Coolant flush conundrum

[ionofchios]

Just been flushing coolant on my manual e85 3.0si (N52). This is the first time I’ve done this, and I was following a how-to that recommended not removing the block drain plug, since it is alloy and one-use only, and, worse, apparently block threads can even get damaged. Anyways, my objective was to flush out the whole system and replace the strange orange stuff that was in it with BMW blue.

I removed the 2 radiator-related blue plugs and drained everything out. Then filled with distilled watered and did the trick where you turn ignition to stage 2, turn up heater and press accelerator for 10 seconds, which puts the water pump into some burping/service cycle. Left it for ten minutes, topping up with distilled as needed, all that stuff, and it squirted through quite a few times. I did this flush procedure 2 or 3 times in total, going through about 15 L of distilled.

After that, I drained it again from the blue plugs, then made my mistake Somehow, I had remembered that the capacity of the cooling system is 10 L, so I tried to put 5 L of straight coolant in, figuring that there was about 5 L of pretty much pure distilled water left in the system. But, I only managed to get to about 4.75 L of coolant in before it was full. Then I had a read around, and found that the capacity is in fact 8.2 L - though there does seem to be some lack of concensus on this matter.

So, what should I do now? Is the ratio that important? According to my calculations, I’ve got about 4.6 L of coolant and 3.6 L of distilled, assuming all the orange stuff is basically gone.

Also, does running the water pump with the above procedure actually cycle the whole system, including the block? Am a bit worried that I’ve only flushed half the system.

All in all, seems like it would have been easier to remove the block plug and replace with a new one, then fill with actual 50:50 mix.

 

[ionofchios]

This is probably where I got the 10 L idea from: https://www.pelicanparts.com/techarticles/BMW_Z4M/15-WATER-Draining_and_Filling_Cooling_System/15-WATER-Draining_and_Filling_Cooling_System.htm. This is not the how-to I followed, though - I used this one: http://www.zpost.com/forums/showthread.php?t=488476.

 

[ionofchios]

Hold on, does N52 even have a block drain plug? Are you supposed to detach hoses or something?

 

[Davz]

No block drain plug on an N52 and yes you are supposed to detach the lower radiator hose that fits into the thermostat housing, b*gger of a job mind you!

 

[ph001]

I wouldn’t worry about your ratio at all. Not critical.

 

[ionofchios]

Ok, cool. Sounds like I’m probably okay then. Next time I do this I’ll try detaching a hose as well.

 

[Ducklakeview]

Anything above 25% should be fine in the UK, even at the temps we've had the last few days. However due to the magnesium/aluminium construction of the N52 block, I would stick with the ratio prescribed by BMW for the sake of corrosion protection. You can buy a cheap tester like this;



http://www.halfords.com/motoring/engine-oils-fluids/antifreeze/halfords-antifreeze-tester-meg?cm_mmc=Google+PLA-_-Engine+Oils+and+Fluids-_-Antifreeze-_-527374&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=litpqx&istBid=tztx&_$ja=tsid:94971|cid:865695751|agid:43902126215|tidla-425552236234|crid:202397318361|nw:g|rnd:7850556647221660274|dvc:c|adp:1o2|mt:|loc:1007230&gclid=CjwKCAiA8vPUBRAyEiwA8F1oDPSU_4InM_UwWL1s_RY0W30pITpUun3f9pKK9TByeaQv_QhK55LBuxoCLNEQAvD_BwE

Use it to check the concentration, if more is needed, simply draw some coolant out of the expansion tank, add antifreeze, go for a drive and re-check.

When filling an N52 6 pot, I use the BMW recommended procedure, which involves pulling a vacuum on the cooling system and then allowing it to suck the coolant in using said vacuum, however most people won't have access to a vacuum filler. Can't really see that being a problem as you've used the correct bleeding procedure by operating the pump. Just out of interest, did you connect a power supply/charger to the car when doing it, as that's what's recommended. I use a diagnostic support unit which supplies 25a @ 14.5v to stop the battery draining, did yours complete the cycle on battery power alone?

Mike

 

[ionofchios]

Anything above 25% should be fine in the UK, even at the temps we've had the last few days. However due to the magnesium/aluminium construction of the N52 block, I would stick with the ratio prescribed by BMW for the sake of corrosion protection. You can buy a cheap tester like this;

anti.jpg

http://www.halfords.com/motoring/engine-oils-fluids/antifreeze/halfords-antifreeze-tester-meg?cm_mmc=Google+PLA-_-Engine+Oils+and+Fluids-_-Antifreeze-_-527374&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=litpqx&istBid=tztx&_$ja=tsid:94971|cid:865695751|agid:43902126215|tidla-425552236234|crid:202397318361|nw:g|rnd:7850556647221660274|dvc:c|adp:1o2|mt:|loc:1007230&gclid=CjwKCAiA8vPUBRAyEiwA8F1oDPSU_4InM_UwWL1s_RY0W30pITpUun3f9pKK9TByeaQv_QhK55LBuxoCLNEQAvD_BwE

Use it to check the concentration, if more is needed, simply draw some coolant out of the expansion tank, add antifreeze, go for a drive and re-check.

When filling an N52 6 pot, I use the BMW recommended procedure, which involves pulling a vacuum on the cooling system and then allowing it to suck the coolant in using said vacuum, however most people won't have access to a vacuum filler. Can't really see that being a problem as you've used the correct bleeding procedure by operating the pump. Just out of interest, did you connect a power supply/charger to the car when doing it, as that's what's recommended. I use a diagnostic support unit which supplies 25a @ 14.5v to stop the battery draining, did yours complete the cycle on battery power alone?

Mike

Wow, didn’t know you could get a tester. I will get one of those!

I ran that pump flush procedure 3 times all the way through (10 mins each) on battery alone.

 

[Magicarcher]

It won't help you much now but for the future, find the capacity (using BMW technical documentation preferably). Drain fully, flush, put all hoses etc back on and fill with half the quantity of anti-freeze, then top up with water of your choice (now there's a discussion) and bleed. You should then end up with 50/50.

 

[Scooba_Steve]

I'm still struggling to find the capacity on TIS!

 

[Magicarcher]

I'm still struggling to find the capacity on TIS!

According to my BMW handbook page 103 my 3.0L manual is 8.3 litres.

 

[Scooba_Steve]

N52, so not sure if it's different.

 

[srhutch]

Manual 7.6, auto 8.4 according to the USA manual for the 3.0si

 

[ionofchios]

https://www.newtis.info/tisv2/a/en/e86-z4-3.0si-cou/repair-manuals/17-cooling/17-00-cooling-check/6sPlo5g

I just found this, which is supposed to be for 3.0si Coupe, meaning N52B30 - 8 L for manual with air-con. So, again different from other sources I’ve found.

 

[ionofchios]

And, who’d have guessed, but paper manuals have information, too! Here’s the spec from the original manual for my car:

 

[ionofchios]

So, my italian’s not great, etc, but I guess that says 7.6 L. Looks like a have too much coolant, definately.

 

[ph001]

If you have too much, doesn't it just overflow the expansion bottle?

 

[ionofchios]

If you have too much, doesn't it just overflow the expansion bottle?

What I mean is I have too much antifreeze and not enough distilled water.

 

[ph001]

Ah, i see. It will be fine, really.

 

[ionofchios]

Yeah, I think you’re right. I calculated that, assuming my process flushed out all the old coolant and system volume is 7.6 L, I now have 60:40, antifreeze:distilled. I read a paper somewhere that ethylene glycol actual starts to decrease in effectiveness past 60% concentration, meaning past that the temperature at which the coolant freezes starts to get closer to 0 degrees C again.