BMW coolant qualities - any mythbusters?

[John in VA]

For piece of mind, I've been using BMW's coolant in the 2002tii, E30 and E28. Then I run across this quote on a 2002 forum. Any opinions/info?

"The expensive mysterious BMW blue coolant is actually BAD for any plastic cooling system parts, so if you have an e21 plastic-tank radiator (or any newer BMW you intend to keep past warranty) I personally would FLUSH IT OUT and get some prestone or other universal coolant which does not contain the evil 2-EHA plasticizer that BMW uses, and paradoxically eats their plastic cooling system parts from the inside out."

[Shawn D.]

... piece of mind...

I would be on the path to inner peace if folks would learn the differences between homophones.

As to the coolant, IF that's true, I'd take degraded plastic over degraded heads, blocks, and radiators any time.

[Tammer in Philly]

The quote is wrong. The BMW coolant (and Mercedes blue and other G-05 coolants) is lower pH than most off-the-shelf stuff, which is strongly basic. The more neutral pH is gentler on the plastics, but primarily it is better for the heads as hydroxide and aluminum are not friends.

-tammer

[John in VA]

... piece of mind...

I would be on the path to inner peace if folks would learn the differences between homophones.

Shawn - that was for you! We're speaking the same language. Over lunch I had the chance to read a lot of posts on several forums and was just keeping up!

Maybe we should make mastery of these errors (link below) mandatory before one is allowed to post!

http://www.wsu.edu/~brians/errors/errors.html#errors

[a]

I have used nothing but various brands of the cheapest anti freeze I can find for over a decade and havent blown a headgasket yet. I also cut it with plain ol' well water. I do, however drain and flush every 2 yrs, whether it needs it or not.

[RonW]

I have used nothing but various brands of the cheapest anti freeze I can find for over a decade and havent blown a headgasket yet. I also cut it with plain ol' well water. I do, however drain and flush every 2 yrs, whether it needs it or not.

As a data point, I just blew a head gasket on the 535i, with 425k miles, and I use regular green antifreeze. Actually, "blew" is overstating it; it developed an external coolant leak, and I could keep driving as long as I was willing to add coolant daily. The head needed to be machined, and of course the gasket was toast.

[a]

I have used nothing but various brands of the cheapest anti freeze I can find for over a decade and havent blown a headgasket yet. I also cut it with plain ol' well water. I do, however drain and flush every 2 yrs, whether it needs it or not.

As a data point, I just blew a head gasket on the 535i, with 425k miles, and I use regular green antifreeze. Actually, "blew" is overstating it; it developed an external coolant leak, and I could keep driving as long as I was willing to add coolant daily. The head needed to be machined, and of course the gasket was toast.

no worries mate. My new 88 has about 128 k miles. Marina's just 122k. We can rack up a few more miles before we gotta start worrying.. I am heartened to see that your 86 is still carrying you back and forth.

[Mike W.]

I have used nothing but various brands of the cheapest anti freeze I can find for over a decade and havent blown a headgasket yet. I also cut it with plain ol' well water. I do, however drain and flush every 2 yrs, whether it needs it or not.

That's what I do. Maybe not the cheapest, but the cheapest without silicone silicate, which I've heard is bad for aluminum, and may even be discontinued now. Same results too, no problems.

[alijonny]

keep the coolant flushed and it won't become acidic and yellow things/ break down plastics and gaskets. If you think your coolant is okay and you haven't changed it in a while, take a multimeter, put one end in the coolant, and ground the other on any common ground. set it on the mV setting and watch the voltage in the fluid. for cheap insurance I only put BMW blue in my cars. I think it is better than green, and it shows that I am a real enthusiast (lol).

[motosys]

I have been using prestone for years and years and years no issues. I am too lazy to mix antifreeze / coolant so I spend the 15 bucks and buy a gallon of 50/50. And I fulsh my coolant every 2 years or so except on my newer vehicles that came factory with the orange coolant that lasts 5 years

[schwarzie]

Does anyone have any pics of corrosion or pitting on an M30 or M20? I've seen pics of pitting on the head of an M42. Anyone have any links to any TSB's regarding the subject? Heres one I found after a quick Google search -
http://bimmer.roadfly.com/bmw/forums/e39/9035566-1.html

[shagrath]

Jay used blue... and so I continue to use blue. He says it also helps the system stay a little cooler too... but I don't know about that. I don't mind using it especially cause I get it free from a girl that works for the local BMW/Mini service dept as a tech on Mini's.

