My coolant light came on , last time I put in a 50/50 , but my mechanic said not to do that that MB needs special kind ? Or he said to just put in water if it comes on again. The light has come back on , do I put distilled water ? Or just regular water ???

 

The optimum ratio for coolant is a 50:50 mix for the best corrosion protection and boil-over protection. Anything from 45:55 to 55:45 is considered okay. MB does not recommend DI water unless your local tap water is really hard or acidic but most owners seem to favor it anyway.

But, step one is finding why you are losing coolant. A small leak may not show as a wet spot on the ground if it is evaporating as soon as it leaves the system. If I had to repeatedly add I would use the proper 50:50 mix to maintain the correct ratio. If it was once in a blue moon I would just add a little water.

You don't say but if you have E320 with the V6 you should flush the coolant system and replace with new every 3 years according to MB.

Hope this helps some. Good luck.

 

hi planetobagirl ,

I have to agreed with what RichardM98 said, but if there is no leaks on ure coolant, then it should be the coolant level sensor need to be replaced -but most important you need to check out is there any signs of coolant leaks.

good luck & share us your info on your mb repairs!


p/s: RichardM98 -a very good explanation! keep it up dude!

rockerfella174
brunei darussalam

 

The sensor is a good point although the OP's original posts seem to indicate that they had added water previously.

The procedure for manually checking the coolant level is not well documented outside of the WIS.

Here is a brief description:

When the engine is cold, place a folded rag/towel on the cap of the expansion tank and turn slowly counter-clockwise until you feel it release. If there is a sound wait until any pressure is the system is released. Continue to turn in counter-clockwise until the cap can be removed.

Look straight down into the opening. If the level is correct, you should see a small (1/4"x1/2") plastic tab just at the liquid level. It is located just off center at the 9 o'clock position assuming you are standing at the side of the car. If the level is low it will be easy to see. As necessary add coolant until the tab is just covered.

After a couple of drive cycles, check the level again (when cold). If the level has dropped add coolant again to the tab. To ensure that no air was in the system, drive a couple of more times and recheck, if the level has dropped you have a leak. If it has not, then have the sensor checked.

Good luck.