LS3 coolant pressure issues
Thread Starter
Launching!
Joined: Jun 2011
Posts: 244
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From: Walnut Creek, ca
LS3 coolant pressure issues Hey guys,
I have a LS3 that I have in a 64 Impala. I have been building it for some time now. I had put in a new Be Cool radiator and had no issues with filling it or overflowing. I had to put another new radiator in due to switching over to a steering box. It is also a Be Cool radiator. I have vacuum filled it and after a few minutes the radiator builds up pressure and overflows. The coolant is cold. The upper hose is hot as well as the heater hoses. Was thinking maybe a pocket but vacuumed it several times to make sure. Thanks
I have a LS3 that I have in a 64 Impala. I have been building it for some time now. I had put in a new Be Cool radiator and had no issues with filling it or overflowing. I had to put another new radiator in due to switching over to a steering box. It is also a Be Cool radiator. I have vacuum filled it and after a few minutes the radiator builds up pressure and overflows. The coolant is cold. The upper hose is hot as well as the heater hoses. Was thinking maybe a pocket but vacuumed it several times to make sure. Thanks
TECH Fanatic
Joined: Feb 2015
Posts: 1,080
Likes: 178
The radiator was the only change? No engine changes? New rad plumbed the same as old?
Details of system:
old school radiator with pressure cap and overflow bottle or LS style system with sealed rad and surge tank with pressure cap?
cap pressure?
where are steam vents tied into on cooling system? Highest point on rad or highest point in cooling system?
Details of system:
old school radiator with pressure cap and overflow bottle or LS style system with sealed rad and surge tank with pressure cap?
cap pressure?
where are steam vents tied into on cooling system? Highest point on rad or highest point in cooling system?
Thread Starter
Launching!
Joined: Jun 2011
Posts: 244
Likes: 0
From: Walnut Creek, ca
The radiator is the only change due to switching over to a steering box.
No changes to the engine.
Everything is plumed the same way.
I am running old school cap and overflow with the same cap as before. Car has only been driven around the block a few times before the change.
The cap I believe is 15 PSI per Be Cool.
Steam vent is just under the upper radiator port on the radiator same as before.
No changes to the engine.
Everything is plumed the same way.
I am running old school cap and overflow with the same cap as before. Car has only been driven around the block a few times before the change.
The cap I believe is 15 PSI per Be Cool.
Steam vent is just under the upper radiator port on the radiator same as before.
Install an air bleed on one of your heater hoses. I have experience trapped air in a cooling system that’s very difficult to get, I used a bleed valve in the highest point of the system to get it out.
Thread Starter
Launching!
Joined: Jun 2011
Posts: 244
Likes: 0
From: Walnut Creek, ca
The first time I did it I lifted the car with my air bags then dropped the left side to get the fill neck at the highest point and got it out. I’ve tried that again but not sure if that’s it. I’ll try it again.
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TECH Fanatic
Joined: Feb 2015
Posts: 1,080
Likes: 178
The radiator is the only change due to switching over to a steering box.
No changes to the engine.
Everything is plumed the same way.
I am running old school cap and overflow with the same cap as before. Car has only been driven around the block a few times before the change.
The cap I believe is 15 PSI per Be Cool.
Steam vent is just under the upper radiator port on the radiator same as before.
No changes to the engine.
Everything is plumed the same way.
I am running old school cap and overflow with the same cap as before. Car has only been driven around the block a few times before the change.
The cap I believe is 15 PSI per Be Cool.
Steam vent is just under the upper radiator port on the radiator same as before.
Is rad cap/steam vent the highest point in system? If not, install a bleed at highest point. If so, it should self bleed any trapped air. Run engine with heater on and rpm >1500 ensuring sufficient water flow through out system. Use a rad neck adapter and funnel to help burb and fill the system to confirm no trapped air.
Maybe the new rad is restricted (something left in inlet tank during assembly, etc.). Simple rad flow test - drain and use shop vac exhaust to blow through rad core. Should be no restriction to air flow.