Cooling system operating pressure

[Grumpy6L]

Does anybody know the cooling system operating pressure

I am wanting to pressure test my 6.0L after it got a bit hot the other day, want to make sure I haven't cooked anything other than the overflow resevoir.

Cheers

[Crazy Paul]

Cooling System Leak Test is done to maximum of 130kPa.
130 kilopascal = 18.8 pound/square inch

Normal operating pressure will be lower than that, maybe something is written on your radiator cap.

[american_kestrel]

GM SI Database says the radiator cap is rated at 15 psi when it starts relieving excess pressure. But testing procedures for the cap say to pressurize the cap (removed from radiator) 17-22 psi to test it works. I'd say between 15-22 psi.

[american_kestrel]

I missed CrazyPaul's post while I was looking it up. What he said considering what I found in GM (SI) Service Info.

[Grumpy6L]

Yeah roger that, was reading the service manual it says max press 130kpa

Then low an behold the rad cap says 120kpa, might test it at that eh!

Cheers mate

[Crazy Paul]

GM SI Database says the radiator cap is rated at 15 psi when it starts relieving excess pressure. But testing procedures for the cap say to pressurize the cap (removed from radiator) 17-22 psi to test it works. I'd say between 15-22 psi.

Ummm NO.

Max cooling system operating pressure will be 15psi.
Max test pressure of the entire cooling system in the car will be 18.8psi.

(Going to 22 psi to test the function of the cap relief [when isolated from the car] does not mean the entire cooling system can handle anything more than 18.8psi).

[Grumpy6L]

Tested at 120kpa (17.4psi) all seems good, bit of a ghost in the machine I think.

Tad worrying as thermos didnt work the other day, checked all relays and fuses, tested thermo fan motors - nothing?

Replaced thermostat today, ran it up, then gave it a bit of a flogging, fingers crossed.

If anyone has come across something similar to this please let me know, if it hadn't of been sitting in the drive way at home when it got hot might have been a different outcome.
Thanks for ya help peoples.