if it keeps doing it then the waterpump is most likely on its way out but not enough to have a visible leak
I have been observing the expansion tank coolant level and it was down to the lower level.
I thought that it might just be expansion and drove from Brisbane to Mt Tamborine then Oxenford back to Brisbane.
The low coolant alert came on and I topped up the expansion tank with 225ml.
There has been no evidence of telltale leaks on the garage floor nor the engine bay. I got my sniffer hound to smell for sweet coolant but nothing to detect there.
So where does 225ml of coolant vanish to?
Should I suspect a thermostat water pump failure? Or the elbow at the back of the engine?
I have warranty with VW, should I report this to VW with photos.
Cheers Al
if it keeps doing it then the waterpump is most likely on its way out but not enough to have a visible leak
Very very common issue on these engines. The waterpump/thermostat unit is made of plastic and either the unit itself develops a crack somewhere or the seal will leak.
The coolant will be no doubt dribbling down the front of the engine and onto the sump. Most of it will evaporate due to the engines heat but you will be able to find evidence of pink powder residue underneath the waterpump.
A new waterpump will set you back between about $1000-1500 depending on whether you use an aftermarket unit or a genuine unit (genuine costs more obviously) and labour cost.
I had mine replaced earlier this year and it was $1000 including labour using an aftermarket Geba branded unit. These units currently sell for $530 Geba Water Pump 11235/1 - Made in Germany | Run Auto Parts
Genuine units have recently had a price increase and are now around $900 (they were previously around $700) Water Pump & Thermostat Housing - Audi 8V & Volkswagen MK7 -EA888.3 — VAGPARTS Australia
you must have missed the key point that he has warranty from vw ... so after your little personal story.. he will pay $0
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I have no idea where the coolant goes on some engines. My son's Polo GTi (6c) had the pump and thermostat housing replaced under goodwill by VW and the selling (VW) dealer. Since then, there are no visible signs of leakage, the (awesome) VW specialist we see for that car cannot find any evidence of leakage, and somehow every 5 to 7 thousand kays, the reservoir takes up to a couple hundred ml's of top-up. It's like it disappears into an alternate universe.
My T-Roc (140TSI) had a drink of coolant about 6 months ago. No idea where it went. The level was perfectly stable before that, and it's been that way ever since.
My wife's car (Audi A4, 45TFSI) also seems to take a sip of coolant - about once every 15k km it needs maybe 100ml of top-up. Just enough that you notice, not enough to be a real issue.
Previous vehicles we've owned with the EA888 motor have not lost a drop of coolant.
I would bring it to the attention of VW if you are worried about it. The alternative is to track it for a while - see how long it takes for X amount of coolant to be consumed. Go from there.
I would be surprised if VW replaced the pump or thermostat housing without there being obvious signs of leakage - eg, a salty residue, or that coolant-coloured powdery residue that Lucas mentioned. Sometimes you need to look REALLY closely to see it - need the car up on a hoist, lower covers removed, and LOTS of light.
Cheers
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