Diagnose and Conquer Master the Fix for a Radiator Cap That's Losing Pressure

Confirm the rim is polished clean. Unlike for Miata thermostats, I find aftermarket radiator caps OK. Check the hose to the radiator's external ... There is no valve in the radiator cap that permits only gases or vapors to pass and not liquids. If the cap is not sealing, there is a pathway ... If you can get it clean and dry you can temporarily fix it using two part steel epoxy putty. Mix the putty well and roughen the area with coarse ... What I do a few times a week is open my radiator cap with the engine running, top it off with premix 50/50, and let it run. Initially, I had ... You can try pushing down hard on the cap and turning it by hand to see if it will release and if not then try the channel locks while pressing ... Usually what happens is they won't hold pressure. It is possible that the vent is plugged up. But there only suppose to vent in case of a ... The radiator cap allows pressure to build up in the cooling system and will eventually vent that pressure to the overflow bottle as the need arises. SRPWR wrote: Inside the filler neck on the rad. There is a lip about 3/4 inch down that the rubber O ring on the rad cap sits on. My car would ... My radiator cap is original, have had no problem in 3 years, WITH coolant. ... Changing the radiator cap won't make a bit of difference. Either ... Maybe try spraying some soapy water around the connection of the tester to the radiator. Another thought is to put the cap back on and run it up ...