasket, "burping" out air (long)
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Great list. Your advice (and patience with my first post) please:
I'm now the proud owner of an '86 Westy, bought from a guy who'll remain anonymous. He lives 950 miles away and I drove that newly purchased van all the way back to my home in St. Louis fighting coolant overflows and the blinking red light.
Before I bought it, PO did flush and fill, then later a radiator replacement. He worried that not all the air was out yet and advised I stop and "burp" the expansion tank if the blinking light showed low coolant.
The engine ran (still runs) great, plenty of power. But after only a few miles, she spit a lot of coolant out of the fill (license plate) tank. (I trailed a nice steam cloud as it hit the muffler). Following PO's advice, I would "burp" the expansion (with pressure cap) tank. Lots of "air" would come out. This went on for many, many miles: coolant overflow and/or blinking red light, find a place to stop, "burp" tank, sometimes add coolant. The intermittently overflowing fill tank would leave a nice mist of coolant on the back window at interstate speeds.
Maybe you are laughing now. At about mile 600, I realized that "burping" the expansion tank of a hot engine was just flashing a lot of the coolant to steam (as it went from 14psi or whatever to zero) and the "bad air" I was letting out was steam and that I was probably forming steam voids elsewhere in the system as well. Very stupid of me. If anything, stopping every 15 miles to make the problem worse. Perhaps I define "knowing enough to be dangerous."
Engine runs great still, but now I get intermittent white smoke from the tailpipe and water dripping from it. Even after I stoped my dumb "hot burping," still got a lot of air coming out of the expansion tank (replaced the pressure cap about halfway through the trip, hoping that was the problem). Evidenced by a train of little bubbles entering the fill tank when the engine was hot.
I am fearing that my hot-engine-burping, or maybe the flush and fill or radiator replacement led to overheating and a bad head gasket. I believe the PO's statement that the recently redone heads were fine before. I checked the temp gage every 10 seconds, I swear, and it never got over 3/4 scale (stopping, slowing) and usually (on the highway) sat right over the little light.
Something I learned that may help you: The low coolant light is a "latch" circuit: It stays on until the ignition is cycled off no matter what--I could often just pull over, turn off the ignition, restart, and no blinking light. I attributed these transients to steam slowly venting out of the expansion tank (that little valve is very small).
Please advise: Have I fried a head gasket? How can I tell if combustion gases are getting into the coolant and forcing it out? I checked the archives: Nobody has warned of "hot burping." Is it so obvious (or am I that dumb)? Can these engines really run so well when blowing/sucking coolant into/out of the cylinders?!
BTW, I'm not looking to blame the PO or anybody but myself. Just looking for advice on cause/diagnosis, and perhaps to warn others. Feel free to highlight, make fun of, or discuss in detail my ignorance.
Thanks,
Steve Gough
'86 Westy
gone but not forgotten: '69, '72 Beetles
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