Overheating/fluctuations with vintage air. - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**pound41** · 08-11-2015, 10:09 PM

I recently bought my son an s10 blazer. it ran hot but didnt spike. I noticed the radiator had been replaced and the top hose would bulge and seep. Ok its the thermostat. Replace the therm and top hose. Same thing runs hot. the temp comes down when you switch from ac to heat. It has to be the original water pump. Replace the water pump. It instantly spikes running hotter than it ever did. The overflow tank is now full. I slightly crack the radiator cap. The top radiator hose starts to make a reching sound and move. It was a lot of air. After that started it up and it runs cool. I saw a show on TV.Newly restored hot rod. Same problem. They had a special radiator cap that had one hose for liquid going in and another for air going out

bamachem · 08-12-2015, 09:08 AM

Quote:

Originally Posted by pound41

I recently bought my son an s10 blazer. it ran hot but didnt spike. I noticed the radiator had been replaced and the top hose would bulge and seep. Ok its the thermostat. Replace the therm and top hose. Same thing runs hot. the temp comes down when you switch from ac to heat. It has to be the original water pump. Replace the water pump. It instantly spikes running hotter than it ever did. The overflow tank is now full. I slightly crack the radiator cap. The top radiator hose starts to make a reching sound and move. It was a lot of air. After that started it up and it runs cool. I saw a show on TV.Newly restored hot rod. Same problem. They had a special radiator cap that had one hose for liquid going in and another for air going out

Also, if the air bubble gets trapped at the thermostat, it can cause the thermostat to close, creating dangerous temp spikes. When it comes to cooling systems, air is the devil! LOL

Smokey burnouts · 08-12-2015, 01:56 PM

Quote:

Originally Posted by bamachem

Also, if the air bubble gets trapped at the thermostat, it can cause the thermostat to close, creating dangerous temp spikes. When it comes to cooling systems, air is the devil! LOL

Yeah I drilled 2 small holes in thermo to hopefully avoid the issue of trapped air

Ole Beater · 08-13-2015, 11:30 AM

You should check to see if your bottom radiator hose is collapsing when the engine rpm's are up. Check the hose to be sure the spring is in it.

Ole Beater · 08-13-2015, 05:22 PM

Another problem could be the fan clutch, if it still has one on it.

08-11-2015, 10:09 PM	#26
pound41 Registered User Join Date: Dec 2002 Location: Northern Virginia Posts: 1,269	Re: Overheating/fluctuations with vintage air. I recently bought my son an s10 blazer. it ran hot but didnt spike. I noticed the radiator had been replaced and the top hose would bulge and seep. Ok its the thermostat. Replace the therm and top hose. Same thing runs hot. the temp comes down when you switch from ac to heat. It has to be the original water pump. Replace the water pump. It instantly spikes running hotter than it ever did. The overflow tank is now full. I slightly crack the radiator cap. The top radiator hose starts to make a reching sound and move. It was a lot of air. After that started it up and it runs cool. I saw a show on TV.Newly restored hot rod. Same problem. They had a special radiator cap that had one hose for liquid going in and another for air going out

08-13-2015, 11:30 AM	#29
Ole Beater Registered User Join Date: Oct 2011 Location: St Petersburg, Florida Posts: 154	Re: Overheating/fluctuations with vintage air. You should check to see if your bottom radiator hose is collapsing when the engine rpm's are up. Check the hose to be sure the spring is in it.

08-13-2015, 05:22 PM	#30
Ole Beater Registered User Join Date: Oct 2011 Location: St Petersburg, Florida Posts: 154	Re: Overheating/fluctuations with vintage air. Another problem could be the fan clutch, if it still has one on it.



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