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Bi-metal engines & coolants

Started by thysonsacclaim, 06 February 2011, 12:58 AM

John Hubertz

Quote from: WGB on 06 February 2011, 06:53 AM
And I imagine there is some zinc in all the alloy castings as well plus the brass/copper in the heater core.

I am looking through the maintenance schedule for my E500 and the coolant is apparently only scheduled to be changed every 15 years.


That is amazing (the 15 year interval).  I must admit I've not read the coolant schedule of my manual on my '99 C280.....   What year is your E500?
John Hubertz
"When the going gets weird, the weird turn pro."
(Hunter S. Thompson) 

1977 450SEL (Max Headroom)
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2010 W212 E500 (E550 in the US)

Here is page 2 of the seven page US maintenance schedule for the M272 (E350) and M273 (E550)



That is quite impressive. I'd like to know what they put in that stuff (although I'm sure longevity is also in part due to the engineering, too).


QuoteStill, oils aint oils and you'd think a low vicosity suitable oil with good heat transfer charcteristics could be developed for the conditions of an engine's cooling system.

There's new exotic (and old) chemicals which could work a lot better. Liquids themselves tend to be weird, though. There's Newtonian (like water) and non-Newtonian (like cornstarch water slurry) and they act differently in viscosity of course and heat transfer, conductivity, density, etc.

Water and ethylene glycol are so plentiful, though. You can, to a degree, adjust for the shortfalls of water by whatever you're adding to it (silicates, etc) to reduce conductivity, elevate boiling point, etc.

I did find two neat things regarding this:

Not sure if the Rotella stuff meets the specs, though. I'd have to look into it more before sticking it in the car. The hoses would undoubtedly be fine.


Quote from: WGB on 07 February 2011, 03:44 AM
Quote from: Carl Jones on 07 February 2011, 03:20 AM
Curious, what's the advantage of the MB coolant?  Surely the blue colour or the green colour is simply a dye?

I don't know what the advantage in the colour is but M-B provided an amber coolant for more than two decades which I last saw used in a 2002 ML270CDI we purchsed new. Accoprding to "Mercedes Enthusiast" magazine some years ago the amber coolant was phased out because it caused the aluminium radators to slowly silt up which actually did happen to me during my ownership of a 1987 126 300SE in 1990 or thereabouts.

In the later 90's and obviously ongoing until after 2002 the coolant in the new cars was gradually replaced with the blue coloured coolant and at the same time the top of the plastic coolant reservoir changed from clear to black. My 2003 W211 E320 had the black topped reservoir filled with blue coolant.

Apparently the blue coolant is not considered compatible with the amber and careful flushing must be done if changed over.

Anyway the blue is teh only genuine coolant available now afaik.

Green - wouldn't have a clue if it is any good. My car came full of green and the first thing I did was drain it, flush several times with distilled water and fill it with genuine M-B blue and distilled water 50:50.


I guess it is kind of like gasoline. Gasoline is actually odorless. The distributors opted to add odor so that it would be easy to detect. With all the things that we put in the vehicle I suppose it is important to know which is which.