Mk7 TDI Coolant leak...

[SniperMonkey]

Hi all,

For the past month or so, randomly, the tank will empty its entire coolant on to the floor so when I get in I get the big red warning. I keep spare coolant in the boot because of this and fill up when needed. It happens mainly when parked on a slight gradient (up or down doesn't matter). Tired of it I took it to a friend of mine that runs a reputable garage for him to work on it. So far he's jacked it up at the back, it hasn't leaked. Jacked it up at the front, it hasn't leaked. Put dye in to find a snail trail...no leak. Pressure tested it, no leak.

He's unable to make it leak but I know when I collect it, it's gonna do it eventually. Could be an hour, could be a couple of days.

Anyone got any advice on what to do, where to look or any way to make it leak? Is it less likely to leak when its cold and needs the engine running for a bit?

Any advice would be greatly appreciated as it's driving me wild and costing me a chunk in coolant.

Thanks

 

[jimlloyd40]

The place it leaks most often is the thermostat housing but it's a very slow leak and will pass a pressure test because it only leaks when driving. Usually found by the staining on the housing. But I've not seen anyone with a puddle from it. Check for stains on the housing.

 

[SniperMonkey]

The place it leaks most often is the thermostat housing but it's a very slow leak and will pass a pressure test because it only leaks when driving. Usually found by the staining on the housing. But I've not seen anyone with a puddle from it. Check for stains on the housing.

This seems to be different. I stopped off at a garage for a coffee on Saturday after a bit of a drive out and in the time it took to get a coffee and walk back (3-4 mins) it had emptied the entire contents on to the ground. It was a full reservoir, there was a lot of coolant on the ground. People even told me as I was walking back I had leaked coolant.

 

[jimlloyd40]

I wonder if it's blocked somewhere and getting too hot and pushing it out of the reservoir overflow? Where is it on the ground under your car?

 

[SniperMonkey]

I wonder if it's blocked somewhere and getting too hot and pushing it out of the reservoir overflow? Where is it on the ground under your car?

It's alway front right which would suggest under the reservoir but he can't see anything. Like I say he put dye in and tried everything to make it leak and it never did. I thought it always did it after a run but I do 20 miles to work and 20 back each day and it can be days before it leaks. Its very confusing.

 

[jimlloyd40]

Do you see staining under the reservoir anywhere?

 

[SniperMonkey]

Do you see staining under the reservoir anywhere?

I'll ask him tomorrow as he's gone home for the day now but he said he sees no evidence of a leak anywhere, which is the bit thats confusing me.