changing coolant
 

I just bought a 89 300ce. Can anyone advise me how to change the coolant?

What about engine drain plugs?
 

I am ready to do the job as welll and have seen information regarding pulling the engine drain plugs. What about the drain plugs?

Thanks lino, it say in step 3...
 

It says in step 3 to remove crankcase drain plugs. I was hoping not to do so. Oh well, procedures are procedures.

By doing that, you will get most of the coolant out. Yesterday, when I did mine, I had to refill over 8 liters (more than 2 gallons). The radiator only holds maybe half of that.

Drain the block, otherwise you will either leave old coolant or flush in there, not desirable.

Use the citric acid, Preston isn't anywhere near as good at removing deposits. Not necessary unless you think you have considerable scale, though.

Peter

Lino
How can you drain the coolant from the engine block? If I remove crankcase drain plugs , all the coolant will leak out and mess up all the area in the driver side. (I saw a lot of parts in driver side under air filter case). Do I need a pump or tube go into engine block or just let the coolant pours out itself?
Thanks

The block drain valve is on the RH side of the block under the rear exhaust manifold. It has a nipple that you can attach a drain hose to - about 3/8". Makes it very easy to change coolant without spilling a drop.

I can reach the valve to loosen it from the front side using a crescent wrench. The radiator drain valve is behind the removeable cover on the RH side of the valence panel. It also has a nipple to attach a drain hose.

If you want to flush the system with water, remove the heater inlet hose from the back LH e of the engine and flush both the engine and heater circuit. You can do this mess free by rigging up some adaptors to your garden hose.

Changing coolant on M103 engines is the easilest and least messy of any car I have ever owned,

Duke

I'm about to do this job and need a little clarification on the size of hose needed to attach to the block drain fitting. Is it 3/8" OD or ID? Can the same hose be used on the radiator?

I have done this job without the hose and ended up with coolant running down into my armpits. Using the hose would sure be nice...

TIA

I realize that this is an older thread, but the Cooling System Flush reference sheet is no longer at that URL. If someone sill has it, I would appreciate it if you can post a new link to it or upload it here as an attachment.

Thanks.