Al Gietzen wrote:

Just kicking this around - What exactly to we want our coolant pressure
sender to tell us?

I have a system with a fill tube connected on the inlet side of the pump
where I'm putting a 24# cap.  The over flow goes from there to a 1 1/2
qt bottle with a 15# cap, which also has a level sensor that tells me
when the bottle is empty.  Any overflow from that cap goes overboard.
The idea here is to always have positive pressure on the inlet side of
the pump.

I was going to put the pressure sender on the outlet side of the pump,
which gives me a pretty good idea of the pressure in the block (but what
good is that?), and if that pressure went to zero it would tell me I had
a catastrophic loss of coolant.

A racing friend thought maybe better to know the pump inlet pressure,
thinking if that went to zero I could know I lost coolant, or a pressure
cap (or both) failed, or it would just tell me if I should worry about
pump cavitation.

Or maybe the place you want to know the pressure is in the block, like
at the heater hose outlet.

Or maybe it doesn't matter; if all it's going to tell you is whether you
had loss of coolant.  And there will likely be other things that will
tell that rather quickly as well.  Maybe we don't need a pressure
sender.

Comments?

Al Gietzen

I would like to see three pressure measurements. Out of the pump. Out of

the

block and in to the pump. It is handy to pre flight the systems for leaks
when the engine is cold by pumping up the system to about 30 psi and

watching

the pressure gauges. This works for external as well as internal leaks.

Paul Lamar

Peter Cowan/Lexy Cameron wrote:

Hello Paul.
Your point is good about checking for leaks but one sender anywhere will do
that. What are your reasons  and uses for two other senders?
Peter

Well we would like to correlate the pressure drops with our water pump testing
to determine the degree of restriction in the block and radiators. Vance is building a
3 HP water pump dyno and along with my test and his test we should be able to get
some sort of overall mathematical handle on the cooling system. There are
so many variables that it is hard to sort it all out. Ed Anderson is working
on measuring the temp of the cooling fluid as it goes into and out of the engine 
and/or as it comes out of the radiators.

Paul Lamar
 
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