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Testing testing!

How is a pressure test done and for how long should the system be pressurized !

Pressure test on what?

Cooling system? Cylinder compression?

You have to provide more detail. You haven’t given us much to work with.

Cooling please…

It’s kinda like taking your blood pressure. You get a pressure tester, remove the radiator cap (only when the engine is COLD and the car has not been driven for several hours), put the pressure test cap on instead, pump it to whatever the manufacturer spec for your system is (if you can’t find that, just do 10psi or so), and then wait to see if the pressure drops. If it loses more than a couple of psi over 2-3 minutes you probably have a leak. Repressurize it and inspect all the hoses, radiator, etc, for leaking fluid.

Um, I’m still not sure if Kbear60 wants the engine cooling system checked, or the passenger cooling system (i.e. the AC) checked.

Kbear60, what sort of problems are you having?

Oh, yes, I assumed engine cooling system.

The air conditioning pressure - - if you have to ask how to do it, take it to a shop.

For the engine cooling system, I usually pump it to the maximum pressure listed on an underhood sticker or, if that is not available, 15 psi. If you can watch the needle on the gauge drop, you have a significant leak and should start looking. These devices can be your best friend for finding elusive coolant leaks. Ideally, you should never lose any pressure if the system is leak-free, but I consider a pressure loss of less than a pound in ten minutes to be negligible.

I was looking for coolant system… Ok … If the is small should it take over night to find out it leaks?


Are you having a specific problem we could help you with, or is this theoretical?

If the cooling system pressure test passes I replace the radiator cap with a new one. That’s where a lot of pressure leaks come from anyway. It’s cheap insurance.

My prolbem was my system was overheating Just on certain days… When it was hot… 4 tests later fund it was a head gasket leak…

Is that normal?

One Of The Censequences Of Over Heating, Particularly If It Continues Beyond One Episode, Is Head Gasket Failure. What Starts Out As One Part Of The Cooling System That Fails, Or Low Coolant Level, Can Turn Into A Head Gasket Failure.


With a special adapter you can also check the cap. They commonly fail unable to hold the recommended pressure.


Thanks for the help…