Quote:
Originally Posted by iQuick
Quote:
Originally Posted by Surly73
I like that common sense is on the list of required items 
A weakness that I see in this process is the fluid in the radiator loop. The coolant system isn't a single loop, there are branches all over the place and one of these is the entire radiator. The thermostat needs to be open to ensure you've got proper flow here.
With every inline 6 BMW I've worked on, (M52, M52TU, M54, N52, N55) I have found that even in the summer heat when it's just idling and I have the hood up it sheds enough heat to the environment that the thermostat doesn't even necessarily open. (stop and go traffic in the blazing sun with the AC on is a different environment than idling in the shade in my garage with everything off and the hood open). On the N series engines with electric water pump, if the weather is cool the pump might not even run!
So - I can't conclude your method won't work or anything like that, but it would be a serious reservation on my part. Now - I would assume that the fancy-pants BMW bleed program would force the thermostat open. I wonder if your method would work better if you just connected a charger/power supply and used the bleed program to circulate instead of running the engine? Less risk of burns etc... too.
Related - for a couple of decades I've always tried to change fluids more often than manufacturer recommended. Often with fluids anywhere in the driveline (brakes, transmission, clutch, steering) I can observe improvements in the system after changing the fluid even when I do it "too often". One advantage of doing this is that one doesn't need to feel desperate to get ALL of the old fluid out. When I use a turkey baster to extract and replace all of the power steering fluid once per year or every other oil change or whatever, I don't need to get all stressed about removing every drop of it. What was left in the system is still "good enough" and will blend with the fresh fluid. Same for coolant, transmission, you name it. Taking this approach often means it's an easier job to do (e.g. turkey baster power steering reservoir and then refill instead of pulling banjo bolts at the rack to get every drop out)
Now - you found what appeared to be incorrect fluid so what I just said doesn't apply 
Thank you for devising and posting and innovative way of performing this job, which BMW really made a PITA on the F10 by eliminating some drains and requiring a vacuum apparatus to refill. |
Hello Surly73,
Did you ever try this method of coolant flushing that David put together or a variation of it?
I am also wondering if the BMW bleed program would do the same job but better?
Or if not as per Unspec's trial of it then a hybrid version of the two ?
Michael |
Sorry for the late response. I'm no longer on the forums as much because my engine spun a rod bearing and seized. Had to sell it as is. Regarding your question. I really can't remember the specific details because it was so long ago. I believe that if you want to be 100% sure of all coolant passageways being circulated, I simply turn the car on with the hood closed and let it idle until it reaches operating temperature (I know the temperature gauge measures oil but the process still applies here). After it reaches operating temperature I would turn off the car. Now you can open hood and get the hose apparatus and bucket ready so that coolant can drain into the bucket. This means taking off the bleeder hose and connecting a hose to it into a bucket to drain out. I would then open the reservoir. Start the car and watch the coolant drain out. You will want to monitor the coolant level and begin filling up with distilled water only. For me this took some time until my hose going into the bucket turned clear. Once you start seeing clear, go ahead and pour in your coolant concentrate. Pour until the water coming out of the hose is looking blue. That's when I would stop the car and close everything back and and top off with 50/50 accordingly to make sure the level is correct. Then just to make sure. I would restart the engine and let it idle with the hood closed. After around 5 minutes or so I would check the level and check the coolant with a gauge that tells you what temperature it protects up to.
Hope this helps.
You could also just do the same process without turning the engine on. Just engage the bleeding procedure and see what comes out and how much. I can't guarantee you'll get a perfect flush but most of the old will be out. My bleeding process went around 20 minutes when I tried it.