Quote:
Originally Posted by David_Vasha
After countless research on the topic with not much to show, I decided to pull the trigger and get this DIY done. I've got to say, after doing it through this method I can finally say that I got 100% of my old antifreeze out of the system. The reason I can confirm this is because whoever had the car before me put green coolant! Which we all know is a big no no.
USEFUL INFO: The N55 model engine uses 10 liters of coolant.
Furthermore, the tools you will need;
- [ ] Common sense (very vital here)
- [ ] A hose that is long enough to reach the vent hose all the way to your designated bucket
- [ ] 6 or 7 gallons of distilled water
- [ ] 2 gallons of OEM BMW non-diluted antifreeze
- [ ] A bucket(s)
- [ ] A couple of rags or towels
Essentially how the cooling system works is that it is circulated (obviously). The vent hose that connects to the reservoir is basically the return line in this case. The coolant passes through the entire system and returns to the reservoir through this single hose.
1. Release the vent hose from the coolant reservoir by prying the metal clip up with a small flathead. Then remove the hose by gently pressing it off the nipple of the reservoir.
2. Now get your hose, preferably a clear one to monitor the fluid coming out, and find a way to get the vent hose and the hose you're using to connect securely so that coolant doesn't leak out. The best way to do this is to have a hose with a wider diameter than the vent hose. Mine wasn't larger in diameter so I used tape and wrapped it in a microfiber towel to control any leaks. This worked well too.
3. With the cap off the reservoir, get in the car and turn the heat to max with the lowest fan speed. Also turn off The AUTO, AC, and other functions.
4. Start the car.
5. While the car is running you want to make sure the reservoir doesn't run empty and keep it filled with distilled water at all times
6. Monitor the fluid coming out of the hose. You will know that all of the old coolant is gone when the fluid in the hose runs clear.
7. With the car still on and running fill the car with the BMW coolant. You don't need to dilute it because the system is full of distilled water, this mixing with it in the system. My logic was that since the car uses 10 liters of coolant, and I filled the car with distilled water entirely, it's safe to say I would need to put in 5 liters of BMW coolant. If you feel that this method is faulty, just monitor the fluid that comes and make sure the mix is how you like it.
8. By the end of this, you should see the blue BMW coolant mix coming out. At this point you can shut the car off and insert the vent hose back into the reservoir tank.
9. This step isn't necessary in my opinion, but just to make sure there are no air pockets in the system, I run the BMW coolant bleed procedure which is basically having the car in accessory mode and holding down the gas pedal for approximately 10 seconds. You know it's working when the vent hose has coolant coming out of it. The reason I say this isn't really necessary is because you never really introduce any air into the cooling system like a typical fluid drain and refill situation would. As long as you keep the coolant reservoir filled you should be fine and dandy.
With that said, always be care not to overheat your engine when doing this. If it does, something is wrong. Yours shouldn't overheat in this procedure as long as it is filled with liquid. That is your priority.
|
Hello David,
Thank you for putting this innovative coolant flush tutorial together. I too was in the same boat as you with not being able to find simple way to do a full DIY Flush and bleed. My vehicle however is the 1 Series 2013 E82 N55 135i Auto.
I have a few questions about your process if you could shed some insight.
Question 1A:
I am wondering, at step 4, when you start the car, does it make sense to aim the clear hose back into the open reservoir to keep the coolant cycle going until the vehicle has reached its stabilized operating temp (95c-108c) and ONLY THEN can you be 100% sure the thermostat and thus all passageways are open in order to continue with a full flush of complete coolant system including engin block?
OR
Question 1B:
Will flushing into a bucket right off the bat with my vehicle engine starting up cold while using 10L (2.64 gallons) of room temp De-ionized water constantly poured into the open reservoir, be good enough to open the thermostat and all passage ways in the cooling system and engine block for a FULL flush before all 10L (2.6 gallons) of De-ionized water is used up and the plastic hose shows a clear flow?
You mention in this discussion to Unspec "The pump runs the coolant as long as the thermostat is open (
after warming up)"
How long does this warm up phase take?
Do you allow for a warming up phase by cycling the coolant in the system as per my question 1A BEFORE draining into a bucket?
At what point in your tutorial do you do your warming up phase?
At what point are you sure that the thermostat is open? Is there a way to know for sure?
Is this warm up phase, you speak about, which you say opens the thermostat while flushing from a cold engine using fresh ROOM TEMP de-ionised water quick enough to do a full flush with 10L (2.6 gallons) of water?
Or do you need to keep flushing with up to as much as 22L to 26L (6/7 gallons) of water before it warms up sufficiently enough to open the thermostat and thus complete the full coolant system flush and ONLY then it starts to go clear in the hose?
You said - "The N55 model engine uses 10 liters of coolant."
10 Litres of coolant being 50/50 mix I assume. So I would assume pumping 10L (2.6 gallons) through the system would mean you will get roughly 10L of the old fluids out and therefore pumping in 5L (1.3 gallons) on pure coolant in after this 10L would be accurate for a 50/50 mix.
With the above in mind and knowing the N55 can only take 10L of 50/50 mix why are you saying we need:
- [ ] 6 or 7 gallons of distilled water (22L - 26L)
- [ ] 2 gallons of OEM BMW non-diluted antifreeze (7.57L)
Surely only 5L (1.3 gallons) of non-diluted antifreeze goes in at the end of the flush ?
I will wait for some clarity before I attempt your process (with the engine running)
Thank you for taking the time,
Michael