J666

Hi everyone,

Since it’s gotten colder out, I got the low coolant warning message. Went to MB and they gave me a bottle of blue coolant. When I opened my reservoir, the coolant was green. Have owned this car since new and never serviced the coolant.

Does the blue coolant turn green over time? That’s what the parts guy said.

Is it safe to pour in? Really ticked off as I made a 2 hour trip to the dealer.

bmwpowere36m3

Assuming your story is correct about owning since new, I’d say yes. That said, I haven’t seen original MB or BMW blue coolant turn green (like generic fluorescent green stuff).

It starts a very dark blue and over time becomes bluish green.

pierrejoliat

The last Benz I had with green coolant was a '93 since 2001 all my Benzes had blue coolant Pentafrost AF.

MBENZTECH

With time it looks like a green color but it no worries..... just add the blue.

Arrie

I don't think any color coolant from MB will hurt your engine. I really don't think any coolant today from any car parts store will hurt your engine. All engines today are built pretty much withy the same materials but splitting hair even I go to MB to get the coolant for my cars.

If I was the OP I would be more worried about why I'm getting the low coolant warning, i.e. where is my coolant going to?

bmwpowere36m3

I agree, if you were doing a full flush... many coolants would work fine for their specified service life (some longer than others).

However for top-offs, mixing chemistries is not advised as it can have adverse affects and/or lower service life. Now in an emergency, your low on coolant, on a road trip, at a gas station... sure, any coolant is better than none.

I also agree with your last point, about leaks... but some minor coolant loss over many years isn’t abnormal. Checking none the less is a good idea.