msm15

96 850T - 130k miles

The Coolant light went on recently on my 96 850T, i popped the hood to find out the resevour cap had busted (second time in 2 yrs) and the cooled basically spilled/boiled out.

I added more coolant and kept watch of the system and after about 20 minutes of idle the coolant level will raise from the low mark to the high mark and if I let it sit the pressure builds so much it start coming out of the broken cap - The extra pressure in the system caused the cap to bust.When i let it cool the coolant goes all the way down below the the bottom of reservour.

What am I looking at here - Head Gasket ??? - I have no coolant in oil, coolant is nice color, no overheating, and no white exhaust smoke - just way too much pressure in the coolant system - no I am not over filling it.


Basic history of the car: I picked it up for $700 after the original owner thought it had a bad head gasket cause of milk in the oil, he paid $1200 for the HG only to see the oil again 1 month later.
I suggested to him that it might be the PCV system at 109k which was never serviced, he still thought it was the gasket - so I got the car for $700

Long story short - I redid the entire PCV system and the problem went away, but I always had a small coolant leak, it could take weeks for the resevour to empty but I couldnt solve it, I changed the heater core which was bad, hoses, thermostat which was actually hollowed out open, radiator and other stuff along the way but there was always a small bead of coolant running down the side of the radiator and the ends of the hoses always looked swolen with coolant.

I am now thinking that when they did the gasket it wasnt a perfect job and there is a small leak. At this point I am looking to use one of those gasket sealants, its not worth it to me to pay $1000 for the HG job.

What are your thoughts.

Thanks