[Son of a]

Jay used blue... and so I continue to use blue. He says it also helps the system stay a little cooler too... but I don't know about that.

I second your skepticism. Even if the blue juice does somehow keep the cooling system cooler, its not like the e28 needs it. I run cheap green antifreeze mixed 50/50 with tap water in my M30 and have zero problems with the car running hot. This is in a vehicle without an auxiliary fan and I have yet to see the needle creep past twelve o'clock, even stuck in traffic in 80+ degree weather.

[shagrath]

I just use it cause it's free!

[MarkD in NJ]

Lately I've been using BMW blue coolant and I've found that it seems to leak past hose connections a little easier than Prestone or other green stuff. Could just be my preception...

I've spoken to a few trusted BMW techs, shop managers and independant mechanics and they all recommend, due to the corosive properties of coolant in general, using as little coolant as possible to keep the car from freezing in the specific area of the country where you live. In my [heated] garage kept 533i daily driver, use 60% distilled water / 40% BMW coolant in NJ. My E30 318is which lives outside also has 60/40 and has never frozen that I know of.

Mark

[shagrath]

I have heard that 75/25 was good enough as well. I could be full of it though... or the guy who told me that is.

[rodpaine]

John,
I like the stuff you may be using in your other German Marque (the Merc). I started using it years ago because Euro Motors was close to my business in Bethesda and the parts guy there gave me a big price break. I now get it from Steve. My cooling system is as clean as can be, after all these years, but always changed every two years. I can't say the same for the truck after all its two year changes of the Prestone green stuff, which has left an oily, goopy build-up in the water passages.
FWIW,
-Rod

[Mike W.]

I've spoken to a few trusted BMW techs, shop managers and independant mechanics and they all recommend, due to the corosive properties of coolant in general, using as little coolant as possible to keep the car from freezing in the specific area of the country where you live. In my [heated] garage kept 533i daily driver, use 60% distilled water / 40% BMW coolant in NJ. My E30 318is which lives outside also has 60/40 and has never frozen that I know of.

Wow, I've never heard that, more like the opposite. Plain water is corrosive, anti freeze has additives in it to prevent that. On the other hand, plain water transfers heat better, and in older BMW's such as E3 and E12, 1/3 anti freeze and 2/3 water was the reccomendation.

I've not noticed a difference between different brands, cooling wise, except for I think it was Sierra, which was a propolyne (sp) glycol, instead of ethylene glycol. That's the "non toxic" stuff. I could never get an answer out of them about it, but several years ago I did from Prestone, which indicated it, the non toxic stuff, didn't cool as well, nor did it biodegrade as well as the regular stuff. But you could drink it. Didn't seem like a good trade off as it's not really my beverage of choice.

[John in VA]

Thanks for the replies. I was concerned about the quote in the original post, and wondered if anyone had heard anything similar. I guess it all works, with an occasional change.
I meant to check at NAPA for the G-05 stuff (or the SAAB dealer's stuff) when I first heard that was the place to get it, but opted for the BMW stuff "because it was there."
I see pre-mixed Prestone presently advertised as compatible with all/any color coolants. I used if for 20 years in the 2002 without trouble, but am a convert.

[wkohler]

I have been using prestone for years and years and years no issues. I am too lazy to mix antifreeze / coolant so I spend the 15 bucks and buy a gallon of 50/50. And I fulsh my coolant every 2 years or so except on my newer vehicles that came factory with the orange coolant that lasts 5 years

The cooling system holds a little over 3 gallons of coolant, so $45 for run-of-the mill coolant watered down with municipal water system water. At full price, BMW coolant is $26 a gallon. Buy two gallons of that and two gallons of $.79 Distilled water and you're set.

E21s with the M10 hold 2 gallons. That's easy-peasy.