E30 M10 Cooling issues - Suspect head gasket?

[NZPED 2]

Hi All,

I've had a series of coolant leaks over the past month. I was hoping to find some advice/guidance as to what I should be looking for as a root cause of these issues. Initially I thought it the leaks were due to old age of the parts, now I suspect high pressure in the cooling system may be the culprit. Here's what happened.

1. Large puddles of coolant under the car. Small hole in radiator squirting out coolant, radiator was old so I replaced it.

2. With the new radiator in a new hole developed in one of the radiator hoses to the thermostat, replaced this hose.

3. Coolant is now coming out the coolant overflow hose in small quantities(~50ml under the car after it's been parked).

I have been driving the car daily, and it has only run hot (temperature gauge over halfway) on two occasions, both of which times the engine was under high load(steep hills) and I pulled over to prevent overheating.

Recently did an oil change, no trace of coolant in the oil and can't see any oil in the coolant when I take the radiator cap off.

Other than a leaking head gasket that is pressurizing the cooling system I can't think of what may have caused these issues.

I think my next step will be to go for a pressure test which would presumably identify a blown head gasket. Would anyone have an idea of the cost in getting one done and any garages to recommend?. Any other advice appreciated.

Thanks in advance.

[Eagle 1662]

Have you tested or replaced the expansion tank cap?

[NZPED 2]

I have tested the radiator cap(no expansion tank on this engine) by flipping it upside down, filling it with water and manually pressing in the spring. It seemed to work ok, was not jammed shut or anything.

[gjm 3258]

Could just be air in the system. Bleed it, then bleed it again.

[OP6 27]

You are not overfilling the radiator? 

[NZPED 2]

I quite possibly could be, I have been filling the radiator pretty much to the top.

Edited July 25, 2016 by NZPED