BMW seem to think there is no need to change the coolant on our cars, despite the manufacturer Glysantin recommending it is done every 3 to 4 years because of its properties breaking down and becoming acidic.
Water pump failures are common on E series cars including on the N55 engine so I consider a coolant change good insurance.
I completed the change on my M Lite today. I didn't manage to get all the coolant out unfortunately though, I drained 4.5ltr by pulling the main hose off the water pump, system capacity is 6.7ltr. So not perfect but a damn site better than BMW's lifetime fill idea. Here's how to do it.
Preparation:
Required;
5ltr distilled water
3ltr BMW coolant - don't mix coolants so stick with OEM. Part number for 1.5ltrs is 83512355290.
8mm socket for engine cover bolts
Flat blade screw driver for jubilee clips
Safety glasses to prevent coolant getting in your eyes
Make sure your engine is cold before attempting this.
First, the process involves bleeding the system by running the water pump off the battery for 12 minutes, so make sure you're battery is charged before starting. Or hook up a trickle charger that is safe to use with the ignition on.
1. Safely raise the car for access under the engine.
I did this with the car on ramps in my garage. Access was tight but doable.
2. Remove the floor panel under the engine by removing the 8mm bolts, there's about 15 to remove.
3. Remove second plastic sump panel held on by 3 x 8mm bolts. You will now be able to see the water pump above the steering rack. It's on the LH side of engine. I'll upload a photo when I get chance.
4. Get a container ready to catch the coolant and put on your eye protection. Loosen the jubilee clip on the main hose which points rearwards. Coolant will trickle.
5. Pull the hose straight off, it's not threaded, just wiggle it off. Mine came off fairly easily. Coolant will gush out.
6. Open the coolant reservoir fill cap to let the coolant drain quicker.
7. To get the most coolant out the second hose attached to the water pump should also be removed but I couldn't get this one to budge so left it for fear of damaging it or not being able to get it back on. It's harder to access than the main hose too.
8. When the coolant has stopped draining, refit the hose and jubilee clip.
9. Open the bleed screw on the reservoir, located next to the fill cap. Fill the system with 50:50 mix of BMW coolant and distilled water up to the max line.
10. Next is the bleed procedure. Replace bleed screw and fill cap. Start the ignition without starting the engine. Turn on the headlights. Set the heater to max temp and fan to lowest setting. Hold accelerator down for 10s or until water pump starts.
11. The car will run an automated bleed cycle which lasts about 12 minutes. You will hear the pump running and coolant flowing as well as air moving.
12. When complete, top up coolant to max line. Mine needed another 300ml.
13. Check battery level, charge if required and rerun bleed cycle. This isn't fully necessary but I did it as a precaution to make sure all trapped air was removed.
14. Start engine and idle for a couple of minutes. Check for leaks.
15. Refit the engine covers. You have now given your cooling system a clean bill of health!
The whole thing took me an hour taking my time. If you're keeping your car as a long termer it's an hour well spent in my opinion.
Water pump failures are common on E series cars including on the N55 engine so I consider a coolant change good insurance.
I completed the change on my M Lite today. I didn't manage to get all the coolant out unfortunately though, I drained 4.5ltr by pulling the main hose off the water pump, system capacity is 6.7ltr. So not perfect but a damn site better than BMW's lifetime fill idea. Here's how to do it.
Preparation:
Required;
5ltr distilled water
3ltr BMW coolant - don't mix coolants so stick with OEM. Part number for 1.5ltrs is 83512355290.
8mm socket for engine cover bolts
Flat blade screw driver for jubilee clips
Safety glasses to prevent coolant getting in your eyes
Make sure your engine is cold before attempting this.
First, the process involves bleeding the system by running the water pump off the battery for 12 minutes, so make sure you're battery is charged before starting. Or hook up a trickle charger that is safe to use with the ignition on.
1. Safely raise the car for access under the engine.
I did this with the car on ramps in my garage. Access was tight but doable.
2. Remove the floor panel under the engine by removing the 8mm bolts, there's about 15 to remove.
3. Remove second plastic sump panel held on by 3 x 8mm bolts. You will now be able to see the water pump above the steering rack. It's on the LH side of engine. I'll upload a photo when I get chance.
4. Get a container ready to catch the coolant and put on your eye protection. Loosen the jubilee clip on the main hose which points rearwards. Coolant will trickle.
5. Pull the hose straight off, it's not threaded, just wiggle it off. Mine came off fairly easily. Coolant will gush out.
6. Open the coolant reservoir fill cap to let the coolant drain quicker.
7. To get the most coolant out the second hose attached to the water pump should also be removed but I couldn't get this one to budge so left it for fear of damaging it or not being able to get it back on. It's harder to access than the main hose too.
8. When the coolant has stopped draining, refit the hose and jubilee clip.
9. Open the bleed screw on the reservoir, located next to the fill cap. Fill the system with 50:50 mix of BMW coolant and distilled water up to the max line.
10. Next is the bleed procedure. Replace bleed screw and fill cap. Start the ignition without starting the engine. Turn on the headlights. Set the heater to max temp and fan to lowest setting. Hold accelerator down for 10s or until water pump starts.
11. The car will run an automated bleed cycle which lasts about 12 minutes. You will hear the pump running and coolant flowing as well as air moving.
12. When complete, top up coolant to max line. Mine needed another 300ml.
13. Check battery level, charge if required and rerun bleed cycle. This isn't fully necessary but I did it as a precaution to make sure all trapped air was removed.
14. Start engine and idle for a couple of minutes. Check for leaks.
15. Refit the engine covers. You have now given your cooling system a clean bill of health!
The whole thing took me an hour taking my time. If you're keeping your car as a long termer it's an hour well spent in my opinion.