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Discussion Starter #1
Time for me to flush my coolant. I have heard that we need to use the special BMW coolant because of some type issue with the seals in our system that is not compatible with regular antifreeze? Also, any tips on how to flush the system?................I have done this on other cars, but you never know about BMW's, sometimes you need to know a special tip. Thanks.
 

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Discussion Starter #2
:dunno:
 

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Krix330cic(NJ) said:
we need special fluid?? i just topped off the other day at the gas station, when my low fluid light came on..... am i screwed? :dunno:
Hmmm, I wasn't aware of that one either. It's been prestone coolant and distilled water for me the past couple of times. No probs yet.
 

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Hey, I just picked up my mtech bumper and rear trunk spoiler from the dealer and I talked to the mechanic about this. He said that you do need to use their "specially formulated" BMW coolant in our 50/50 antifreeze/water mixture because the seals in the water pump and thermostat will go bad if you use regular antifreeze (didn't say exactly why tho). He also said that they replace a lot of thermostats and water pumps for this very reason. He said the manual says to only use the BMW coolant (but I always thought they say that so you would spend the extra cash on the BMW stuff) :dunno:

He also told me how they do the "flush". They drain a little more than half of the coolant out and then retighten the drain valve and add a 50/50 mixture of the BMW coolant/water. Then you run the engine until the coolant starts to circulate for a while (this is the "flush"). He even said that it would be better to run the car for a day or 2 for this step. Then you drain the coolant all out and replace with another 50/50 mixture of BMW coolant/water.

Either way he sold me 2 gallons of the BMW antifreeze/coolant for $11.97 a gallon. :tsk: I have read about this in other posts so I don't think they were BSing me.
 

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According to my Bentley you should use a coolant that is phosphate free, which is what I assume BMWs is. If you got phosphate free you should be fine, if it has phosphate you should change it out.

Tim
 

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I just check to see if the prestone stuff I used is phosphate free and the answer is no but here's their response (posted on their website):

Q: Does Prestone® Antifreeze/Coolant contain phosphates?
A: Some European automobile manufacturers request that a phosphate-free antifreeze be used in their vehicles. This issue is related to the extremely high mineral content of the water in Europe. If you were to mix an antifreeze that contained phosphates with the type of water they have in Europe, it may produce deposits that can settle in the cooling system and promote corrosion. However, in North America we do not have this type of water problem. Typical North American coolants have contained phosphates (which is part of the corrosion inhibitor package) for many years. Therefore, the question of phosphates is a non-issue here in North America. Prestone® Antifreeze/Coolant is completely safe for use in both foreign and domestic vehicles. For those consumers who would feel more comfortable using a phosphate-free antifreeze, our Prestone® Extended Life 5/150 Antifreeze/Coolant is phosphate, silicate, and borate free. This coolant uses a special chemistry and technology that extends the life of the corrosion inhibitor package so that it lasts for five years or 150,000 miles (whichever comes first), and is safe for all cars and light trucks (old or new). Prestone® Extended Life 5/150 Antifreeze/Coolant has been approved by General Motors under their DEX-COOL® specifications and is compatible with other DEX-COOL® approved coolants.
 

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Discussion Starter #8
Wow Keeferno, great information. Thanks for looking this up. I guess that explains it. So, does anybody want to buy my $12 a gallon BMW coolant? :D

Of course there was also the dealer mechanic who told me that they get a lot of bad water pumps and thermostats because people don't use the BMW antifreeze. :eek:
 

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Discussion Starter #10 (Edited)
OK, I did the flush. This is what I did:

I used the Bently manual and pretty much followed its instructions. I might add that the Bently manual notes the following- "Always use BMW coolant or its equivalent to avoid the formation of harmful, clogging deposits in the cooling system. Use of other antifreeze solutions may be harmful to the cooling system".

1) I purchased 2 gallons of the BMW coolant from the dealer.

2) Raise the front of the car and support safely.

3) Remove splash shield from under the engine.

4) Loosen radiator bleed screw at top radiator fitting.

5) Remove cap from radiator expansion tank. Set temperature controls to full warm.

6) Place 3 gallon pail underneath radiator.

7) Remove drain plug on bottom of radiator. (there is another step to remove the engine block coolant drain plug on the exhaust side of the engine and drain the coolant in the block..............but since I was doing a "flush" I did not do this).

8) Drain about 1 gallon of coolant. ( I also removed the expansion tank drain plug and drained some coolant from there as well). Reinstall the drain plugs (radiator drain plug: 18 to 27 in-lb) thats inch-pounds not foot-pounds :rolleyes: .

9) Mix a gallon of coolant and water (distilled water if you are really picky).

10) Before refilling the radiator, turn the ignition to "on" (do not start the car), set temperature controls to full warm (should already be there from before), and set blower control to low.

