Coolant Question.

[audi666]

Sorry new here, just fixed a coolant leak and need to refill a bit.

I was just wondering what type of coolant do most people on here use?

Do you use oem and mix 50/50?

Thanks

[JackBennett]

BMW Blue 50/50-ish in the winter and straight distilled water in the summer for Seattle Washington.

I don't know if it's true or not but my grandfather used to say that plain water will cool much better. I've always done it. I figure if nothing else it make for a clean system by draining and refilling it every 6 months or so.

my 2 cents.

[SteveJ]

50/50 mix of BMW blue coolant (Smurf juice) yearround here in the SF bay area.

The only time I have deviated from a 50/50 mix is when I find the radiator is a bit low and all I have is distilled water. Just kept topping it off until I could get it fixed.

As I understand cooling systems, a pressurized system will cause the boiling temp to be higher. So make sure the hoses and clamps are in tact, and the radiator cap seals up to the correct pressure. Adding in coolant will also help increase the boiling temp as well as adding lubrication for water pumps. Glycol is slippery stuff. It also gives the Smurfs somethng to do since their show was cancelled.

[JFT]

With respect to both you and your grandfather, you may be asking for trouble by putting straight water into your car's cooling system during the summer - or at any other time. The block is cast iron, the head is aluminum. Aluminum can, and will, corrode, with straight water. I know this from personal experience, I'm afraid. Mike Maccartney's restoration book has photos of heads that have been so treated. These photos show significant corrosion of the water passages in the head. When they corrode sufficiently, the head-gasket blows out. Expen$ive. That's why a 50-50 mix of water and antifreeze is recommended by all manufacturers these days.

[Napes]

I, too, use BMW blue coolant mixed 50/50 with distilled water year-round here in the desert. But, as I mentioned in a post awhile ago, I live at 4,000 ft. elevation and winter mornings are often below freezing. Also, as stated above, you do not want to run straight H20 in an aluminum head, unless internal corrsion is of no concern to you.

Bob Napier

[audi666]

Alright thanks for the info.

I'm not sure whats in it right now buts its green coolant. Where is the best place to pick up the blue coolant?

Also is it best to top it off with distilled water and wait to flush it with a 50/50 of the Bmw blue coolant or top it off with the 50/50 blue coolant since its a little low and Id like to get it topped off.

[Guest Anonymous]

get an antifreeze tester for a few bucks so you can tell how much freeze protection you have - then add straight green coolant or straight distilled water, depending on the strength of what is in there. Once you have the super special coolant you want (I"ve used brand name green stuff for 40 years with no problems, so I think it is overkill to pay a lot for BMW blue), flush the system and start fresh, always using distilled water.

[Guest]

Pentosin sells blue (VW/Audi = G11) and pink (VW/Audi G12) antifreeze for somewhat less than the oem stuff. As I doubt BMW or VW/Audi make their own coolant, it's probably Pentosin or another commercial polyethylene glycol blend; maybe BMW add some secret sauce to theirs, don't know. Also heard that WaterWetter provides corrosion protection if you don't want or need to use glycol; it's used in race/track cars that can't use glycol but they probably change coolant very often; more environmentally friendly, for sure, as ethylene glycol is pretty toxic.

[ingraham]

BMW's blue antifreeze is excellent, and it's the only kind you should use in a modern (with plastic & aluminum radiator) BMW.

For older cars (with copper, brass, & solder radiators) I recommend a name brand ethylene glycol antifreeze, such as Prestone or Zerex. Recycle the old stuff properly.

Which ever antifreeze you use, change it every two years, and mix it 50/50 with distilled water. Don't cheap out here -- it's only a dollar fifty for two years' worth. If you start with a gallon each of antifreeze and water in a bucket, you will have 1-2 quarts left over; put it in an empty jug, mark it "Mixed 50/50", and use it for top-ups.

Don't mix different kinds of antifreeze. Don't use just water except in an emergency; you need the lubrication and anti-corrosion components in antifreeze.

When draining the radiator, I strongly suggest removing the lower hose rather than the drain plug. The tank material around the drain plug bung is weak and easily broken. Also, the hose drains faster.

After draining the radiator, drain the OTHER HALF of the coolant from the engine block by removing the block drain plug below the freeze plug below the #4 spark plug: http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/topic_view,threads/p,649407/t,329374/ (Thanks, Bill Williams)

Use new crush rings on the drain plugs.

[M3M3]

you can use just water...IF you dump a bottle of something like redline waterwetter in with the water. adds the lubricity. this is the norm for track and race cars. coolant is dangerous on a track. my e36 race car engine has not seen coolant in 6 years.

[Arshloch]

Preston yellow stuff:

30-40% in the summer

50-65% in the winter

changed every year.

Keep in mind that the conventional and long-live coolants are different in terms of corrosion effects to the radiator joints of the brass/cooper units. The green stuff will corrode it real quick if left for too long (the system will self plug up). As far as I know, the newer stuff is superior in lubrication of the pump seals.

The key is in changing it regularly.

I am pretty sure there are some awesome diesel related tricks that can be done to the coolant!?

[JackBennett]

Interesting... I had never though that my 'paps advice came from the days of iron flatties. Things change... much like my anit-freeze usage will as of now. Makes sense as soon as someone says it.

[Arshloch]

The oem manual states that you can run straight water in there, as in the good old days, many indeed did that. But, back than, motors would not be guaranteed to last as long as they have actually done. An average Fiat motor would barely last 70K, and a Lada 40K. Many a car owner in Eastern Europe still commit to water use in older cars.

[Guest Anonymous]

BMW's blue antifreeze is excellent, and it's the only kind you should use in a modern (with plastic & aluminum radiator) BMW.

I use the search function for common questions such as this. There are plenty of posts covering this issue, including this one: http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,292205/

In that post, you mention G-05 which I think Mercedes uses. Is it the same or better as the BMW/Audi Blue? Since I use a Behr plastic/aluminum radiator, should I use it, or does it really matter? Seeing as many radiators as you do, have your opinions changed over the years?

Thanks.