Re: Another Commute

[Tom Harais <tjhemh@domain.elided>]

Tom:

The type of radiator cap does matter for a "closed system" as you
propose. Fortunately, almost all modern systems are "closed" and hence
if their radiator cap will fit, it will work.

What is important: Virtually all radiator caps allow coolant to escape
out the overflow tube when heat expands it. But older ones, allowed air
to enter to replace lost fluid through the center of the cap, when the
coolant cooled down. They had to do this to avoid vacuum and having the
raidator crushed by air pressure.

Now, with the closed systems, they allow the coolant from the recovery
tank to flow back in and replace that which flowed out from heat
expansion. This means they allow the flow in from the same overflow
spout that it went out on.

If you use a non-closed system type, the coolant in the overflow tank
won't come back in. The cap will let air in.

Fortunately, most overflow kits come with an appropriate radiator cap.

Tom H.