How long for wait before opening hot radiator drain ?
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Joined: Jul 2014
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From: Reno NV
How long for wait before opening hot radiator drain ?
I am flushing my C5 coolant. How long should it take for a hot car to cool so that its safe to open the surge tank and radiator draincock ? Thanks guys.
Racer
Joined: Nov 2006
Posts: 297
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From: San Jose California
Like many things in life, It Depends
The pressure cap allows coolant (half dexcool and half distilled water) to NOT boil until over 230 F (at sea level). You could be SCALDED if you attempt to 1/2 turn (NOT completely open) the radiator cap within 10 minutes of a boil over. Wait until the hissing stops before carefully open the Pressure cap the rest of the way.
Melting Slicks
Joined: Apr 2009
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I agree with comments above. The design of the radiator overflow cap keeps you pretty safe as long as you open it very slowly allowing for the air pressure to escape before you open it completely. Just make sure you put a rag over it when doing it.
Le Mans Master
Joined: Mar 2011
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From: Columbia SC
For normal flushing I would wait 30 minutes and like he said use a towel or thick rag on the cap to release the tank pressure. ! hour if you had a boil over issue of some type. When I flush my car systems I just do it over several days and drain and refill in the morning when I know everything is cold.
Safety first, you are not on the side of the road trying to get home. I also have safety glasses in all my cars in case of an emergency. I have had to refill at least one car on the side of the road. Suggest you use a pair if you are doing your work hot.
Safety first, you are not on the side of the road trying to get home. I also have safety glasses in all my cars in case of an emergency. I have had to refill at least one car on the side of the road. Suggest you use a pair if you are doing your work hot.
Last edited by dadaroo; Oct 28, 2014 at 10:49 AM.
Racer
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you can do it while still warm if you loosen the radiator drain plug first, that will release the pressure in the system and then you can remove the cap... just use common sense while draining it and you will be fine, meaning don't stick your face right in front of the drain plug while loosening it
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From: Washington Michigan
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