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rvtips · 10-27-2022, 10:42 PM

On a 2003 Safari with the 350 ISC Cummins ,How does the coolant flow.
From the surge tank.In at the bottom or out at the bottom?and what about the two smaller hoses at the top?

jacwjames · 10-28-2022, 07:18 AM

One of the small hoses comes from a fitting near the metal tube where the thermostat is on the engine, it carries quite a bit of coolant while the engine is running.

The larger hose at the bottom the coolant goes to the radiator.

I thing the other small hose goes to the radiator. I thing this is more of an air purge.

avfordguy · 10-28-2022, 09:43 AM

Quote:

Originally Posted by jacwjames

One of the small hoses comes from a fitting near the metal tube where the thermostat is on the engine, it carries quite a bit of coolant while the engine is running.

The larger hose at the bottom the coolant goes to the radiator.

I thing the other small hose goes to the radiator. I thing this is more of an air purge.

Industry commonly refers to that coolant "tank" is actually a "degas" bottle. It removes all the air in the coolant system.

alank · 10-28-2022, 05:53 PM

My opinion would be that there is very little coolant flow in the tank. It acts more as an expansion tank providing a place for the expansion of hot coolant to go, and at the same time providing a place for air bubbles in the system to eventually work their way, through any of the hoses, to the top of the tank.

Argosy · 10-29-2022, 10:11 AM

As the coolant heats up it expands into the surge tank, when it cools it’s drawn back into the radiator. The second tube is an overflow. If the expansion tank is over filled the excess antifreeze drains onto the ground rather than blowing the tank/bottle open.

jacwjames · 10-30-2022, 08:21 AM

The tank that I replaced on my 2002 Monaco is more then just an expansion tank. The small hose that comes from the top of the engine does carry quite a bit of coolant, my guess is several gallons per minute. The bottom larger hose going to the radiator allows for this coolant to flow.

The second smaller hose is to allow air to be purged from the radiator.

There is a standard radiator cap on the neck of the small tank with a bleed hose, I don't think I've seen any coolant purge from the small hose.

So it's important to know what type of tank you have, is it a expansion tank or a type of surge tank.