radiator cap failure

[Kain]

i have a 16 lb cap that doesn't like to seal after replacing it with 3 other caps of different brands. will it hurt to put a 20 lb cap on it?
It would lose enough fluid to be a quart or two low out the overflow.
im trying to stop that.

 

[paratrooper307]

i have a 16 lb cap that doesn't like to seal after replacing it with 3 other caps of different brands. will it hurt to put a 20 lb cap on it?
It would lose enough fluid to be a quart or two low out the overflow.
im trying to stop that.

A higher pressure cap raises the boiling point and may help prevent coolant loss, but it's generally not necessary or advisable to exceed the factory pressure specifications. If a 16 lb cap isn't sealing, you may have another problem, namely the flange on the radiator being bent or damaged, or the cap being in poor condition, or a pressure loss in the system. An auto parts store may let you rent a cooling system test kit, so you can determine where your problem is.

 

[Kain]

Well i just had it at the rad shop here in town,but ill look into it

 

[4X4HIGH]

Do you have an overflow bottle or a recovery tank? There is a difference between the two and they each use a different cap.

 

[Kain]

Plastic overflow

 

[Kain]

could it be i have the diesel rad and they are selling me the wrong cap

 

[4X4HIGH]

could it be i have the diesel rad and they are selling me the wrong cap

If you just ask for a radiator cap for a given vehicle that uses a recovery system (most have been recovery systems for years) and you have an overflow tank NOT a recovery tank then you are getting the wrong cap every time. You need to go in and ask for a cap for an overflow system and for whatever pressure you need (16 psi is the most common).