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Dex-cool issue

I recently posted about a change to Havoline Dex-cool. Since then, I've run into this article:

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SO... I'll be going back to the green after a complete flush. I had read quite a bit about silicates and phosphates eating the aluminum cooling system of the older BMWs and it appeared this was a solution. Apparrently it may not be the best solution. When I replaced my water pump in April 2005, I noticed some corrosion under the hoses at the thermostat housing. The aluminum was being eaten! Since I had recently bought the car, I was doing maintenance as things happened instead of all at once. Pelican discusses the topic here:
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Not being an engineer (kudos to those that are!), all the information I found wasn't specific... just saying "use this coolant." A "WHY" would have been good. So, older and newer BMWs have slightly different cooling systems, between the aluminum and plastic parts. My '86 535i has an aluminum vice aluminum/plastic radiator. It's practically new looking despite its age and the aforementioned thermostat housing.

I don't recommend the Dex-cool, despite the "no this, no that". I'm doing the green in a 60/40-ish mix with distilled water like I used for the last

15 years in my other BMWs. It gets changed every 2-3 years with 3-4 month checks on the system anyway. All this was necessary because I never saw anything DEFINITIVE on the issue. Learn from my mistake (no damage!).

Fred - no harm, no foul. Here is my correction.

Bill '86 535i

Reply to
Bill
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Good deal Bill. But why would you now select the green stuff?

Do a little more research on the topic (my bad experiences with green stuff is limited to SAABs, not Bimmers) and I think you will find that your best bet would be to try and stick with the manufacturers specified G-48. I know it's inconvenient to find (I buy mine from a SAAB parts place online for $12 w/ free shipping), but the next best stuff is the G-05 which you can buy at AutoZone in the Zerex G-05.

Reply to
Fred W

In Mercedes circles green = evil and is enough to make most people say "pass" when finding this in a potential car purchase. You use the golden MB coolant, period.

MB says NOT to use distilled water. This makes no sense to me; I email MB Canada and they didn't understand it either and said it was fine. MB Germany recommends "tap water" which is a bit idiotic. In parts of SF and some suburbs of Toronto the water is so soft it may as well be distilled. Where I live the well water is basically liquid rock. It's not like all "tap water" is created equal.

MB Coolant is $12/gal from the dealer and isn't like anything else. It's buffered more strongly than anything else to prevent corrosion of aluminum and is plastic safe, MB rads have had plastic necks since 79.

Reply to
Richard Sexton

A small amount of trace minerals is desirable in cooling systems. Just the amount left when you backflush the system is enough though, refill with 50/50 distilled water and [antifreeze of choice]

Reply to
Rex B

Actually, I believe the MB coolant is Glysantin G-05, which you can buy a lot of places.

Reply to
Fred W

Bill, one other thing. You said 60/40 do you mean 60% water or 60% antifreeze? The reason I ask is, even though 60% antifreeze can be run it isn't recomended unless you expect to encounter major low temps (like in Alaska or something) as the cooling capaboility of the mizture will not be as efficient.

50/50 is good enough for most people and if you live down south where cold is 30-40 degrees, 60% water is OK.
Reply to
Fred W

Bill, one other thing. You said 60/40 do you mean 60% water or 60% antifreeze? The reason I ask is, even though 60% antifreeze can be run it isn't recomended unless you expect to encounter major low temps (like in Alaska or something) as the cooling capaboility of the mizture will not be as efficient.

50/50 is good enough for most people and if you live down south where cold is 30-40 degrees, 60% water is OK.

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-Fred W

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I have always run between 60/40 and 50/50 antifreeze/water. I don't really know why other than possibly getting the coolant to run a little cooler (mostly my flawed thinking? LOL). This way when I topped up, I could use water. This helped me use all the coolant so I don't have any left over laying around. I never buy pre-mix because they charge as much and I like mixing my own. I was considering Water Wetter when I lived in Biloxi, MS on the Gulf of Mexico. I was alsways hot and humid and made my car run a little warmer than I liked. I moved to Omaha, NE this past Feb because of Katrina. The weather in Omaha is noticeably warmer than 12 years ago when I was here last.

Too bad we can't just run straight tap or distilled water! Hahahahah!

Bill in Omaha '86 535i

Reply to
Bill

You sure? I'd love to have an authoritative reference for this.

Reply to
Richard Sexton

No. Unfortunately, I'm not positive. Maybe someone on the MB list would know for sure.

Reply to
Fred W

In Canada and the US, both BMW and Mercedes coolant are made by Valvoline. BMW, and SAAB, uses Valvoline Zerex G-48; Mercedes uses Valvoline Zerex G-05:

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I use SAAB "Blue" in my BMW!

Reply to
bfd

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