Oh crap! I didn't use BMW OEM antifreeze!
 

I didn't realize that BMW recommends nitrate/phosphate-free coolant. Last night, I was just checking out my 2010 X5 for a road trip this weekend (checked the tires, water, etc.) and saw that the coolant level was low. I had a jug of coolant in the garage and just filled it up with 50/50 coolant and water (filtered via reverse osmosis). I didn't put much coolant in though because the reservoir wasn't very low.

It's not a big deal, right? Or, am I just being paranoid because it wasn't one of the listed non-OEM coolants allowed by BMW, but one I bought from Autozone a few years ago.

It can, in fact, be quite a big deal.

Was it the "Mixes With Anything" type, or just regular old anti-freeze.

The "mixes with anything" stuff is made up of:
http://www.mightyautoparts.com/pdf/msds/vs7/af-888.pdf

Ethylene Glycol
Diethylene Glycol
2-Ethyl Hexanoic Acid, Sodium Salt (Corrosion inhibitor)
Neodecanoic Acid, Sodium Salt (Corrosion inhibitor)

It is both Nitrate Free & Phosphate Free, and claims to be OK with ANY other coolant chemistry.

Other coolants use additive packages that may not be compatible with the BMW OEM coolant.

Having read up on this when I was a VW owner, I know that there are certain combinations of VW OEM coolant (G12, G12+) with other coolants that could have catastrophic consequences.

Saturn recalled cars that had been built with the wrong antifreeze and the owners were given brand new cars.

Chuck

It was just regular basic antifreeze. I just put in a tiny amount....maybe half a cup or a quarter cup. The coolant reservoir was on the low indicator and I filled it up half way. Then, I put filtered water up to the Max line. It should be okay, right?

should be ok... one day i was super tired had a brain fart and instead of filling the windshield fluid in the right spot i dumped a little in the coolant container.

that was 38,000 kms ago. but to put your mind at ease just go get a coolant flush but just dont tell them why. just say oh i treat my car like no other.

Yeah, I hope it's okay. Considering that it's a $60k car, I would hope that 4-8 ounces of the wrong coolant isn't going to cause serious damage. That would be kind of sad!

The trouble with having the wrong antifreeze in an aluminum engine is that it can cause corrosion. I would drain and refill the system right away.

Chuck

If you have not run the car, simply drain the coolant reservoir...otherwise drain the whole system.

I know you are trying to find people to agree with you and provide assurance, but unless we know the coolant you added is compatible, there is a chance that the chemistries will lead to issues.

i think the coolant capacity is about 12 Liters (3+ gal), so i dont think 8 oz of another coolant is actually going to do anything harmful.

I think you want to do some reading on coolant chemistry and what cause precipitates and corrosion... it is not a volumetric phenomena, but rather very small amounts of impurities (ie ~1%) can cause issues. An incompatible fluid MIGHT act as an impurity.

I'm not saying this mixing of an unknown coolant into the BMW fill is an issue, but I am saying that dismissing this by thinking "It wasn't very much" is wrong.