BMW "Lifetime" coolant...

[garz747]

I must have one of the lowest mileage Z4M coupes on the forum. Currently at 31000kms(19220mi). I use her as a weekend toy in cottage country. The coolant is still dark blue and has no particles floating in it. The prestone tester says its good to -40c. Do I need to worry about changing it out due to this car being 14 years old?

[Squidd99]

I'd weigh keeping an old solution that's been circulating in that radiator for 14 years against the cost of some new coolant.

[Clearancediver]

Definitely needs to be flushed….

[grannyknot]

BMW's blue coolant is pretty good stuff but 14 yrs of heat cycles has almost certainly worn out some of the additives, probably time to flush.

[Gamb1t]

Even if you are changing it now, I fear some corrosion may have already started. It's not like aging fine wine here.
The Prestone bulb tester only confirms freeze/boil points. The invisible killer is the coolant acidity and resulting corrosiveness. You can use pH strip to test it. Or another way is by using a multimeter for conductivity. There is a tolerable range that you can reference.

[Squidd99]

ALSO, don't be fooled by names and labels: my guess is that "lifetime coolant" only means it's good for the life of the coolant (which surely died years ago).
This free tip comes with a double-your-money-back guarantee.

[Sergio19]

S54 is a mixed metal engine (alum head, iron block) so corrosion is a big concern. Change every 5 years or less.

[rsutoratosu]

Originally Posted by Gamb1t

Even if you are changing it now, I fear some corrosion may have already started. It's not like aging fine wine here.
The Prestone bulb tester only confirms freeze/boil points. The invisible killer is the coolant acidity and resulting corrosiveness. You can use pH strip to test it. Or another way is by using a multimeter for conductivity. There is a tolerable range that you can reference.

Thats what I figured also, I remember they turning acidic..