radiator pressure

[carl christensen]

is it normal after shuting off the truck for coolant to escape in to the reservoir tank..1983 ford f350 diesel with a aprox 92 7.3 idi..13 lb cap

 

[IDIBRONCO]

We need a few more details in order to answer this. How much coolant goes into the overflow? Does it ever over fill the reservoir? Does it only do this after shutting the engine off or does it do this all the time? How fast does the coolant go into the overflow? Is it only coolant or are there a lot of air bubbles forming in the overflow? Does the coolant pull back into the radiator when the engine cools off? Is the engine running hot? Are you using the factory gauge or an aftermarket gauge to determine the engine temperature? Sorry for this, but it was a vague question.

 

[carl christensen]

well ive got a real good aftermarket guage , truck does not overheat.i just noiticed it burping back in to the tank after shut down ..no air bubbles...no water in oil visa versa, after cool down it apears to suck some coolant back into radiator...iam going to drive this for awhile to see how much coolant goes i nto overflow..and get a oem cap

 

[IDIBRONCO]

In that case, it sounds like it's normal. Talking only about an engine that's at operating temperature, after you shut the engine off, The coolant actually gets warmer/hotter for a while. When the engine's running, the coolant absorbs heat from the engine and then sheds that heat in the radiator. Since the coolant's no longer flowing after the engine's shut off, it will still absorb heat from the engine, but it can't get rid of that heat. The cylinders and especially the heads (around the combustion chambers) are hotter than the coolant is so the coolant will still absorb the heat until everything is at the same temperature. Then, over time, the heat will transfer from everything to the air and it will all cool down. Since the coolant still gets hotter after the engine's shut off, it will build more pressure in the cooling system. Often this will be enough to make the radiator cap open and let some coolant into the overflow. As the coolant cools off, it will draw back into the engine/radiator from the overflow. I hope this helps you understand what's happening.

 

[carl christensen]

thank you

 

[IDIBRONCO]

You're welcome.