Evening all, need to pick your brains
So as most of you have seen the last few years I’ve been having issues with keeping my coolant in my engine bay
but i’m Starting to run out of ideas now.
So after at lot of diagnosing and running tests I found that the only thing I could find was my head pressures were all over the place. I decided on replacing the head, head skimmed and valves lapped lovely jubbly.
New timing belt, tensioner, head gasket, water pump etc etc.
So today I was doing the last finishing bits before I could run it, head pressures are 140 on all four cylinders.
Started the car and after 5-10 mins coolant was over flowing out of the expansion tank but the fan didn’t cut in once, so checked all the pipes and topped up again with coolant and started it up but this time I switched the fan on manually. It sat there running for 25 -30 mins not a problem, I was going round with a laser temp gauge checking pipe temps and they were all between 50 - 70’c and thermostat was around 88 ish. I thought sweet it’s all ok, I then switched the fan off and with 3 mins coolant was flowing out the expansion tank again.
As soon as I switched it off I checked the coolant temp in the tank and it was around 40 -50’c. It’s not really boiling over it just seems to find this pressure when the fan was switched off.
I’m just wondering if you guys had any ideas or came across this as I’m at a loose end