124 Coolant flush
 

Hey guys,
I seem to have stumbled upon a great site.

My first question is, is there any write up on how to do a coolant flush on a 124?

I have performed various mechanical tasks on a few Japanese cars but yet have not done anything on the Mercedes. It seems that it is much more complicated and with less space to work with.

There is a block drain bolt on the passenger side of the engine block underneath the exhaust manifold. There is also a radiator drain at the lower left front of the radiator. Fill the system with either MBZ brand coolant or Zerex G05 if possible (both are a light yellow color).

Take off the upper radiator hose to fill up the engine block with coolant. Then re-attach the hose and fill the rest through the expansion tank. You can squeeze the upper radiator hose with the radiator cap off to "burp" the system. Fill up coolant to the seam in the expansion tank. Drive around a bit and run the heating full blast. Then re-check the coolant level and top off if necessary.

Very good write up!

Many modern cars turn into a PITA when flushing the cooling system, but these cars are very straight forward. Some of them have a small bolt on top of the thermostat housing that can be used to bleed the system upon initial fill in lieu of removing the upper hose.

Fan not coming on
 

I have an E220 coupe, and today I noticed that the fan would not come on.
There is only 1 fan in front of the radiator/air con condenser, and one which is behind it all and is ran off of the engine. The one off of the engine was on, but the one in front of the radiator did not go on at all.
I had A/C blasting, outside temp was 28 degrees C, engine temp would go up over the 80 mark and peaked a bit lower than the next line above 80.

What could be wrong?
What would I do to diagnose the issue?
When should the fan be going on?

Any help is greatly appreciated

Sorry that was meant to be a new post.

btw, my car is right hand drive, so when you say passenger side which side do you mean?

Your engine is supposed to run just over the 80C hash mark. The auxiliary fan (in front of radiator) will only kick on when your engine temperature goes slightly over the 100C hash mark (~105). The fan attached to the engine runs all the time (obviously)

Well thankfully they don't flip the engine from LHD > RHD. It will be on the "drivers" side for you. It's a 17mm bolt in the side of the engine block.

To get back to this...
I fill it with coolant through the radiator?
Also, I add coolant to the expansion tank?

Do I need to take the thermostat out?
Run the car with heater on?
Can I use radiator flush fluid?