[Terrier15]

Well, not the first time the service department has misrepresented a situation.

[Inprogress]

I had the low coolant light come in yesterday, it was the 2nd time in 6 months, but this time they found out that the expansion tank was leaking so they will be replacing it. I wonder if the replacement part is any better than what was originally on the car. My car is a 2020 with 35k on the odo

[AHall]

Originally Posted by Inprogress

I had the low coolant light come in yesterday, it was the 2nd time in 6 months, but this time they found out that the expansion tank was leaking so they will be replacing it. I wonder if the replacement part is any better than what was originally on the car. My car is a 2020 with 35k on the odo

Some have reported leaks after the replacement tank was installed. Was it replaced under warranty?

[SeatownF80]

I had the warning back in november. I kinda ignored it because it goes away after a while or if you restart your car again. When I finally checked it was pretty low. Like you cant even see the fluid with a flash light low. I topped it off and checked for leak with a blacklight and found nothing. Its been fine since. Coolant stayed at max level.

[Inprogress]

Originally Posted by AHall

Some have reported leaks after the replacement tank was installed. Was it replaced under warranty?

Oh damn, I asked my SA and he mentioned the replacement being better. And yeah, it was replaced under warranty

[DEW67]

I just had my coolant topped up for the second time in probably 6-8 months. This most recent time, my SA said the tech's supervisor looked for a leak and couldn't find one. How does the coolant level go down if there isn't a leak somewhere? Is that even possible?

[GTTC]

Originally Posted by DEW67

I just had my coolant topped up for the second time in probably 6-8 months. This most recent time, my SA said the tech's supervisor looked for a leak and couldn't find one. How does the coolant level go down if there isn't a leak somewhere? Is that even possible?

Mine did go down a bit 24k miles then at 25k it failed. Lucky for me I saw it early enough to get it replaced plus all injectors on the side (coolant got to them) under warranty. I bought the Level catch can and be installing it this weekend.
To be honest on other cars coolant does go down a bit due to evaporation from the expansion/vacuum cycle. So not far fetched. Just have to watch it.

[pmsteinm]

Originally Posted by DEW67

I just had my coolant topped up for the second time in probably 6-8 months. This most recent time, my SA said the tech's supervisor looked for a leak and couldn't find one. How does the coolant level go down if there isn't a leak somewhere? Is that even possible?

You are right that there must be a leak. The problem is it can be so slight that the pressure test isn't long enough to detect it. I have found the coolant level changes a lot with temperature so make sure when you check it is at the same outside temperature with the car completely cooled off. But if the level drops over time at same temperature there is a leak. Could be cap, tank, hoses, head gaskets, etc. I am pretty sure I had a cap leak and after they overfilled during a leak test and it all leaked out it seemed to fix my cap issue. Maybe it lubricated the gaskets or something. Either way i check for white spots every time I was the car.

Oh in fairness to the dealer, ISTA says to overfill the tank when filling. Not sure how that squares with "don't get coolant on the injectors". Sigh. German engineering.

[smbsocal]

My M5 had the warning once after a year and I topped it off and haven't had an issue since, 2 years out after that.

[pmsteinm]

Originally Posted by smbsocal

My M5 had the warning once after a year and I topped it off and haven't had an issue since, 2 years out after that.

I think is a common thing since the coolant level varies so much with temperature. Depending on the factory fill and your local lowest temperature you might get a warning or two until you get the minimum level dialed in. I would only say you have a leak if you keep needing to add.

I had my level drop twice on temperature changes but I felt I had a leak too because there were white spots on the tank sides.