Mystery coolant problem
I have a 99 Olds Cut. 3.1L chevy V6. It had a lower intake manifold leak. I took everything apart and replaced the seals, replaced the water pump, replaced the thermostat, changed the oil... put everything back. Then I filled it with coolant, drove it for a little bit, put more coolant, blead the system till pure coolant came out of the bleeder... Then drove the car over 50 miles. Temp gauge was still good until I pulled in my driveway and shut it off it all boiled right out of the resivior cap. This also happened prior to me changing the seals and I thought that changing the seals would do the trick.
I'm not sure if the cap is bad, it was changed not too long ago but this is the third or fourth time this happend. I'm not sure if its the radiator or maybe the heads. Maybe I didn't bleed the system as good as I should have. I'm not a mechanic but I took the time to read the manual and get some help from a mechanic. I cannot figure out whats causing this to happen. I have used the search and didn't really pull up anything to really help me solve the problem.