I haven't drove my truck since friday, when I got home tonight I noticed a small puddle of antifreeze on the ground. I looked around and thought well it must be the sending unit for electric fans I installed last weekend. while I was in the process of checking that with one hand I was loosening my radiator cap with my other and it let out pressure like it was opened at 250 degrees. Why? and I still cant find where it is leaking at. (could have been alittle easier to check for leak if engine wasnt covered in antifreeze. You finish one thing and its time to fix another. thanks

 

Not a clue! Most pressure you should have is whatever the radiator cap is rated at. Even then, it should be gone after sitting all weekend.

 

ya I know, you would think it would be gone. I think it built so much pressure that it made a leak behind water pump somewhere. I ran truck in driveway last night and let it get hot and shut it off, no antifreeze on ground this morning and no pressure in hoses. i will check again tonight. thanks

 

AJHeating,

Is your radiator overflow tube still connected to the reservoir? Just thinking...

 

Ya and it is working fine too. I guess it would have to be in the radiator cap not releasing the pressure.

 

The reason I was asking... sometimes, when one opens the fuel tank you hear a loud swooshing sound. Usually this is pressure escaping, but can be a vacuum [negative pressure] drawing in air. Since the pressure in a radiator is caused by temperature, which cannot exceed the rating of the radiator cap [if it is functioning properly], the pressure should go back to the starting point [very little or none] once the engine and radiator cools. However, if the overflow hose was pinched, such that the hot coolant could not vent, then perhaps a vacuum could develop as the components cooled??

 

thank you for the advice. the hose isnt pinched but that is a good Idea. I think I am going to replace that hose tommorow. I got home tonight and checked the pressure again and there was enough pressure to overflow again.