I've had my Sierra for about 5/6 month and when I picked it up the heater matrix was leaking badly and there was a small leak from the radiator (which only seemed to be intermittent). So I disconnected the matrix and looped it off, I then flushed the rad filled the engine with coolant and chucked a K-seal in to seal the radiator. This all worked fine! The rad fan switch was also fubar'd and one of the two fans is jammed, I'm now running the single fan off a switch on the dashboard.
Right the problem are..........
The coolant level fluctuates sometimes it comes up to the max mark sometimes there is literally nothing left in the expansion tank, but it's not loosing coolant as it'll go up and down. Usually the coolant will return to maximum if the expansion tank cap is removed and the pressure is released.
Also the coolant system seem to hold pressure for ages even when stone cold, you leave it for say 2 days undo the cap and it seems to release lots of pressure
I've put a new cap on it to see if it would cure it but no difference.
A mate of mine suggested it might be a blocked thermostat, I took mine out to find it was jammed a little bit open but wouldn't open fully or close fully. I removed it just before a drift day to make sure the car didn't overheat. But again no difference!
Also foam appears in the header tank sometime when the car has been driven hard. When I got back from RRG11 I could smell a strong smell of coolant, I opened the bonnet to find foam erupting from the expansion tank.
I would have thought that all of this stuff would point toward head gasket failure? But the car doesn't over heat, doesn't seem to be low on compression (i.e. performance seems good) and it doesn't seem to actually uses coolant. Any ideas?
Right the problem are..........
The coolant level fluctuates sometimes it comes up to the max mark sometimes there is literally nothing left in the expansion tank, but it's not loosing coolant as it'll go up and down. Usually the coolant will return to maximum if the expansion tank cap is removed and the pressure is released.
Also the coolant system seem to hold pressure for ages even when stone cold, you leave it for say 2 days undo the cap and it seems to release lots of pressure
I've put a new cap on it to see if it would cure it but no difference.A mate of mine suggested it might be a blocked thermostat, I took mine out to find it was jammed a little bit open but wouldn't open fully or close fully. I removed it just before a drift day to make sure the car didn't overheat. But again no difference!
Also foam appears in the header tank sometime when the car has been driven hard. When I got back from RRG11 I could smell a strong smell of coolant, I opened the bonnet to find foam erupting from the expansion tank.
I would have thought that all of this stuff would point toward head gasket failure? But the car doesn't over heat, doesn't seem to be low on compression (i.e. performance seems good) and it doesn't seem to actually uses coolant. Any ideas?
