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Over pressured cooling system.

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whodatgabe

New member
I have a newly rebuilt 302 with a Volvo Penta out drive. I added a heat exchanger. At high RPMs cooling system is becoming pressurized and pumping the water out. I just remove the heads had them checked and replaced the gaskets. It seemed to help some. trying to figure out what else could cause this problem.could a bad gasket in the exhaust riser call the system to be pressurized?
 
a closed system should build pressure as it heats up....but shouldn't exceed ~ 7 psi or so....is the heat exchanger large enough?
 
makomark said:
a closed system should build pressure as it heats up....but shouldn't exceed ~ 7 psi or so....is the heat exchanger large enough?
Click to expand...

Idk. I took it off a 351. Its not overheating. Until it blows enough water out off course. Before I did the repair it blew the water out since I replace the head and gasket i took the thermostat out and it blew the water out of the overflow at 120 degrees. I was able to run it a lot further than before I replace the head and gasket.
 
You mention "water" and "blowing water out"!
Are you using water or Ethylene Glycol in the closed cooling system????
This must be Ethylene Glycol.... not water!

As for the exhaust manifold question...... is this a "half closed cooling" system, or a "full closed cooling" system?
If half system, the exhaust manifolds would have no bearing upon this problem.

Pick up some Hydrocarbon test strips, and see if your coolant shows any signs of hydrocarbon contamination.


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You talk about a repair involving a head and gasket as well as the addition of a heat exchanger. I like to deal with problems one issue at a time.

What was the issue with the engine that caused you to do a head/gasket repair?

"Installing" a heat exchanger on an engine that did not have one before can get "sticky"
There are a number of possible configurations. Primary concern... is this a "full" (manifolds included on "fresh water side, elbows on raw) or "partial" ( manifolds and elbows on raw water circuit) system ??
 
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