Real quick, coolant light(yellow) came on Friday night when I put on the heater so I mistakenly picked up some prestone 50/50 and topped it off. I probably only put in less than half a cup. I then realized I should have picked up some BMW antifreeze. No problems so far and I’m going to have it flushed (50k appt ) on Friday money permitting when I do the brakes. Is the Prestone a problem even in that small of an amount? BTW it’s an 04 330 ZHP.

There shouldn't be a problem. Just flush it out when you can.

Its the same crap just 1/2 the price. You'll be fine.

My mechanic says Prestone is the best and that's all he uses. I'm not saying that's true, but he knows his stuff, is BMW trained, and has about 30 years of experience, so...

I like buying the Prestone 50/50 stuff. What I don't like is how they charge as much or more for the 50/50 than they do for the full-strength stuff. You get half the product! I guess they know people are willing to pay for the convenience. (I know, I know, ten people will chime in to claim they get Prestone 50/50 for $0.12 and then get a $20.00 rebate... All I know is what I see where I live. In Advance Auto Parts, they actually charged more for the 50/50. In Autozone, they charge $12 for 50/50 (I didn't compare to the full-strength stuff.)

You'll be fine. I personally stick to the BMW stuff, since it isn't that expensive. Flush it when you can, it's just good sense to stick to one fluid.

Its not like its going to blow up...and the prestone is "mix with anything" coolant

psh.. i use prestone