Skip to main content
Gerry | Vanagon
Checking account...
← vanagon.com home · Continue the discussion in the forum
Subject:Anyone know thread size of coolant bleeder bolt on radiator?
From:TinkerMan
Date:Thu, 15 Aug 2002 22:33:14 -0700

As per Darrell Boehler's suggestion for a coolant
pressure sender location, I'm considering installing
it in the coolant bleeder bolt hole on radiator.
Before I start removing that bolt just for thread
measurements and get air sucked in, anyone already got
the thread specs?
Also, IMO, a pressure switch might be preferable to a
gauge since it can activate a buzzer long before I'll
notice the gauge.
In fact, I was thinking about devising a "dynamic
coolant pressure monitoring" system, similar the
already present OEM system ("L" board, inside the
speedometer) used to monitor the oil pressure system.
I would activate the pressure warning based on coolant
temperature, i.e.:

1. Minimal pressure existence above a coolant temp
threshold (e.g. 5 psi above 90 degrees Celsius).
2. Always test for excessive pressure (i.e. over
15psi), warning of a failed coolant expansion tank
cap, BEFORE any hose bursts...

Questions:

1. Anybody got measurements/graphs of cooling system
pressure as function of coolant temperature?

2. Anyone know of cheap 15-20 psi pressure switches,
possibly available from car parts shops (not
necessarily VW part, as long as it's OK quality).

3. I'm also looking for a 80psi pressure switch, to
warn of a failed oil pressure release valve...

4. If anyone has a another good suggestion about
easily tapping a pressure sender/switch into the
coolant system (e.g. to the coolant expansion tank or
vicinity), without drilling or such, I'd be glad to
hear (better yet, seeing is better. Any pictures?...)

=====
Cheers, T-man.

__________________________________________________
Do You Yahoo!?
HotJobs - Search Thousands of New Jobs
http://www.hotjobs.com