500E Coolant Loss

[Fangio]

In late April of this year, I had the coolant system in my 1992 500E flushed. At the end of Sept, my coolant light came on and I added 8 oz of Water Wetter, plus 16 oz of distilled water to fill up the reservoir.

I happened to check the reservoir this past weekend (2 months and maybe 1K miles later) and found it to be low again. This time, I added 32 oz of distilled water to top it off.

My question: should I consider this to be the coolant system "burping" (a total of 56 oz of liquid has been added since late Sept) or am I losing coolant?

I should also add that after I had this coolant flush in April, once the warmer months came along, I noticed my temp gauge going higher than it had in the past and actually had the fans kick on for the first time I can remember.

Any thoughts? Have I added too much H2O and now need to add coolant? What coolant can I use for the M119? Do I need to get it from the dealer or is there other stuff out there that is OK? Do I need to go back to the dealer and get this sorted out?

Kirk
1992 500E
Pearl black/gray
63K miles

[glenmore]

Coolant level is much like brake fluid level and not like oil level.

Any drop in the brake fluid level or the coolant level is an indication of a leak.

If you are a DIYer, you can rent for free a tester at your local Autozone, to pressurize your system and find any obvious leaks.

The leak could be in all sorts of places from the hoses to the water pump to your head gasket.

Or you might be able to locate the leak under your car just by looking for the telltale dried white chalky stains of leaking coolant.

glenmore
1991 300CE

[ke6dcj]

FWIW- a brake fluid drop is normal if it's very gradual, and your brake pads are getting worn.

My W124's with fresh pads will start at the max. brake fluid line, and when the front pads are 3/4 worn, it just barely above the minimum mark of the brake fluid resevoir.

If I don't change pads and continue to drive aggressively with only the minimum amount of brake fluid, the "Brake" light comes on intermittantly (same thing happens with the windshield washer resevoir).

:-) neil
1988 360TE AMG
1993 500E

[rjfjr1]

Radiator cap could be the culprit. Have system pressure tested and you may find a number of minor leaks due hoses that need to be replaced/tightened. Not to mention possible issue with water pump.

[Kestas]

After adding 56 oz. water you should start worrying about the coolant strength. Most auto supply places have inexpensive testers for coolant strength. You should buy one. I always top off fluid with a 50-50 mix of antifreeze and water.

[Fangio]

Thanks, guys, for the responses. What coolant should I use for this engine? The manual strictly forbids all coolant but M-B approved, but I am sure that is crap.

If the cap is leaking, would I see traces of coolant around it? How about if there is a head gasket leak? Traces in the tail pipe/white smoke?

Kirk

[ke6dcj]

Leaking cap: look for "white" deposits on the coolant tank.

Leaking head-gasket: look for oil in the coolant (check the coolant tank).

It might be easier to find the MB Coolant, but the Valvoline G-05 is MB approved (same stuff as MB Coolant) and my local Autozone carries it.

http://www.valvoline.com/pages/products/product_detail.asp?product=10

http://www.imcool.com/articles/antifreeze-coolant/G05-Glysantin.htm

:-) neil

[Kestas]

Ditto for the Zerex G-05 antifreeze. It's approved for MB engines and costs around $6 per gal vs $11 per gallon for dealer antifreeze. Judging from the formlation both should be compatible with each other.

Coolant loss due to head gasket leaks can show up a couple of different ways. It can leak into the combustion chamber where it is burned, resulting in white smoke from the tailpipe. Or it can leak into the oil where it can turn the oil into a milkshake color. The second scenario is more serious. I suppose it can also leak to the outside of the engine, where it can be diagnosed just like any other coolant leak where you look for white deposits.