Greetings Bill and Scott and everyone else,

First, to answer Bill's question. Prestone does make an orange antifreeze called 5/150 extended life that contains no phosphates,nitrites,silicates,borates or amines. This antifreeze says it's formulated for use in all cars and light duty trucks containing aluminum or brass radiators, even those using modine solder. The radiator in my car I can say with most certainty is made from brass or a copper composite, at least the interior tubing is. The cooling fins are probably a aluminum composite of some type.
I don't care to enter into a debate with anyone on what type of anything to use on their Benz, personally I could care less if some folks out there want to run straight hard water through their system. I think each person feels comfortable using whatever they were either taught to use by let's say their Dad or shop foreman or maybe even a neighbor that had good luck with something that they had used. If you want to make an informed decision use Scott's time consuming research and use what the book recomends, doesn't require a brain surgeon for that one, just someone that can read their manual. As far as water that gets mixed with your antifreeze, I'm a stickler on that one. Just travel across the States a few times and you'll find water that's so hard that you can almost see the rocks hitting the bottom of your glass. Phosphates are primarily used in antifreeze to soften the water for the folks out there just running the tap to meet the 50/50 or 70/30 mix to fill their radiator. Why do you think they put them in laundry detergent? It actually is suppose to hold hard water particles in suspension, but it does a poor job unless the company goes overboard on it's content, then you end up with the particles clumping together actually tearing your clothes apart as it's being scrubbed by them. So Scott, you're right about that one. Over time hard water mixed with antifreeze will cause the hard particles to drop out and form on cooling parts. The most common parts are those made from aluminum like radiator cores, if yours happens to be aluminum, return elbows (we all get that one), pump fins and heads if you also have an aluminum head. Heat and coolant level also plays an important roll on how fast these hard particles will attach themselves to these parts. If you're running low on antifreeze and the mix wasn't right to start with, you go into an overheat condition where hard particles will attach themselves to aluminum surfaces, like a welding affect. Also a neglected system that has gone several years without service has lost it's inhibitors and becomes acidic and basically the hard particles are now attached almost permanently to your aluminum parts, time to bring out the CLR to clear the passages. Engine wise, I can't say I've seen any gas engines that I've torn down look bad internally, but have seen all the attaching coolant items ate away at because of owner or coolant neglect.
For those Benz owners I'd say, If you don't want to use MB antifreeze in your engines cooling system, better know what parts are made of on your engine and cooling system , and where you can expect damage, if any to occur. The last note I would like to add is also the frequency at which you drive your car and the distances it travels when you do get behind the wheel. Like everything else on these or any other cars, short trips cause more harm than good. If your Benz is used like mine on a daily basis, commute to work and back with a daily average of 90 miles, then you get all fluids to operating temps and keep them there for a duration. If your trips are a few miles a day, I'd take the other car to work, simply because a diesel in particular was never designed for stop and go driving, but economy and warm running fluids and long hauls.

Charles

[Edited by can-do on 06-10-2001 at 01:34 AM]