cooling system pressure?

[924runnerSR5]

hey guys. quick question. my cooling system will not lose its pressure when it cools off. i ran the truck and then came back 2 days later with out running it and when i took the rad cap off coolant spued out because it was still under pressure. does anyone know why its doing this?? its a 92 v6 5speed.
help is appriceated.
ty much

 

[turboSR5]

Replace the radiator cap with the correct one for your model/year as a starting point.

 

[924runnerSR5]

Replace the radiator cap with the correct one for your model/year as a starting point.

the one that is on there is one that i bought from toyota and gave them the year make and everything. and if its not de-pressurising is it a bad thing??

 

[turboSR5]

Yeah, it could be a bad thing. Most cooling systems are designed to operate below a certain PSI, the cap is designed to relieve pressure at a certain PSI. If the cap isn't letting off the pressure you can blow hoses, gaskets etc..

 

[Redneck92]

Check to see if the spring on the bottom of the cap is free, and also check to see if the overflow at the cap is blocked by something. I think thats the first time I have ever heard of a system keeping pressure rather than not holding it.