Radiator Cap ratings
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Race Director
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From: San Diego - Deep Within The State of CONFUSION!
Radiator Cap ratings
Even w/the High Efficiency core in mynew radiator, I'm having probs with it spitting into the overflow after a hot shutoff. The actual temp (Tested over and over again to verify the accuracy of the guage) is only 200 to 210 MAX. Never runs hot or overheats. But when I shut it down and leave it for a while coolant has bubbled into the overlfow bottle and then out the hose and over my newly painted engine compartment.
Why? I have bought new caps aftermarket, and still the third one gives same result. GM shows P/N 25679430 as the right cap for the car. Is this a 16 pound cap? That's what the radiator manufacturer recommends.
Next: can you explain to me why we're doing this???? :hat The radiator tube goes into the bottle. The cap on the bottle is a loose snap fit. Then the tube vents the bottle out onto the fenderwell.
It never appears to even fill the bottle yet always there is flow out the vent tube and onto the fenderwell. How does this happen?? :hat
Why? I have bought new caps aftermarket, and still the third one gives same result. GM shows P/N 25679430 as the right cap for the car. Is this a 16 pound cap? That's what the radiator manufacturer recommends.
Next: can you explain to me why we're doing this???? :hat The radiator tube goes into the bottle. The cap on the bottle is a loose snap fit. Then the tube vents the bottle out onto the fenderwell.
It never appears to even fill the bottle yet always there is flow out the vent tube and onto the fenderwell. How does this happen?? :hat
Safety Car
Joined: Aug 2000
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From: Clymer PA
Re: Radiator Cap ratings (SanDiegoPaul)
The deal is that when you shut the motor down the temperature will continue to rise to a certain point. There's really no harm in going with a higher pressure cap as long as your radiator can take the higher pressure (most likely your heater core won't be able to).
FYI I'm running a Moroso 19-21lb cap with my Be Cool Radiator and have no problems with it. It will start to spit some coolant into the overflow on hot days though.
FYI I'm running a Moroso 19-21lb cap with my Be Cool Radiator and have no problems with it. It will start to spit some coolant into the overflow on hot days though.
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From: San Diego - Deep Within The State of CONFUSION!
Re: Radiator Cap ratings (bence13_33)
Well the heater core is no longer. There are plugs in the water pump and the intake instead of heater hose connections. So no problem with the heater. As for the bottle, why does fluid come out the tube instead of filling the bottle?
The radiator mfgr has no problems with me using the higher cap. Where to find the ratings?
The radiator mfgr has no problems with me using the higher cap. Where to find the ratings?
Race Director
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From: Waterloo ontario Canada
Re: Radiator Cap ratings (SanDiegoPaul)
Are you sure you have the hoses right on the overflow bottle. The tube going into the overflow has a plastic pipe on it going all the way to the bottom of the bottle.
The overflow from the overflow bottle has NO tube in the bottle but connects to the very top of the overflow tank.
No fluid can possiblely overflow the tank with the overflow hose on the top.
Remember overflow from the rad goes into the port with the tube to the very bottom of the overflow tank and the tank overflow has no tube inside the tank.
The overflow from the overflow bottle has NO tube in the bottle but connects to the very top of the overflow tank.
No fluid can possiblely overflow the tank with the overflow hose on the top.
Remember overflow from the rad goes into the port with the tube to the very bottom of the overflow tank and the tank overflow has no tube inside the tank.
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From: San Diego - Deep Within The State of CONFUSION!
Re: Radiator Cap ratings (norvalwilhelm)
Remember overflow from the rad goes into the port with the tube to the very bottom of the overflow tank and the tank overflow has no tube inside the tank.
good point! Ya know, I never even thunk of checking them. Next time I drive her, I'll check it out.
Now, where to get the information on the PSI ratings of radiator caps by part number?
good point! Ya know, I never even thunk of checking them. Next time I drive her, I'll check it out.
Now, where to get the information on the PSI ratings of radiator caps by part number?
Melting Slicks
Joined: Jul 2002
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From: Deltona (son of Deland and DAYTONA) FL
Re: Radiator Cap ratings (SanDiegoPaul)
I've also read that leaking head gaskets or hairline cracks in the wrong places can cause a cylinder to pressurize a cooling system. I'm thinking that if the temp is not getting too hot but it's still putting too much fluid in the overflow tank that might be happening. Not sure how all that might happen, maybe some of the experts can ellaborate, or debunk it if what I read was not true.
