mercedes coolant

[lou552]

can any one tell me what color mercedes coolant is and how it should appear in the coolant reservoir. i have a 1999 c280 with 52,000 miles on it, no problems, but went to local (nonmercedes) gas station for annual inspection and was told that i need cooling system service and that dealer who has performed all service on vehicle since day1 has damaged system. i can't get a service appointment with dealer today, labor day weekend, but need to take a long trip this evening. and don't want to get taken for unnecessary work. looking for peace of mind. thank you

[mercedessd]

can any one tell me what color mercedes coolant is and how it should appear in the coolant reservoir. i have a 1999 c280 with 52,000 miles on it, no problems, but went to local (nonmercedes) gas station for annual inspection and was told that i need cooling system service and that dealer who has performed all service on vehicle since day1 has damaged system. i can't get a service appointment with dealer today, labor day weekend, but need to take a long trip this evening. and don't want to get taken for unnecessary work. looking for peace of mind. thank you

it is light amber in color and to the untrained (local gas station) eye will look clear like water when looked at in the reservoir, we have had many customers at our specialty mercedes shop return with similar tales as yours complaining that we used water only, you have to use the coolant tester to see what the coolant condition is. those guys are used to seing green or other colored coolant, have them use the hydrometer if they have one to see what condition is. it will tell the freeze/boiling point. if you do need a flush be sure to use mercedes coolant.

[sprintuser]

I find it hard to add anything to mercedessd's wonderfully detailed comment. I had recently changed the coolant in my w140. When you combine 30/70 (MB coolant/distilleddistilled water), the mixture looks almost clear like water.

I second the notion of using a hydrometer (they are under $5 at Walmart or parts stores, a cheap insurance for your peace of mind before the long LD trip). Plus, the meters are marked to show the percentage of coolant vs water.

IF you do need to change the coolant, its a breeze to do. You simply undo the drain plug (which is mostly on the driver's side, bottom of the radiator) collect the fluid in a container (and properly dispose it off). I would certainly flush the system with distilled water (fill the radiator, run the car to operating temp to open the thermostat and then drain again, a couple of times till you get clear fluid during flush). Then fill the radiator with a 30/70 mixture of MB coolant and distilled water, check with hydrometer and drive away!

Have a safe trip!

[lou552]

thank you both ..advice was much appreciated

[Scott Singer]

also do a search on refractometers for gauging coolant quality a neat high quality way to diagnose coolant.