Coolant leak - Polo GTi 6r 1.8 tsi

[purch123]

Hi guys,

Ive had an ongoing coolant leak whereby I need to top up with vw recommended coolant around every 2-4 weeks (approx 100ml up to max).

My friends cupra with the same engine was using much more than me and ended up needing a load of work done to car. He has since got shot of the car as after numerous issues it was never the same.

My car had a slow impact crash where I rear end shunted a vehicle at a roundabout around 2 months ago and, fortunately the damage was purely cosmetic (low speed impact but admittedly my fault) - the coolant issue I was well aware of before the crash and had been topping the expansion tank up frequently every 2-4 weeks or so, around 100ml to a cold engine up to the max line.

The car mechanic was thorough, knowledgable and advised to keep an eye on it and top it up where necessary. If it gets worse I can bring it in for him to look at.

Anywyay I bought some Holt gold coloured coolant sealant and placed some in the expansion tank in the hope it would seal a small air hole somewhere. Does anyone have any experience doing this? I think a 1000 miles of driving would give me a good indicator as to whether it's worked.... Or not. I'd be grateful for your input and alternatives/recommendations you'd be willing to share. The mechanic always said pop it back in if its gets worse. It didn't seem to be a major area of concern at present but may lead to something worse in time. I trust the mechanic, very old school, quite dry but clearly knows what he's talking about.

He was recommended by another mechanic I know extremely well who couldn't fit me in at the time.

Sorry for the long post but your help/advice would be highly appreciated.

Cheers

[john__m]

i had the exact same issue with mine, one dealership did numerous pressure tests but said the system was fine so
i took it to another and it turned out to be the radiator, they replaced it and it has'nt lost any coolant since.

[Dink]

Thermostat housing is common for leaking on these cars.

Not sure where it is but I'd be looking there first.

[Gee40]

I think Dink may be on the right track with the thermostat housing as a leak on mine was spotted during a service at a VW dealership and replaced just before the warranty ran out. From memory the housing is visible from underneath the car as they sent me a video of the car up on the ramp pointing to the leaking housing with a laser pen. When talking to the technician he did mention that the thermostat housing is just about the only common issue on the 1.8 6c GTI engine ( that and a few dodgy early turbochargers)

[purch123]

Thanks very much for the useful info guys, much appreciated

I'm going to keep on eye on it over the next couple of weeks to see if this Holt sealant does anything. My car is also due a service soon, so if it is still playing up at service time I'll mention it as something to be checked out.

Will keep you updated. Cheers.

[purch123]

Might be too early to say, but the Holt Radweld stuff seems to be doing its job... No further coolant leak since my last post (touch wood). I know it hasn't been any particular length of time since my last post but I've done quite a few miles and the level hasn't changed. Usually, by now, I would have had to top the coolant up. Will still mention it when the car goes in for its service. Cheers.