In a message dated 8/23/01 11:57:31 AM, VW85Westy writes: << In a message dated 8/23/01 11:41:46 AM, JKrevnov@AOL.COM writes: << But, first, are you sure the valve plate was sealed to the body of the pressure cap? >> What do you mean by this? >> Peter, The check valves of the pressure cap are part of a disk which is inserted into the pressure cap. This valve plate, for want of a better name, has a sealing ring on its circumference. Tightening the cap to the spigot of the pressure tank seals the valve plate between the pressure tank and the expansion tank. If the valve plate is not forced against the body of the cap when it is tested, it will not hold pressure nor vacuum. In my experience, the pressure cap can fail whenever a foreign particle (aka, caa-caa) becomes lodged on the sealing surface of one of the check valves. More than once, I have dismantled (carefully!) the innards of the old style black pressure caps in order to clean the check valves. Once I found a thread of paper in there from the cap liner on my well-used coolant refill jug. Another time I found a Blue Spruce needle. Bet you can guess what kind of trees overhang my drive. In light of this, and since you had a recent rebuild, perhaps the jobber was not diligent in cleaning the engine before assembly and there is some swarf circulating through your cooling system. A VERY minor piece of leftover machine work hung up in either pressure cap check valve is all that it would take to prevent your cooling system from reaching the correct operating pressure. Rich |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.