Hi all, i have an insignia 1.8 petrol, the other day i didnt screw my coolant cap down correctly and lost probably half of my coolant, stopped the car straight away, rang the misses to fetch coolant, filled up and away i went back home, since then my radiator fan has been on ever since, i have replaced the themostat including temp sensor and a new expansion tank, i have noticed that the coolant return pipe doesnt seem to be returning coolant correctly, any ideas?

 

Sounds like you have an air lock in the cooling system.
You'll need to work out where the air is (cool to touch when engine is at running temperature) and bleed it out

yes ive got a feeling your right, only thing is, i cannot get it to bleed off via the reservoir with the cap on or off, any ideas if theres a bleed screw on the insignia? tried googling but to no avail...🤔

 

Edited April 10, 20241 yr by Robbie L

ok so done more fumbling around and come to the conclusion that my head is completely drained, did so by partially removing the thermostat housing from the 4 long bolts to the head and not a drop, so this leads me to thinking its the water pump what has gone, so underneath is a pic of the pipe that leads from the pump to the thermostat housing, should coolant flow in the direction as arrowed?

Had the water pump off to be sure theres nothing wrong there, all is good, whilst at it ive found a bleed screw on the radiator, so at least i know my radiator is full, however i have still not been able to bleed the system fully, So the next thing is to buy a Vacuum refill kit so i can make sure there no air in the system as i fill it up.... really cant believe all the trouble im having!!!

The vacuum kit looks like it should do the job nicely and at least you'll know there is no air left in the system.
Check also the thermostat is not stuck closed but you should find that out if you can measure the temperatures before and after the stat with an infrared temp gun (very useful tool for many other jobs on a car - misfire, sticking brakes, etc)

Let us know how you get on with it 

Absolutely spot on, vacuum filled the system, got circulation flow back to the header...ran the motor for about 10 mins then the fan went off...no head damage either!!

 

Just need to keep an eye on it to see that it continues circulating

Thanks for letting us know the outcome