Results 1 to 10 of 10

Thread: Please help, how to completely flush cooling system??

  1. #1
    Join Date
    Feb 2004
    Location
    Hacienda Heights
    Posts
    6
    My Cars
    BMW 330i

    Please help, how to completely flush cooling system??

    I let my friend take my car to service at this place he knows personally (big mistake) they added some aftermarket coolant. I didn't know how bad it is at first until the "radiator" light came up after 3 months of service. I searched the forums, and confirmed that he didn't get them to use BMW coolant. : Now I am woried $%&# that my car's gonna !$@#^% up. I'm gonna try to do it right this time --- by my self!

    Can anyone help me, I have a Bentley manual but it doesn't tell me anything about cooling system flush. I've read on some sites that I'm suppose to add some kind of cooling system cleaner with distilled water after draining the coolant and let the car run for 30 min with heater on and dump it followed by another distilled water fill and heat car for 5 min. Is this good or is it a really bad idea?

    Also, some sites say I can just run the hose at the radiator cap with the drain open.... I have the "hardest" water known to man, is there any other way I can do this?

    Please help

  2. #2
    Join Date
    Feb 2004
    Location
    TN
    Posts
    483
    My Cars
    97 528i AND 94 325i
    Well, if you want to get that old stuff out and you live in a WARM climate that WONT FREEZE, then you can just dump out what's in there now and replace it with DISTILLED water (walmart has it cheap). It is fine to drive it without antifreeze for a while as long as it wont freeze up on you...

    When I changed my fluid, I first replaced everything that would drain out with water and drove it for a week, then drained again and then filled it to the right mix of coolant/water.

    You might want to do the distilled water cycle a few times to get all that old stuff out. When I was running probably 80-90% (since not all the mix comes out when draining) distilled in the summer, my temps were fine...

  3. #3
    Join Date
    Feb 2004
    Location
    TN
    Posts
    483
    My Cars
    97 528i AND 94 325i
    I copy and pasted this from some stuff I have, I'm pretty sure this is in the Bentley manual:

    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 .

    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

  4. #4
    Join Date
    Feb 2004
    Location
    Hacienda Heights
    Posts
    6
    My Cars
    BMW 330i
    Thank you for your help! Running on distilled water sounds like a good plan since I live in southern California. I just have one concern, I was in an auto parts store, Kragen I beleive, I over heard the store manager talking to this guy about anitfreeze. He said that he shouldn't mix too much water with antifreeze, try to keep it at 50/50 because too much water would rust the engine. Is this true?

    Then again, I guess 1 week wouldn't hurt as much as the junk coolant thats inside my engine right now..... dunno

    I think I'll get started on that tomorrow morning. Thanks again for your help!!

  5. #5
    Join Date
    Feb 2004
    Location
    TN
    Posts
    483
    My Cars
    97 528i AND 94 325i
    Originally posted by bimmerudon
    He said that he shouldn't mix too much water with antifreeze, try to keep it at 50/50 because too much water would rust the engine. Is this true?
    I'm pretty sure that wont happen on our cars, they have an aluminum block...maybe on an iron block engine.

    The best argument to use the BMW coolant is because that fluid touches many different alloys within the engine and those alloys are subject to corrosion,etc, the BMW forumala is supposed to be formulated to better match our engines vs. regular coolant.

    You shouldnt have any problems flushing it by driving with a majority of H20. In your case, I would do the whole fill, drive, and flush with distilled a few times for some mileage to get all that other stuff out of there. Then when you are ready to refill, remember that even when you empty out the remaining fluid what is left in there will be water, so you need to account for that when you refill with a 50/50 mix. There are also engine block draining points (I didnt use these) that you might want to use, but it's up to you. I think if you run the distilled a few times through there you should be good.

    Since you dont live in a freezing area I would lean towards having too much water rather than coolant because the "coolant" really doesnt cool as well as water, it is mostly for inhibiting corrosion and prevent freezing.

  6. #6
    Join Date
    Feb 2004
    Location
    Hacienda Heights
    Posts
    6
    My Cars
    BMW 330i
    Thanks utgrad! I think I'll flush my system with distilled water for 2 or 3 times over a week or two before I put in the BMW coolant mix and probably do another coolant change in my next service intival.. 15K miles..

    Thanks again!

  7. #7
    Join Date
    Feb 2004
    Location
    Hacienda Heights
    Posts
    6
    My Cars
    BMW 330i
    Got few more questions...

    I just drained the radiator, but only about a gallon of old coolant came out. I tried to find the engine-block drain, its difficult even with the bently manual... is it the one with the allen socket? There seems to be only that screw there. Don't want to mess up and open up some unwanted stuff.

    I added about 1 gallon of distilled water in there, but I'm worried about the mixture now, because supposely the engine has 8.8 quarts coolant capacity, I removed about 3.9 quarts, and added distilled water about the same amount. Without completely draining the system, it will be hard to guess the final coolant mixture I have to put in after several distilled water flushes.

    Another thing is that coolant 50/50 mixture gives a boiling point at about 260F, which is significantly higher than 212F for water, is that gonna be a problem? Becauase if it reaches 212F, there will be a great gas (steam) build up in the cooling system.. Should I be worried about that?

    I'm keeping my fingers crossed here hope everything is ok, assumming that the old mixture is a 50/50, now I should have a mixture close to 25/75, which would mean I need to place a 75/25 mixture in if I don't do any further flushes...

    what do you think? please help. Thank you!

  8. #8
    Join Date
    Aug 2002
    Location
    People's Republic of Unit
    Posts
    5,301
    My Cars
    MZ4C, Veloster, Tucson
    The engine block drain plug is near cylinder #3. It's a 17mm drain plug not unlike the oil pan drain plug on the passenger side.

    You can't miss it. And yes, the engine side actually contains the majority of the coolant.
    "Bench racing" about track times driven by professionals are like a bunch of nerds arguing which Princess Leia is hotter, the slave Leia or the no-bra jail-bait Leia. No matter how compelling your argument is, the plain and simple fact is, none of you will EVER get to hit that.

  9. #9
    Join Date
    Feb 2004
    Location
    TN
    Posts
    483
    My Cars
    97 528i AND 94 325i
    Yeah, in your case it would probably be better to go ahead and drain the block too. When I changed mine, I was didnt have to worry about getting "bad" coolant out, so I didnt flush it as thoroughly.

    You should be able to keep a good eye on the temp gauge to see if it will get too hot. If you are getting close to a 100% water mix, just keep an eye on the temp, you should know after a few minutes of it just sitting there if the temps are going to soar. I doubt they go too high though...

    Anyway, once you get it close to a 100% H20 mix, you can then just drain it all out and replace it with the 50/50 and you should be good to go.

  10. #10
    Join Date
    Apr 2002
    Location
    Virginia
    Posts
    419
    My Cars
    See my sig.
    Originally posted by The HACK
    The engine block drain plug is near cylinder #3. It's a 17mm drain plug not unlike the oil pan drain plug on the passenger side.

    You can't miss it. And yes, the engine side actually contains the majority of the coolant.
    Just did it this weekend on my 00 323i. I had a 13mm drain plug that was directly underneath the #2 cylinder.
    Joe
    03 E39- S62B50 w/ 80K
    00 E46/4- M52TUB25 w/ 155K
    99 E36/8- S52B32 w/68K
    97 Ford F150 w/223K
    95 E36/C- M50TUB25 w/ 222K

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •