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Subject:Cooling System Results - Interpretations anyone?
From:Richard Golen
Date:Mon, 7 Jan 2008 13:20:44 -0500

Hi,

Admittedly, I got my degree in A/C Volkswagens, so from time to time
(despite owning a Vanagon and Eurovan for 15 years) I am still
stymied by various Vanagon maladies. Last weekend the coolant system
in my 87 Westy was acting up, spitting up coolant on a 900 mile round
trip last weekend. For all intents and purposes it looked like a head
gasket/cracked head problem. The 87 has 150K miles, so its probably
due for a new engine, but I'd like to delay that inevitability until
spring, and use the Westy around town (dump runs, grocery and beer runs, etc.)

This morning I did a pressure test on the cooling system. Here are the results:

1. Coolant tank cap - appears not to be functioning. I can both blow
into the cap and suck through the cap. There doesn't seem to be any
pressure resistance in the cap. I'm assuming that this is not normal?
The cap should only let fluid go into the overflow tank under
pressure? If the cap is bad, then would this be the reason why the
overflow tank was puking out coolant and spraying coolant?

2. I used Bob Donald's cooling system testing protocol. With the
engine off and cold, I pressurized the cooling system to 11 lbs. The
pressure dropped down to 10 lbs after 10 minutes.

3. With the engine running, the system pressure started out about 5
lbs, and once warm, ran at 12 lbs at 2200 rpm. When dropped back to
idle the pressure briefly rose to 13 lbs, then down to 11 lbs.

I am assuming that #2 and #3 are in the normal range? Perhaps the
pressure cap was the problem all along??

Of course, just to remind me that Vanagons demand attention, while
testing the system, the idle seemed to hang at 2000 rpm, but I'll put
that in a separate email.

Thanks in advance.

Ric