I have a volvo 760gle b28 (1984 december) which i purchased a month ago. The lady who sold it told me there was a gradual coolant leak but did not tell me where it was coming from. I have since checked the car and found that at times when the car is hot coolant is leaking from coolant resevoir cap through what appears to be a build up of heat and pressure.

Even though the coolant level appears to be empty just after running, in the mornings i find that the coolant level has risen in the resevoir ?

I was informed that the previous owner has also replaced all the hoses, the water pump and has replaced or reconditioned the radiator.

I am not sure that the radiator [part #1306173 (01398434)] is the correct one for this model. My car has a pressure cap of 75kpa. I am told the newer model 760s came with a 150kpa pressure caps. Could it be the wrong radiator or the pressure cap ?
Could someone please post their part number for their radiator ?

If the radiator on the car has been changed to a newer model is this safe and do i have to change the pressure cap? Can blow a gasket ?

I AM SURE IT IS LEAKING FROM THE COOLANT CAP. ( PRESSURE IS ESCAPING)

Any advice or possible explanations would be greatley appreciated.

Kind Regards
David