Hello,

Mine is a 2002 c320.

What is the method to drian coolant from the rad? I noticed a small red plastic knob on the bottom drivers side of the rad. Is this the drain plug/screw?

I also noticed that removing the thermostat will likely cause a quantity of coolant to flow down the front of the engine. Any harm in letting this happen? I guess I could come up with some sort of diverting contraption, but it wouldn't catch all of the fluid.

Last, I got antifreeze from my local mb dealer. It's a yellow/orange color and the coolant in the car is a green color. Any problems here? MB has always done the serice and flush prior to the warranty expiring.

Thanks,
Brian

that red knob looking is the drain for the radiator. There is no problem with letting the fluid coming out after the thermostat is removed. Just catch it all with a large pan underneath. Factory fill is Hepu green in the car but the stuff at the dealer is yellow/orange. THere is no problem with mixing those. Since you are replacing the thermostat, you'll be removing most of the fluid anyway.

Thanks.

Is there a bleed for purging air after refill?

Brian

I just did this job on an M112. I did not drain the radiator because the coolant was flushed less than a year ago.

I ended up losing 3 quarts of coolant. For purging, just park the car with the front higher than the rear, open the cap, start the engine, then squeeze the up radiator hose a few tims when the engine warms up. Realy no big deal. You could also fill it, drive for a day, and check for level.

Thanks guys. Done deal. No problems.

Brian