GM's Redesigned 2003+ LIM gaskets

[david3100]

Too much pressure?

I'm beginning to suspect that the pressure cap on the radiator needs to be less considering the nylon/rubber design. That's not the case universally since the one I'm doing now was obviously not torqued according to updated procedure and is cracked on the ends. What's your opinion of the pressure cap suspicion?

[IsaacHayes]

Eh, nope, from all the one's I've seen the plastic is warped from heat and allows the rubber/silicone gasket material to walk away from the ports and that causes a leak. The real old ones the plastic gets brittle (not from over torquing) from age and just turns to ash in your hands. The first one I did on my car even the intake ports were warped and leaking causing vacuum leaks.

I've over filled my coolant before and it will squirt out of the overflow tank so I don't think the cap is too tight. You just turn it until it clicks and that's it. On older caps you might not feel the click, so if you don't know how far to turn it by feel then get a new cap.