The old radiator in my gti6 was knackered so I bought a nice shiny new one for it.

However, ever since fitting the new radiator I have had problems with losing coolant. I noticed this one day as I was just about to hit the motorway and the temp gauge was almost red and I stopped, cooled down and filled up with water.

It was then fine from Bristol-Manchester-London but on the M4 coming back to Bristol I noticed the temp gauge moving up in pulses if that makes sense. I then stopped again to fill up with water (there was very little in there). I then carried on again but after only a few junctions it went nearly red again. So again I stopped to fill up, but this time when I took off the cap the water shot out, so I must have overfilled it at the last stop.

I finally got home and started to check things over. The front of the block was slightly wet, so I have taken off the front slam panel and bumper so I can get really good access. I then ran the car until hot (disconnected fans and covered radiator) but I could not see any leaks. Apart from a tiny dribble from the filler cap which stopped really quickly.

I don't think it is the head gasket, as it is not down on power, not smoking, no oil in water or water in oil. However I have ordered a compression test kit just to be safe.

The only thing I did notice after turning it off from hot was a slight gurgling/hissing which sounded like it was coming from the middle of the inlet manifold. But this is where the fuel rail is, so maybe it was that??

Could it be the radiator cap? I have ordered a new one. Could it be that the slow speed fan has seized (which I found after removing the slam panel? If I am doing a compression test, how do I stop the engine starting?

Sorry for yet another losing water/ overheating thread, but I want to see what you guys think.

Cheers
H

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306 GTI-6 Now sold

Nothing in my passenger footwell.

Bit of an update. Did a hot compression test today, and got the following result:
225-230-220-210
So it looks to be okay? I have ordered a new radiator cap so I will see what that does.

Latest problem is that the electrics are now going a bit crazy - the green headlight light keeps flashing on and off, sometimes even when the keys are not in it, and after running when I turn it off by the key it runs on for a good 5 seconds. Also the right hand fan (left as you look at the car from the front) is now constantly running full speed.

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306 GTI-6 Now sold

That black cylinder is your heater fan the pipe is a drain incase water gets in there mine has snapped off too not a big issue. Did you bleed the coolant? Try a coolant presure test that will find the leak

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PS 3 tag stumpy555