Holson

Hey All

Happy Christmas Eve!

Ever since I moved to a house with a garage instead of a large shared garage I started noticing a coolant like smell after running the engine a while - doesn’t even have to be that long of a drive. It’s got 6000 miles on it and never had the coolant topped off as far as I know during

ive monitored both the tiny and the big coolant looking tanks and they both have stayed at the same level.

anyone else experience the same - would rather not involve my dealer on a hunt for something normal







thanks all - happy holidays and stay safe

chassis

Do you smell the coolant inside or outside the vehicle? Do you smell the coolant at one location in or around the vehicle? Where?

Holson

outside of the car. I can’t really tell where it’s from but it fills the garage with it will try to pinpoint next time

streborx

The coolant overflow tank allows a radiator to be topped off and it catches heated coolant whose volume expands and needs someplace to go. When the engine cools, the coolant in the tank gets drawn back into the radiator. If you're smelling coolant while the engine is warming up and when coolant is flowing into the overflow tank, the smell could be just the air that's being vented from the tank by the coolant displacing it. As long as your coolant level remains full, there shouldn't be any problem. Check the smell intensity around the overflow tank.

chassis

And the smell could be coming from "sweating" or "vapors". My service manager uses these words often to describe what are obvious leaks to anyone besides him. Check in the fender behind the headlamp for the coolant circulation pump. There are several small-medium diameter hoses between the circulation pump, reservoir and radiator. The multitude of hose connections in this area can be prone to very slight leaks that are detectable by smell. My W166 M276 does this. The hose clamps connection all of this rat's nest of hoses are coated with a "sweat" of dried coolant. I don't have a wet leak or drip, just perspiration.

I expect at high milages these hoses and circulation pump will need to be replaced. If you search this site, the circulation pump appears to be a weak link across multiple models.

Holson

Thank you @streborx and @chassis ! I’ll leave this be for now since the overflow tank’s level is allways the same. I will casually mention it if it gets worse or if I start to see coolant sweats on hoses at the next service.

prodigymb

did you ever figure out where the coolant smell was coming?

alx

they all stink... ignore unless you are loosing coolant