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Patrick

Hello All!
I`m just trying to understand something about the Coolant Reservoir of the 924. Can i safely assume that it functions as an extension of the top header tank (since it also has a pressurized cap and overflow tube)?

If it does, then shouldnt the overflow tube be connected to a coolant recovery tank so no coolant is wasted? Or is the expansion tank of a nature that you loose minimum amounts of coolant out the overflow tube as compared to the radiator setup without an expansion tank or even a coolant recovery tank (so coolant just drips out to the ground)?

I sure would prefer to minimize coolant loss (at least till my next coolant change) given our extremely hot tropical temp.. Anyone care to enlighten me on this? Thank You!
patrick
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1979 924 U.S. version
Single sidedraft Weber 40

!tom · Posted: Sun May 19, 2013 1:37 am Post subject:

The expansion tank is just that; a tank that allows for the expansion of the coolant. There is a maximum fill line so that there is room for air in the tank.

A properly working system won't let coolant go out the overflow tube as the coolant level shouldn't get that high.

The system works differently than the type that uses the external tank. An external tank system is filled so that the coolant level goes up to the cap, whereas the expansion tank system allows for some air between the coolant and the cap.
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78 924 NA
5-lug

Patrick · Posted: Mon May 20, 2013 12:06 am Post subject:

Thanks for the response tom! I understand the part about having a good amount of airspace between the coolant and the overflow tube, thus not allowing any coolant to go out the overflow hose.

But i was thinking more of times when the engine would be running hot enough to open the expansion tank cap`s safety valve and thus allow coolant to exit the overflow tube? Or does this happen only when the engine is close to or is already overheating? thanks again!
_________________
1979 924 U.S. version
Single sidedraft Weber 40

!tom · Posted: Mon May 20, 2013 1:29 am Post subject:

Coolant should only go out the overflow tube if you have over filled the coolant, or some other sort of failure.
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78 924 NA
5-lug

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Patrick · Posted: Mon May 20, 2013 11:13 pm Post subject:

Ok my questions are answered, thank you both!
_________________
1979 924 U.S. version
Single sidedraft Weber 40