Mystery Antifreeze Loss

[RS1979]

I've got a 2002 Ranger with a 3.0L. I keep having to add antifreeze to it. There are no leaks, no antifreeze in the oil and no white smoke coming from the exhaust. When the level drops, it does run hot but when I top it off again it cools back down. Any ideas?

Thanks
Brett

 

[Dirtman]

How old is your radiator cap? It could be weak and allowing the coolant to boil off.

 

[RS1979]

I couldn't tell you. If that were the case, wouldn't antifreeze leak on the ground when I parked it? I did have a pressure test done an it held pressure

 

[Uncle Gump]

You won't have a visible leak if the coolant escapes in the form of steam.

Pressurizing the cooling system raises the boiling point... this is done with the radiator cap.

 

[Dirtman]

A pressure test tests everything except the cap. If the cap is weak it allows coolant to boil, the steam then flows to the overflow tank and simply evaporates. The air in the system also causes the temp to shoot up. A cap cost 10 bucks, if its original it should be replaced anyway.

 

[RS1979]

Good info Dirtman. I'll give it a try. Definitely can't hurt. Thanks buddy

 

[Royjohnbutch]

I've got a 2002 Ranger with a 3.0L. I keep having to add antifreeze to it. There are no leaks, no antifreeze in the oil and no white smoke coming from the exhaust. When the level drops, it does run hot but when I top it off again it cools back down. Any ideas?

Thanks
Brett

It might be your water pump is leaking, it will only leak at highway speeds, mined leaks a little, I keep track of the level of antifreeze I need to change it , it’s pretty invor task

 

[Bird76Mojo]

One thing to check/eliminate.. Look at the underside of your oil fill cap. See any snot?

 

[RS1979]

Not even a booger. LOL