S55 Engine Coolant Flush DIY?

[jmciver]

So I have been following the Mike Miller "old school" preventative maintenance plan on my M3 ever since I got it and it is about time to replace my engine coolant in accordance with that plan (every two years - my car will be two in a month). I have seen the BMW factory procedure, which just has you disconnect the lower radiator hose. This will obviously drain the radiator and some of the engine block, but I suspect there will still be a decent amount of old coolant remaining in the system.

So my question is, has anyone ever completely drained and flushed the S55 engine coolant system? If so, any pointers (to include the location of an engine block plug if there is one)? Is it possible to use the two electric water pumps in the coolant system (the one for the turbos and the one for the heater core) to help flush as much coolant out of the system as possible (like possibly using the bleed procedure to turn on the electric pumps in the system or some other ISTA procedure to manually turn on the pumps)?

I found some stuff on the N55 during my search, but while the S55 is based off of the N55, there are still plenty of differences that could make this process different enough for the S55.

Thanks!

[climax_e92]

I would like to know this as well. My gf's 15 m3 just hit 50k miles and i plan on doing this along with changing diff and trans fluid.

[richf80]

Originally Posted by jmciver

So I have been following the Mike Miller "old school" preventative maintenance plan on my M3 ever since I got it and it is about time to replace my engine coolant in accordance with that plan (every two years - my car will be two in a month). I have seen the BMW factory procedure, which just has you disconnect the lower radiator hose. This will obviously drain the radiator and some of the engine block, but I suspect there will still be a decent amount of old coolant remaining in the system.

So my question is, has anyone ever completely drained and flushed the S55 engine coolant system? If so, any pointers (to include the location of an engine block plug if there is one)? Is it possible to use the two electric water pumps in the coolant system (the one for the turbos and the one for the heater core) to help flush as much coolant out of the system as possible (like possibly using the bleed procedure to turn on the electric pumps in the system or some other ISTA procedure to manually turn on the pumps)?

I found some stuff on the N55 during my search, but while the S55 is based off of the N55, there are still plenty of differences that could make this process different enough for the S55.

Thanks!

Same here... bump.

[guidance]

Can't find any coolant flush interval recommendations from BMW. Even out to 120k miles.
https://www.bmwcharlottesville.com/s...esville-va.htm

[jmciver]

This is about as close to any "official" guidance you will see....

https://www.newtis.info/tisv2/a/en/f...-check/1DUJMrq

But even then it says that due to "technical progress" coolant replacement is not necessary beginning with gas powered vehicles produced after 3/2003.....

[Alpine_F82]

Originally Posted by jmciver

This is about as close to any "official" guidance you will see....

https://www.newtis.info/tisv2/a/en/f...-check/1DUJMrq

But even then it says that due to "technical progress" coolant replacement is not necessary beginning with gas powered vehicles produced after 3/2003.....

Yep no need to do a coolant flush just put it in and keep on going
That’s what I like about new cars but this still gets me mad on my old Ferrari

[mrrm3]

our cars (i.e., old-school), has anyone figured out a way to drain all the coolant ?

I read Dinan's instructions for changing out the radiator, which starts w/ removal of the hose near the bottom of the radiator on the passenger side, but I only managed to drain about 1/4 gallon of fluid.

What is the trick for draining the entire system (which I believe is close to 2 gallons) ?

(Thank you in advance for not telling me a coolant flush is unnecessary.)

[SD ///M4]

I don't know what the "recommended" method is, but a few decades ago I used to do a drain and flush on my cars by pulling the lower radiator hose, sticking a garden hose into the upper radiator hose (before overflow tanks) and then just running the engine until everything came out clear. Then you stuck the hose into the upper radiator and flushed it until it was clear.

I suspect that's not the way it's done now...

[jmciver]

Originally Posted by SD ///M4

I don't know what the "recommended" method is, but a few decades ago I used to do a drain and flush on my cars by pulling the lower radiator hose, sticking a garden hose into the upper radiator hose (before overflow tanks) and then just running the engine until everything came out clear. Then you stuck the hose into the upper radiator and flushed it until it was clear.

I suspect that's not the way it's done now...

In theory, that basic process could work. But the cooling system is more complex now with several more "nooks & crannies" that would make flushing the system that way a bit harder (but not necessarily impossible).

I actually broke down and had the dealer do it when my car was in for routine maintenance. They have a machine that takes a suction on the cooling system to get the old coolant out and new coolant in, similar to the one in the video below...

https://www.youtube.com/watch?v=LBYJ_9Q0m0w

Since the coolant in my car is not "old & crusty" I am not worried about any of the residual coolant that may remain in the system after using this method since essentially all of the old coolant will be removed from the system. The dealer charged me ~$200 which was an easy sell for me - at least for now.

When my next coolant flush will be due, which will be in 2 yrs, I will look deeper into doing it myself.

[Karlosm2c]

Sorry for hijacking this thread, but it's in the same ball park and I thought some of you could help.

One of the other UK Bimmerpost members mentioned yesterday that his coolant levels were low after picking up his M2 Comp so I checked my level also after picking up my M2 Comp on Friday and mine was also low, so I topped it up to recommended levels.

I then later in the day drove about 10 miles to pick up a pizza and as I pulled in to the car park the engine was steaming. I looked under the bonnet and at that point I saw the coolant cap sitting in the engine bay where I left it as well as coolant spluttered all over that side of the engine. I know, I know, stupid mistake (I still can't believe I did this).

I followed the trail of coolant and it looked like it only started leaking from the engine 150 feet away from where I parked my car. After picking up the pizza I put the cap back on, drove it home at the lowest revs possible and used a cloth to clean up all the coolant I could reach and then left the car to cool down.

I have been reading that I should bleed the coolant system and I have seen some guides on this, but only for older BMWs. / M cars. Can you guys please advise me what I should do? If any one could show me a picture of where the bleed screw is explain what I need to do to bleed the system I would massively appreciate it. I have seen on the internet that I might have to turn the ignition on, put the heating on high, etc, etc, but a detailed response would help.

I am taking my car 50 miles to get some parts added tomorrow so I'd love to get this sorted today. Would it be ok to simply top up the coolant, drive the car and get them to sort this out? I would rather do it myself today if I had the right guidance.

I feel pretty dumb for making such a rookie error, but hey-ho, you learn from your mistakes and all that.

Cheers,

Karl

[jmciver]

There is no bleeding screw on the S55. You should be fine with just toping it up with distilled water. Running the bleeding procedure would not be a bad thing. The factory procedure is below....

https://www.newtis.info/tisv2/a/en/f...eck/1VnXqfU9E9

[kosd]

Originally Posted by SD ///M4

I don't know what the "recommended" method is, but a few decades ago I used to do a drain and flush on my cars by pulling the lower radiator hose, sticking a garden hose into the upper radiator hose (before overflow tanks) and then just running the engine until everything came out clear. Then you stuck the hose into the upper radiator and flushed it until it was clear.

I suspect that's not the way it's done now...

I think the easiest way to do a flush these days is to drain from the plug and radiator hose (if easy enough to disconnect). Then fill the system with a couple of gallons of distilled water, run the car with heat on high for 10 min and then drain/refill with the appropriate antifreeze.

Personally, I’d probably avoid puttingbtap water in just to prevent any minerals from staying in the system, although it would probably be minimal.