venomous99

timely post. our 2017 w/ 36k miles had the low coolant light turn on last week. turns out the coolant tank was low. i topped it off w/ some 50/50 g13 coolant and will be taking her in tomorrow. also didnt observe any leaks or anything.

RJC 1

Pressure testing alone wont catch it if it's a seeping type leak...my XKR Jag had this and it was from the water pump.

noxqzs

I had a similar issue and on mine it was a leak at the thermostat.

venomous99

audi found a small leak around the tstat. under warranty the tstat and water pump will be replaced since apparently these are one unit. reading the replies here, this is not an uncommon issue.

AlbertQ7

Thanks for all the responses. I have my appointment the second week of January. The level has been going down VERY SLOWLY since refilling, so I'll keep watch on it but shouldn't be an issue going a few more weeks. It's helpful to know the water pump/thermostat is the most likely culprit. That way if the dealer says the pressure test was negative, I can ask them to keep looking.
(I'll try to have them do the top view camera TSB at the same time.)

AlbertQ7

This is why I LOVE this forum! My Q7 is in for service for the coolant leak. The dealer sends "service video" where the tech is doing a walk-through of the car inspection on the video (kinda cool actually). Near the end he states that he did not find the leak and pressurized the system and it held for a certain number of minutes. He then said that sometimes the coolant level just needs to settle on new cars. I called the service advisor, but his phone went to voicemail. I left a detailed message saying that having the whole reservoir of coolant disappear and having the level go down a little again over the last 1000 miles is not "the coolant level settling". I mentioned the water pump and t-stat and the fact that the pressure test wouldn't necessarily reveal that. Hopefully they are looking into it further.... I'll call again in a bit. I appreciate the responses here so I know to keep pushing them...

Question: how accessible is the water pump/t-stat in order to visually inspect it?

RJC 1

He/she should be able to view the wp from below it once in the air and the t stat from above...plus there are other viewing tools/scopes they can easily use

AlbertQ7

RJC 1

Very odd the bottle was completely empty, has the vehicle been regularly serviced, and if so it should have been noted coolant was low added at one point? FWIW, my new at the time jag 2013 xkr had a nagging burnt coolant smell which at first they could not find and pressure testing proved futile, as was checking the wp etc...after several more visits/complaints they did replace the wp saying there was indeed a small seeping type leak and the issue was resolved. I did not have such the huge loss of coolant you are experiencing however

AlbertQ7

Yes, the car was serviced at that dealer for it's 10K service this past summer. I suspect the coolant was low at that point, but not noticed - perhaps the engine was warm when they looked, so the level appeared higher. The night I got the notification it was REALLY cold, and I have noticed quite a swing in the level based on temperature. I have done roughly 1,100 miles since filling it, and it has gone down but rather slowly. When I picked it up today, it was quite a bit over the "MAX" line, but the engine was warm. I'll be curious to see what the level is tomorrow morning with a cold engine. If it is over "MAX" when cold, I'm going to remove some fluid so it is easier to track and so that by the 20K service they don't say that the "level still looks good" just because it started overfull.