NOTE: Air may become trapped in the system during cooling system service. Trapped air can prevent proper coolant circulation. Whenever the coolant is drained and filled, the system should be bled of trapped air.

11) Loosen the bleed screw and slowly fill the expansion tank until the coolant spills from the bleed screw. When coolant spilling from the bleed screw is free of air bubbles, tighten the screw and the expansion tank cap.

12) Run engine until it reaches operating temperature. After engine has cooled, recheck coolant level and top off so that coolant level indicator is at "max".

13) You can either let the engine run for a while or what I did was leave it in the car for a day of normal driving (this is the "flush" suggested by the BMW mechanic).

14) Let engine cool off and drain all of the coolant this time from the radiator and the expansion tank. Repeat steps 10 through 12. :thumbup:
 

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The Prestone explanation is BS. Every BMW I've worked on where phosphate-containing coolant was used had all kinds of mineral buildup in the cooling system. While it's not necessary to use the BMW coolant, it is necessary to use phosphate-free stuff, like the Prestone Extended Life. The most notorious coolant is the normal Prestone green stuff.

The BMW tech is right, the water pump is usually the first thing to go.
 

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markusmark said:
Go with the BMW coolant and distilled water. Prevention is cheaper than repairs!:D
The coolant should be flushed every two years. Even tho the BMW coolant is a couple extra $$s, it's worth it for the peace of mind. Come on, what's any extra $10-$20 every two years? If you can't afford that, you've got bigger problems!

Regards,
Steve
(who changes all fluids annually, just for extra extra peace of mind)
 

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Just some advice and observations from my coolant flushing experience this weekend:

1. The engine coolant drain plug is located on the passenger side of the engine block just in front of the exhaust manifold. The bolt has a 13mm head (I saw somewhere else that said 14mm but mine....2000 328i....was a 13mm head for sure). You might want to get the crush washer before you do the job but I reused the old one and it did not leak. Torque the bolt to 25 N-m per the BMW service manual.

2. DO NOT OPEN THE ENGINE DRAIN PLUG laying under the passenger side of the car (with your legs under the front passenger door). This is an excellent way to get hot coolant up your nose, in your mouth and in your hair....wonder how I would know???? Anyway.....you can reach that bolt easily with your legs out the front of the car and much less coolant splashes/drains that direction. If you had a lift it would be very easy, but with just a jack it was a little bit of a pain.

3. I drained everything completely, filled with anitfreeze/distilled water (BMW brand), and then drove around for a while. I then repeated the etire procedure. It was much easier the second time around.

4. There is an O-ring on the radiator drain plug and a sealing washer on the bleed plug that you might want to replace while doing this. I didn't replace any of these (because I didn't know I was going to need them) and I didn't have any leaks. Still....cheap insurance if a dealer is close by to get the parts.

5. Removing the under tray is a snap (IIRC 6 phillilps head screws and three plastic rivets). The rivets can be removed by using a pair of pliars to pull the center plug down and the rivets pop right out. It would be easier to remove that center plug with a notched tool like you use to pop off door panels but I didn't have one handy and the pliars worked fine. By the way.....dogs like to eat these rivets and sip the coolant....keep dogs away from both....again...wonder how I would know this?????

6. One gallon of coolant and one gallon of distilled water will completey fill the cooling system. I flushed with coolant/distilled water so I used two gallons of coolant and two gallons of distilled water.

In conclusion, be careful, take your time, watch out for the coolant coming out of the engine drain plug, don't over tighted the plastic radiator and coolant tank plugs, and be sure to bleed all the air out of the system. Having completed this procedure once, the second time around took less than an hour including reattching the undertray. The first time took 2.5 hours...including a stop for a shower...see above....and about 45 minutes trying to figure out how to get the car up in the air (my ramps are too steep for the front spoiler). Good luck to you....send me an email if you are attempting this for the first time and you have any questions.

Todd
[email protected]
 

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Anyone knows how much coolant exactly the system have? They sell anti-freeze in 1.5 litres bottles here, so I do not know how much to buy. 3l that's makes 6l of coolant, is that enough? I think system can have more than 6l....
 

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shd said:
Anyone knows how much coolant exactly the system have? They sell anti-freeze in 1.5 litres bottles here, so I do not know how much to buy. 3l that's makes 6l of coolant, is that enough? I think system can have more than 6l....
You can do unit conversions at this website:
http://www.onlineconversion.com/volume.htm
2 Gallons is more than enough...................I used a little over 1 Gallon.
 

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I know about unit conversion. As you said you have used a little over 1 gallon. 1 gallon is 2.5 of 1.5L bottles. So how much is that "a little"? I do not know how much to get, 3 or 4 or maybe 5 bottles. I just do not want to buy more than I need.
 
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