6R 1.2 TSI Coolant Issue
Posted: Sun Jun 30, 2024 5:18 pm
Bought car Aug 2023 and has been nothing but a headache, trying to pinpoint a coolant leak. Drove 2.5k miles this year. Quite a lengthy read but I would really appreciate if someone could come up with some suggestions as to what's going on!
Brief timeline:
Was leaking coolant cold when I bought it, could see a leak on the floor, got turbo coolant pipe changed the following month, did not fix it. Would do for a drive and quickly loose all the coolant. Replaced water pump on the 3rd of October, still no difference. Took it back to the garage the following day and told me the fan is not kicking in, so they changed a sensor (do not know what sensor), and then this made me lose coolant much slower-NOTE: I still have never heard or seen the fan kick in!
From having to top it off after a 30 minute drive, I would now get a warning to top it up every 200 miles after these 3 changes. However I am obviously frustrated the issue was not solved and didn't take it back to the garage. There was also no more visible leak on the floor!
Drove like this for months with no problem, apart from an occasional oil light which resolved when I opened the cap. Of note, the dipstick showed it was overfilled. Changed oil to bring it back to half on the dipstick in April, however it rose back over maximum within a week and I would carry on getting the oil light each month.
In June 2024 this year, 8 months since the repairs got car serviced by a "German specialist", and got the leak diagnosed too. They said at first the water pump was leaking and not allowing the coolant through or something because it was aftermarket, and I told them I would get it replaced by the first garage who changed the water pump. After saying this, they said they were gonna keep my car and run some further tests and 4 days later came back and said they found a small leak in the charge air cooler intercooler. Said coolant leaking out of the cooler into the exhaust manifold, causing white smoke and rough idling and if I continue to drive on this it will blow my gasket. Quoted me £650 to replace, to which I took it to another garage and changed it for £440, part from TPS.
However, now the car leaks coolant much faster, though not as fast as it did back when I bought it, no leaks when not running and nothing on the floor. The only place where I seem to be losing coolant is through the expansion tank overflow valve, as when I fill it up back to max, sometimes I noticed it coming out the gap. I tried changing the cap to a new one but it made no difference. One positive is that the oil level has remained constant, so potentially the charge cooler repair solved this?
What do I think is going on?
Car when cold, I fill the coolant up to maximum. I start the car and the coolant level goes down slowly, I guess that is the valves opening, air getting in somewhere or a leak from somewhere when the engine is on? Can anyone give their verdict?
I drove the car for more than an hour, and this time I got the red coolant light and beeping noise, so I stop and check the levels and the coolant is well above the max level and burning. I am confused by this because the car has left a trail of coolant and coolant is dripping out of the overflow valve in the tank. So I think maybe something is not cooling the coolant properly, causing it to come out of the expansion tank, but this doesn't make sense because sometimes when I fill the coolant, it leaks out the overflow tank valve even in the morning after leaving it overnight: it is completely cold! When the levels decrease, I find opening the cap to burp it brings the levels higher, but then driving it again makes it go lower again, is this the system becoming pressurised?
So the issue I have is coolant levels dropping, no sign of the fan working, and on long drives the coolant levels rising alot and coming out the tank. No visible leak and garages say it's holding pressure. Done a head gasket test and it was negative. I think maybe something is wrong with the water pump or maybe the thermostat or another mechanism/sensor not opening up at the correct temp, causing a back flow of hot coolant out the tank valve.
Brief timeline:
Was leaking coolant cold when I bought it, could see a leak on the floor, got turbo coolant pipe changed the following month, did not fix it. Would do for a drive and quickly loose all the coolant. Replaced water pump on the 3rd of October, still no difference. Took it back to the garage the following day and told me the fan is not kicking in, so they changed a sensor (do not know what sensor), and then this made me lose coolant much slower-NOTE: I still have never heard or seen the fan kick in!
From having to top it off after a 30 minute drive, I would now get a warning to top it up every 200 miles after these 3 changes. However I am obviously frustrated the issue was not solved and didn't take it back to the garage. There was also no more visible leak on the floor!
Drove like this for months with no problem, apart from an occasional oil light which resolved when I opened the cap. Of note, the dipstick showed it was overfilled. Changed oil to bring it back to half on the dipstick in April, however it rose back over maximum within a week and I would carry on getting the oil light each month.
In June 2024 this year, 8 months since the repairs got car serviced by a "German specialist", and got the leak diagnosed too. They said at first the water pump was leaking and not allowing the coolant through or something because it was aftermarket, and I told them I would get it replaced by the first garage who changed the water pump. After saying this, they said they were gonna keep my car and run some further tests and 4 days later came back and said they found a small leak in the charge air cooler intercooler. Said coolant leaking out of the cooler into the exhaust manifold, causing white smoke and rough idling and if I continue to drive on this it will blow my gasket. Quoted me £650 to replace, to which I took it to another garage and changed it for £440, part from TPS.
However, now the car leaks coolant much faster, though not as fast as it did back when I bought it, no leaks when not running and nothing on the floor. The only place where I seem to be losing coolant is through the expansion tank overflow valve, as when I fill it up back to max, sometimes I noticed it coming out the gap. I tried changing the cap to a new one but it made no difference. One positive is that the oil level has remained constant, so potentially the charge cooler repair solved this?
What do I think is going on?
Car when cold, I fill the coolant up to maximum. I start the car and the coolant level goes down slowly, I guess that is the valves opening, air getting in somewhere or a leak from somewhere when the engine is on? Can anyone give their verdict?
I drove the car for more than an hour, and this time I got the red coolant light and beeping noise, so I stop and check the levels and the coolant is well above the max level and burning. I am confused by this because the car has left a trail of coolant and coolant is dripping out of the overflow valve in the tank. So I think maybe something is not cooling the coolant properly, causing it to come out of the expansion tank, but this doesn't make sense because sometimes when I fill the coolant, it leaks out the overflow tank valve even in the morning after leaving it overnight: it is completely cold! When the levels decrease, I find opening the cap to burp it brings the levels higher, but then driving it again makes it go lower again, is this the system becoming pressurised?
So the issue I have is coolant levels dropping, no sign of the fan working, and on long drives the coolant levels rising alot and coming out the tank. No visible leak and garages say it's holding pressure. Done a head gasket test and it was negative. I think maybe something is wrong with the water pump or maybe the thermostat or another mechanism/sensor not opening up at the correct temp, causing a back flow of hot coolant out the tank valve.
