dseag2

So, I've had my A4 since it was new and it currently has around 33k miles. Several years ago I had the thermostat housing replaced as is per usual on the A4. Then it failed a year later and was replaced again at no charge. My Coolant light started coming on sometime later but it would go off after I shut the car down and restarted it. The shop said it was a valve that needed to be replaced so they did that and no more issues. A few days ago my Coolant light started coming on again and never went off. I lifted the hood today and the reservoir was almost dry. I filled it but there is surely a leak again so it will be back in the shop on Friday. I love everything about this car and plan to keep it many more years but I'm distressed that this keeps happening again and again.

FYI, I use a European auto shop that is very highly rated online. I hate the Audi dealer and this shop seems to know my car. They once diagnosed a loose hose to the turbo due to noises and lag I was experiencing even before they took it into the bay. So, I don't think it's them but then again I don't see others in the forum having these recurring issues.

I did hit a rough stretch of road several months ago that literally bent my rim. Maybe that caused a leak in the coolant system as well? I guess I'll soon find out.

a2oc

amazon, buy a pressure tester and see where the leak is.

minmet

I am sure your Indy shop has the expertise. Just in case, have they looked into this coolant reservoir tank breather tube 8W0-121-081-AN as described by Digs in this thread: https://www.audiworld.com/forums/a4-...ation-3051737/

dseag2

Update. My shop did the pressure test and could find no leaks, even though the reservoir was almost empty when I refilled it. They could see the coolant that leaked into other parts under the hood and cleaned it out. They think it might be from the cap but are replacing that and the reservoir on Monday. They said I am good to go for the weekend and will take an hour on Monday.

This car has been trouble-free and really enjoyable aside from the coolant issues. I guess I will just carry around a jug of coolant in the trunk as long as I own it!