After changing the oil in my 195,000 mile 335, I figured I'd make use of the two gallons of BMW coolant I had sitting around. Rather than get the car in the air, take off the splash shield, take out the intercooler, drain the radiator, and then think about draining the block, I took a short cut. I just disconnected the return hose that goes back into the reserve bottle. While aiming that hose into a container, I just kept filling the tank as the warm engine idled. Swapped about a gallon and a half in about two minutes. The good news is it was fast and east, and I didn't have to bleed it (which requires a protocol to run the electric water pump). Bad news is I diluted the old coolant instead of really changing it.
The old coolant was in there for 3 years, when I changed the radiator. That job brought me to tears. It looked weirdly dark compared to the new coolant, but otherwise good.
Thought I'd share.
The old coolant was in there for 3 years, when I changed the radiator. That job brought me to tears. It looked weirdly dark compared to the new coolant, but otherwise good.
Thought I'd share.
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