Coolant intervals

[Stevesas12]

Hi guys, as a new 1M owner here in UK, just trying to trace service history with BMW. Have only a few service sheets with standard oil service & diff service last time around just this year.
Car is only on 24k miles, but being 9yrs old I have no record of coolant change.
Upon research BMW do fill for life regarding coolant since 2004 I have read.
Other cars I've owned, I've not let go more than 5yrs without a coolant change.

What is your opinions on this please. Car is stock power.

Thanks

Steve

[nachob]

Absolutely, you should change the coolant. Dealer will say every 2 years after the first change, I think 4 years is good, 5is the absolute the max I would ever go on coolant. It begins to break down and can attack some of the internal metals. Change it out. I normally do most maintenance myself but it's a mess and you have to know the procedure to prime the pump and you have to work your way around the intercooler so I take it in to dealer for this. It costs about $200 here in the US. If you do it yourself, make sure you get BMW coolant also, it's blue in color.

[CarJunkie]

I changed mine when I replaced the water last winter for preventative maintenance. It's a track car, so I could not risk a pump failure and they do tend to go out around 60,000 miles.

When you remove the main feed hose to the water pump, about 2/3 of the coolant will drain from the system. I did this about 6 times, replacing with distilled water then priming the pump each time, until I had essentially pure water in the system. After replacing the water pump, I put in 1 gallon of BMW coolant, 1 bottle of redline water wetter, and only as much water as was needed to complete the fill. That gave me an approximately 40% coolant/60% water ratio which is the minimum coolant ratio recommended by BMW, and provides slightly better thermal capacity for my track car which is never driven in winter.

The reason I did it this way was because it would be a royal pain in the ass to drain directly from the radiator with the intercooler in place, and I did not feel like taking everything apart which would've taken longer than simply draining, filling and priming six times.

The fluid that came out was 4 years old and looked muddy brown. Definitely needed to be changed.

[nachob]

Originally Posted by CarJunkie

I changed mine when I replaced the water last winter for preventative maintenance. It's a track car, so I could not risk a pump failure and they do tend to go out around 60,000 miles.

When you remove the main feed hose to the water pump, about 2/3 of the coolant will drain from the system. I did this about 6 times, replacing with distilled water then priming the pump each time, until I had essentially pure water in the system. After replacing the water pump, I put in 1 gallon of BMW coolant, 1 bottle of redline water wetter, and only as much water as was needed to complete the fill. That gave me an approximately 40% coolant/60% water ratio which is the minimum coolant ratio recommended by BMW, and provides slightly better thermal capacity for my track car which is never driven in winter.

The reason I did it this way was because it would be a royal pain in the ass to drain directly from the radiator with the intercooler in place, and I did not feel like taking everything apart which would've taken longer than simply draining, filling and priming six times.

The fluid that came out was 4 years old and looked muddy brown. Definitely needed to be changed.

What you mentioned is one of the reasons the dealers say 2 years because they don't pull all of it out. They drain 2/3 - 3/4 out and re fill with fresh stuff. So if you do it every 2-3 years you are still refreshing it over time. your method is optimal but in the case of the original poster, anything would be bonus now. Even a regular drain and fill would stabilize the coolant. Also for some time I wasn't sure whether Deionized water or distilled were best for diluting. Both or OK but the Bentley manual says to use distilled water as well so that is what I do also.

OP are you thinking of doing it yourself or having shop do it? If you DIY, maybe Carjunkie can share the pump priming steps and expansion tank purge screw process.

[CarJunkie]

The purge screw should be open when pouring fluid into the reservoir, to allow air a route out of the system. It should be closed before priming. I believe the priming cycle is started by turning ignition on without starting the engine, setting the heater to max heat, and pressing the accelerator pedal to the floor for 10 seconds. You will hear the pump make noise for about 8 minutes. Battery tender is a good idea. It is very easy!

Here is a link to a great DIY vid from Bavarian Auto for the pump and thermostat replacement that I used. It's detailed and long, but getting to the pump and popping off the first coolant hose is all you would need to do to drain 2/3 of the fluid. As stated above, I reattached the hose, filled, primed and dumped again about 6 times, and would do it that way again to avoid all the disassembly needed to get to the radiator drain.

[ayao]

ECS sells a Schwaben coolant purge / flush contraption that worked perfectly when I did mine a while back; it made the overall process much less messy than many of the DIYs I had seen.