Why does Radiator Overflow Bottle Boil?
Thread Starter
Drifting
Joined: Aug 2005
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From: Hamilton NJ
Why does Radiator Overflow Bottle Boil?
Team,
I managed to get the stat housing for my '79 on and not leaking
!! I topped it off with coolant and ran it and all seemed well. I have added a thermostat (195 F) in the housing,which was not there when I bought it back in August. Today I took it for a spin and after I parked and stopped the engine the overflow bottle was "boiling". Is this massive air/vacuum being generated or is it legitimately way too hot? It was running in the normal operating range when I was driving?
Otherwise all is well...60 degrees and sunny in central jersey in January is OK by me.
Steve
I managed to get the stat housing for my '79 on and not leaking
!! I topped it off with coolant and ran it and all seemed well. I have added a thermostat (195 F) in the housing,which was not there when I bought it back in August. Today I took it for a spin and after I parked and stopped the engine the overflow bottle was "boiling". Is this massive air/vacuum being generated or is it legitimately way too hot? It was running in the normal operating range when I was driving?Otherwise all is well...60 degrees and sunny in central jersey in January is OK by me.
Steve
Le Mans Master
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From: Austin Texas
Originally Posted by Wuttin
What's recommended? 180 F?
Le Mans Master
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From: DFW TX
Cruise-In VII Veteran
St. Jude Donor '07
You guys a 79 is recirculating. It is normal. It lets the hot water expand and when the radiator cools it pulls it back in. Make sure you have the right cap also.
Thread Starter
Drifting
Joined: Aug 2005
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From: Hamilton NJ
Originally Posted by Budman78
You guys a 79 is recirculating. It is normal. It lets the hot water expand and when the radiator cools it pulls it back in. Make sure you have the right cap also.
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Le Mans Master
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From: DFW TX
Cruise-In VII Veteran
St. Jude Donor '07
On a 79 you have to make sure there is water in the recirculating tank. When colding the radiator will pull air from the tank instead of liquid.
Over the years, alot of owners and shop would replace the caps with an over-heat style and usually kill the system. Check your manual for operating temp range of the radiator cap.
Also, buy the thermostat that has the bleed hole in it. It's usually about $2 more. Check your electric fan in the front and make sure it's working. I believe all 79's had them. And also check to make sure your radiator seals are in place.
Over the years, alot of owners and shop would replace the caps with an over-heat style and usually kill the system. Check your manual for operating temp range of the radiator cap.
Also, buy the thermostat that has the bleed hole in it. It's usually about $2 more. Check your electric fan in the front and make sure it's working. I believe all 79's had them. And also check to make sure your radiator seals are in place.
Team Owner
Joined: Aug 1999
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From: Ontario
The only thermostat listing in the GM parts book for a 1979 is 195*. The auxiliary electric fan was an option in 1979 so do not be dismayed if you do not find one.
I suspect that you did not fill the coolant tank to the COLD mark. Thus you are getting coolant at engine temps and under 15psi pressure coming over from the rad. That can certainly be above 212*F. If the coolant tank is filled to the proper level the relatively cool fluid in it will mix with the engine spillover and prevent boiling.
I suspect that you did not fill the coolant tank to the COLD mark. Thus you are getting coolant at engine temps and under 15psi pressure coming over from the rad. That can certainly be above 212*F. If the coolant tank is filled to the proper level the relatively cool fluid in it will mix with the engine spillover and prevent boiling.
Thread Starter
Drifting
Joined: Aug 2005
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From: Hamilton NJ
Purging air from Radiator??
Originally Posted by big_G
195 degree thermostat is fine. Bubbling in the overflow usually means that the engine is overheating, possibly due to air pockets in the system. Also you need to be sure the radiator cap is good, holding 15 psi.
Thanks,
S
Team Owner
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From: eville in
Originally Posted by paul67
The only thermostat listing in the GM parts book for a 1979 is 195*. The auxiliary electric fan was an option in 1979 so do not be dismayed if you do not find one.
I suspect that you did not fill the coolant tank to the COLD mark. Thus you are getting coolant at engine temps and under 15psi pressure coming over from the rad. That can certainly be above 212*F. If the coolant tank is filled to the proper level the relatively cool fluid in it will mix with the engine spillover and prevent boiling.
I suspect that you did not fill the coolant tank to the COLD mark. Thus you are getting coolant at engine temps and under 15psi pressure coming over from the rad. That can certainly be above 212*F. If the coolant tank is filled to the proper level the relatively cool fluid in it will mix with the engine spillover and prevent boiling.
Le Mans Master
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From: Austin Texas
Originally Posted by Wuttin
How does one purge the air from the radiator? Is it kosher to start the car with the cap off of the radiator or should purging happen by taking the cap off of the overflow bottle?
Thanks,
S
Thanks,
S
Team Owner
Joined: Jul 1999
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From: Huntersville NC
Where is that disclaimer when we need it? Before removing the radiator cap make sure the engine is entirely cooled off. Maybe let it sit overnight. Never remove the radiator cap when engine is hot, it can still be hot an hour after you turn it off There, is that disclaiming enough? Should be ok to start the engine with the cap off. 
Le Mans Master
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From: Austin Texas
Originally Posted by PRNDL
Where is that disclaimer when we need it? Before removing the radiator cap make sure the engine is entirely cooled off. Maybe let it sit overnight. Never remove the radiator cap when engine is hot, it can still be hot an hour after you turn it off There, is that disclaiming enough? Should be ok to start the engine with the cap off.
If it's too hot to keep your hand on it, don't remove it 'till it cools off.
Thread Starter
Drifting
Joined: Aug 2005
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From: Hamilton NJ
Originally Posted by paul67
The auxiliary electric fan was an option in 1979 so do not be dismayed if you do not find one.
Is there an easy way to test it so I can make sure it is working?
When should I expect it to kick on?
TTFN
