[fl335i]

Guys, the battery is in the trunk, bit hard to check coolant electrolysis the conventional way. BMW gives you a negative groud lug for juming right next to the coolant resv. So I used it instead of the neg post on the batt. Voltage was pretty high, over the .3V general rule of thumb. Can someone post how BMW specs to check this and what the limits are. Have others had issues with coolant electrolysis? My car only has 45k original miles. I top off the coolant with distilled water, since I've bought it with 35k I've only put a few ounces in it being it was a touch low when I got it. I'm really worried about the high voltage I'm getting on my E90.


Been searching around and looks like since 2004 BMW now calls coolant "lifetime". Right. My '08Lincoln MKZ calls for 100 or 120k coolant flush interval one of the two. My MKZ is showing pretty high electrolysis also, but still under the .3V safe limit. Showing .25V. So I'm thinking the coolant will need to be done around 80-90K Vs the 100-120k the book calls for on that car.

Checked my wife's '08 C300 with 40k. Lowest voltage of our 3 cars. Hers is at .19V.

[NiVeDh]

Might as well replace the coolant now. It's cheap and easy to do. Worth it for the peace of mind.

[fl335i]

^yup. Wondering if BMW sells it "pre-mixed" and ready to use. If available, I'd prefer to go that route even though it's more expensive.

[NiVeDh]

Originally Posted by fl335i

^yup. Wondering if BMW sells it "pre-mixed" and ready to use. If available, I'd prefer to go that route even though it's more expensive.

Personally, I buy the 1 gallon BMW jug (around $20) and mix it to whatever ratio desired with distilled water ($0.88/gal at Walmart).

[fl335i]

I don't even think BMW sells pre-dilluted coolant. We will see tomorrow when I call the parts dept. I checked the voltage again today, it's not terrible... .24V. But I think I'm coming to grips with the fact even these long life coolants are maxing out at 5yrs/100k which ever comes FIRST. If you want to keep your car long term.