Golf mk2 Gti

[Schalke04]

Checked a few things and have no idea what fixed it. Now another problem I've been having is the car keeps over heating. Water pump seems fine, impeller doesn't seem to be lose. Thermostat works. Got a new overflow tank cap. Have been searching forums and can't figure it out. Car drives fine and doesn't seem to have any water in the oil, or oil ok the water. So hoping it's not head gasket. Anyone have any ideas?

[Bamish1000]

Air trapped in the system? Takes are fair effort to get all the air out of these.

[Schalke04]

Air trapped in the system? Takes are fair effort to get all the air out of these.

I've let the car rub without the expansion cap and it seems to let a lot of air out but still didn't fix it. Water pump is definitely working, same as thermostat. Hoping it is just airlock though

[Bamish1000]

Try massaging/squeezing all the hoses , covered with a rag so you don't get burnt

[Schalke04]

Try massaging/squeezing all the hoses , covered with a rag so you don't get burnt

I've tried that, still seems to have a problem... Anyone have any other suggestions?

[sports racer]

Run the car for a couple of minutes until the gauge shows it's warming up.

Put your hand on the radiator, is it warm? If it is then the water is flowing through your cooling system and the gauge is faulty or the thermostat isn't opening all the way. If it's cold then you have either a blockage or dud pump or faulty thermostat.

Cheers

Paul

[Schalke04]

Run the car for a couple of minutes until the gauge shows it's warming up.

Put your hand on the radiator, is it warm? If it is then the water is flowing through your cooling system and the gauge is faulty or the thermostat isn't opening all the way. If it's cold then you have either a blockage or dud pump or faulty thermostat.

Cheers

Paul

I ran a hose through the rad to make sure it wasn't blocked. I took the thermostat out put it in boiling water to make sure it was opening, opened fine. While that was off I ran the car and looked from an angle at the water pump which was spinning perfectly, while the car was off I also attempted to spin the impeller with no movement what so ever. The fan for the radiator does come on, but temp on dash doesn't get over half way. I'm really hoping it's not head gasket. I've squeezed all hoses and ran a hose through all hoses to try get rid of any blockages

[RedMk2Gti]

Have you tried to wire up a external temp gauge to check ? as sports_racer said it could be the gauge is faulty. Head gasket failure won't cause overheat, overheat will cause head gasket failure.

[aprr32]

Is the rad fan coming on,that will tell you if the radiator is flowing from the thermostat?

[sports racer]

temp on dash doesn't get over half way

So how do you know it's overheating?

[Jarred]

So how do you know it's overheating?

I'm with Paul on this one. Why do you think it's overheating?

[Schalke04]

I'm with Paul on this one. Why do you think it's overheating?

It's overheating because I can hear it boiling the water & it's coming out of he expansion tank cap. I've replaced the cap and it still does it.

[Jarred]

do you have a o ring on the expansion bottle? iirc some are meant to have them, some aren't.

The bottles are designed to have a natural overflow in them, and when you overfill them, the level automatically sorts itself out. is it possible that's all that's happening? What happens after the water has gotten out, and then the car is left to cool (ie, overnight). Do you come back to find that the level is ok? or is it low? Does the expansion bottle have a level indicator on it, factory and good OEM ones will, but some won't, and it's easy to overfill them.

[Schalke04]

do you have a o ring on the expansion bottle? iirc some are meant to have them, some aren't.

The bottles are designed to have a natural overflow in them, and when you overfill them, the level automatically sorts itself out. is it possible that's all that's happening? What happens after the water has gotten out, and then the car is left to cool (ie, overnight). Do you come back to find that the level is ok? or is it low? Does the expansion bottle have a level indicator on it, factory and good OEM ones will, but some won't, and it's easy to overfill them.

No o ring on the expansion bottle. If I open the expansion bottle when the car is warmed up it's got boiling water in the expansion bottle. Coolant level seems to drop when I leave it but I can't find a leak anywhere. It's doing the same thing my 1.8t did with a failed water pump except this water pump was clearly spinning and has no sogns of wear, the other spun freely. It's not just leaking out a bit it's basically emptying all the water once the cars warm.

[golfmeup]

Does sound odd.
What condition is your radiator?