HarleyW72

Hello all, I am experiencing some unknown things with my 2000 clk320. I had to replace the radiator due to a leak and I also replaced the expansion cap with a new one. I added about 2.5 gallons of 50/50 mix G-05 coolant as recommended. I can let the car sit and idle for "x" amount of time and the coolant hoses never seem to get any pressure built up in them.. The car has hot heat and never goes above 80-85C. Does the vehicle have to be driven to pressurize the system or am I missing something.. There are no leaks as my expansion tank is full and there are no signs anywhere of any liquid.

HarleyW72

CLOSED- Figured out for myself

burgca

Glad you solved your problem, but what was the solution to your issue?

HarleyW72

I had some air in the system but I don't understand how since my expansion tank is the highest part of the system, I assumed all air would have made its way to there. It still has some weird issues such as running a higher temp now with the new radiator and the duo valve constantly clicks but the air and heat seem to be working okay. There are so many things on these cars its like working on a spaceship lol.

Serndipity

Couple of suggestions.

1. Before opening the radiator drain plug, turn on the heat to maximum and warm up the engine (e.g. opens up the thermostat, fully drains the entire system, preventing air pockets upon refill).

2. Remove the expansion tank cap (e.g. breaks the sealed system vacuum, promoting full system drainage).

3. Loosen the radiator drain plug and drain the old coolant.

Note: No need to remove the drain bolt on the block (e.g. nothing more will come out).

Hint: Suggest installing a new radiator drain plug (e.g. better safe than sorry as old plastic / O rings deteriorate).

http://www.autohausaz.com/search/pro...20Drain%20Plug

4. Close the radiator drain plug and refill with 50/50 mix of Zerex G-05 and distilled water.

5. Before you reinstall the expansion tank cap, run engine until hot air comes out of the heating vents and the upper radiator hose is becomes hot (e.g. bleeds out any air that may have entered the system when refilling).

6. If required, top off the expansion tank level and reinstall the cap.

BTW.......Because it's so easy and inexpensive to do (e.g. a gallon of Concentrated G-05 and distilled water is about $15), I drain/refill every other year, which works out to be every 10,000 miles. IMHO cheap insurance.

HarleyW72

Hello Serndipity, thanks for the response but all above procedures were completed with the exception of a new radiator plug as I installed a new radiator due to leaking. And as I mentioned in my first post I did use G-05 with a 50/50 mix of distilled water. I have heat and AC just found it odd it was running at a higher temp than before, perhaps the system wasnt pressurizing properly due to the cooling system leak. From what I have researched close to/at the 100C mark is considered normal but I wasn't sure. Thanks and take care !

Serndipity

HaeleyW72 Even though no one initially replied to your post, thank you for all the follow ups and as a result, your thread will helpful to other W208 owners.

I believe you're all set at this point.

FYI, I've enclosed a thumbnail that explains the W208 cooling system. Note, how the thermostat modulates the system temperature, from being fully closed to open.

Basically, normal operation, varies between 80 C to 100C, which depends on numerous factors (e.g. outside air temperature, which may be seasonal , as well as driving conditions such as open road or stalled in traffic).

Lastly, in regard to hearing your duo-valve clicking, can't comment, because I have a cabriolet and I changed HVAC system, from running in 'automatic' to 'manual' mode.

Basically, because I live in New England and even thought the 'in car' temperature sensor is turned off by the power roof controller, this affords me the ability to control the AC or heating as required, to enjoy top down driving, every day, for at least 6 months / year.

HarleyW72

Serndipity I appreciate all the help, you and other members have provided a lot of valuable information over the course of the last year and I don't think I could have figured out a lot of issues on my car without the forum.. And thank you for the very helpful detailed diagram !