jdoyle

iTrader: (27)

I am testing my coolant system to see if any coolant is leaking from my heads into the combustion chamber so i figured what the hell.

From the pictures:

Can anyone tell me if my radiator cap is the stock, GM, radiator cap?

Also, could anyone who has tested their radiator caps look at my results after 20 minutes and see how it compares to their results? Looks like the cap passes the test to me since the gauge is in the 17 - 19 psi range and the cap says 18 psi on it.

How do you guys setup the pressure tester when you are checking the coolant system's pressure with the car running? There is no pumping involved like there is with the radiator cap, right.

I imagine that the process is:

1. Remove old cap
2. Put on tester cap.
3. Start car
4. When at full operating temperature, see where the gauge is, (meaning NO PUMPING)
5. Shut off car
6. Remove tester cap when car is cool, blah, blah, blah, etc.

Thanks for the help,
jdoyle

fleetmgr

Yep, stock

It's a good cap.

No, the whole idea of the pressure tester is so you can test the system COLD. Hook the tester to the radiator, pump it up, and watch it hold pressure (or not) just as you did with your cap. It's the only way you can see a pressure drop. If you do it with the engine running, you won't necessarily see a pressure drop even with a fairly substantial leak. Here's the scenario:
The engine comes up to temp, all looks good on the pressure gauge, but there IS a leak. As pressure starts to drop, some of the coolant will flash to steam, and this will tend to keep the pressure UP even though coolant level is falling. Or, in the case of a bad head gasket, you actually seriously over pressureize the cooling system with exhaust gasses.

Assuming that your system is completely full with no leaks, you should be able to pump it up and come back the next day with no pressure drop.

jdoyle

iTrader: (27)

fleetmgr, you are truly very helpful. Thanks for your input.