G40 turbo overheating

[denisga44]

Hi, I have some issues with the cooling system in my turbo G40. It is overheating all the time, even though the temperature gauge is showing max 70C. I have changed the thermostat, the water pump is OK, but the radiator and the bottom hose from the radiator is cold. It looks like there's still air trapped inside, but there is no air coming out in the expansion tank nor the bleeding screw. The heater is blowing hot air. Any ideas?

[dubstar]

blocked radiator.

[denisga44]

radiator is not blocked 

[Yoof]

Take a picture of your coolant hose routing.

[denisga44]

all the hoses are connected in the right way and everything was working fine. in winter I wasn't using the car at all and now it's boiling water

[Andy]

Boiling water as in pissing out the expansion tank cap? Check that the seal on that is okay - but sounds like you've got a blockage if neither the rad nor its pipework are getting warm.

[denisga44]

I've tried everything and there is water flowing around the temp sensors and still it doesn't show anything. However when I tried to heat it up with a lighter, the gauge started going up normally, so I don't think it's with the wiring or the  sensor itself.

[denisga44]

When I hold te upper hose which leads to the radiator and I rev the engine I can feel a change in pressure, it becomes slightly harder.  So my main problems are: 1. boiling water 2. cold radiator hose 3. temp gauge showing up to 70Chen

[Andy]

You checked your water pump is okay, all fins still attached? And where is the coolant boiling out from - the expansion tank?

[denisga44]

yes, it is boiling in the expansion tank, and it is blowing out through the ventillation hose (?) on the side. the inlet hose to the radiator is hard as well,
the water pump is ok it is not seized or anything.

[GR40]

Is your turbo watercooled? And if it is. Where have you taped into the system?

[denisga44]

yes, it is watercooled. inlet is before the rad and out is before the exp. tank. last season it was working ok.

[josé]

Could you not remove the thermostat as a test and see if you have circulation through the radiator?? I have not done this and don't know if it can be done but just a thought,

Before you re-fill the cooling system take off the 180 bend off the side of the engine and drain the complete system from there and the bottom rad hose, I didn't do that years ago and caused the car to overheat by air locking the system and bleed any air out of the heater matrix,

That's what I would try and see if you get no circulation through the rad then the stat could be faulty

Josh

[Andy]

Is this boiling up just idling?

Everything you're saying suggests there's a blockage, or no flow due to the pump not pushing the coolant around. Have you actually had the pump out to check the fins on it are still attached? How have you checked the radiator isn't blocked? Have you run it with the 'stat out? Did you check that the expansion tank cap is sealing properly?

Presume you've bled the system correctly with the heaters on full etc. already.

[denisga44]

what are the dimensions of the radiator I should use?