I've got a '96 E320, bought new, now at 52k miles. I've been on a 2 year coolant flush, replacement cycle -- always done by a great Mercedes Benz dealership in Arlington, VA - American Service Center. Recently retired, I moved to Venice, Florida (in Sarasota County - just south of the City of Sarasota) and found that the local dealership suggested I replace "cracked" lower control arm bushings and replace "worn" brake pads and rotors. I carefully inspected these parts and also got a second technical opinion ... There were no cracks in the control arm bushings and the brake pads and rotors are good for another 15,000 miles -- I had just replaced them about 18 months back at around 35,000 miles.

So .... , I found a local mercedes benz (master) technician not associated with the dealership ... I asked him to flush and replace the coolant. He went ahead and replaced the the thermostat and housig o-ring. He showed me the radiator outgoing fluid and it was clear, with no particles in the fluid. He repeated same with the engine block outgoing coolant. He suggested we just do a dump and refill and not flush. We used MB Coolant and distilled water. I was a bit perplexed at not recommending a flush - heck we were there .. why not? ... but I went ahead given his experience and I didn't want to sour the relationship from the start. I know he is a thorough guy and not lazy. Finding a good MB tech who will work for $40 on the side ... is a rare thing.

Should the system have been flushed eventhough the outgoing coolant was clear and there were no signs of visible particles? Why wouldn't you flush the system??

I use Mercedes Benz coolant/anti-corrosive exclusively -- how often should I replae the coolant? Every two years? Three years? More? Thanks.

You live in Virginia, and if your state gets over 2" snow in winter you should follow the severe maintenance intervals in your owners book.
The suggestions about the repairs and services are the following.

Brake Pads: Pads should be replaced when the thicknes falls below 30% of a new pad thicknes, you should never wait 'till it is metal to metal since this will produce excessive heat that may damage your caliper seals and other expensive components. It is important to measure all 4 wheels for thickness, keep in mind that mercedes OEM rotor are composite material and cannot should not be machined, replacement is required with installation of new pads and sensors.(sensors should be replaced with the pads).

Coolant Flush: A coolanr flush is recommended every 30K to avoid corrossion of other build up inside the cooling system, this is preventive maintenance and is not required but will save you a lot of bucks on the long run. To perform a "Flush" you need an special(expensive) machine that a blue-lite tech may not have handy, that can be a good reaqson that he is recommending a drain and fill, instead of a flush. A flush will clean the inside of the angine, hea ter core and radiator, a drain and fill onli fills the raddiator and does not wahs and clean any additional components. A cleaning(flush) solutions is required in every flush.

Bushing: Bushingsd sre nade out of rubber and ruber has a short life, usually no longer that 5 years, if stress and dryrotting is becomming aparent , it is a lot cheaper to replace the bushing today and not an expensive contorl are sometime later.

Given your rigorous cooling system maintenance and use of MB (or Zerex G-05) antifreeze, a flush is not really necessary - just thorough draining, including the block. - open all the drain valves, let the coolant completely drain, close the valves and fill with a 50/50 mix of the correct antifreeze and distilled water. On my inline six both the block and radiator drain valves have nipples to attach drain hoses, so the job is easy and clean with no spills or mess. It's the easiest antifreeze change for any car I have ever owned.

I flush my system sometimes, but I'm not charging myself $80 an hour. If you're using a professional mechanic, the extra time/cost of flushing is probably not worth it if you change at MBs interval and use MB approved antifreeze. I have never removed the thermostat housing or changed the themostat. In fact, I have never changed a thermostat on any of my cars, and they range in age from 14 to 42 years (all bought new). Proper cooling system maintenance is good for the thermostat and there is no need to replace them unless they malfuntion, which is easy to diagnose.

Follow MBs recommended change interval listed in your owner's or maintenance manual. For my car it is three years.

Antifreeze corrosion inhibitor additives are depleted with time, whether the engine is operating or not, which is why it needs to be changed periodically, however, operating temperatures deplete the additives quicker, which is why some OEMs have a either/or time/mileage interval. In MBs case they just list a time interval, regardless of mileage - at least that's the case for my model. Given your low mileage accumulation, you would not exceed most manufacturers recommended mileage interval.

Be sure you also follow MBs brake fluid change interval, which is probably two years for your car (see owner's/maintenance booklets). This is especially important since you live in a damp climate. If you lived in Scottsdale, you could increase the brake fluid change interval to 3-4 years without consequence because of the dry, desert climate.

Duke

I change my fluid and hoses every 5 years on all my cars.

93 Ford Taurus 203,000 Miles. Never had a cooling sytem problem until 2 months ago when a PLASTIC side tank cracked.

92 Ford F-150. 165,000 miles. I did replace the water pump at about 125,000 miles and 12 years.

88 MB 560 SL, just got it and will put it on the same cooling sytem schedule.

Flushing. The only cars I have ever flushed are those that were completly neglected. Like when the coolent is brown.

John Roncallo

That's what the MY2004 service booklet says, and it applies to C, S, SLK, CLK, SL, and CL. Am I reading it wrong!?

I recall reading threads after threads in this forum to change coolant every 3 years. Why the newer models have jumped to such looooooooooong interval?

BTW, the same booklet does say change brake fluid every 2 years, which is same as advice in this forum.

The coolant service for my SL is every 3 years, per my manual and the dealer FSS. 15 years for coolant is asinine.

Coolant gets used up... additives get depleted... pH changes. If you wait until it looks like it needs replacing, you're too late, the damage has started.

I like to flush because I feel the turbulence will sweep up and carry away any contaminants, plus it gets all the old fluid out of there... kinda like letting oil drip out for another 15 mintes after draining the engine oil.

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95 E320 Cabriolet, 169K