w126 300sel coolant engine block drain plug
 

1988 300sel

Need to drain the old coolant from the engine block but i can't find the drain plug.

Is the drain bolt/plug on the driver or passenger side?

What size bolt?

Any advice is greatly appreciated

Passenger side, on the block below sparkplug #5. I don't remember the size, it's a bolt with a nipple sticking out of the middle. Mine was pretty tight.

https://scontent-iad3-1.xx.fbcdn.net...7f&oe=5ACEAEDC

Fitts, Thanks. Will drain tomorrow

19 mm. Slip a hose on it to control where the coolant goes to avoid a mess.

After draining, take it out and clean the threads and then put anti-seize on it before re-installing.

Would this be the M103 engine .Or m104 ?. I have the M103 and I see no drain plug .

I believe the m103 and m104 shared the same block, the difference was in the cylinder head and injection system.
You should have a drain in that location.

I found the drain plug and drained the remaining coolant from the engine block. I refilled and bled the air out. Took the car for a drive and for the first time on 2 years I was able to drive without heat blowing towards my face. It almost seems that the heater core flushing help dislodge a lot of gunk that was preventing the system to work properly. Now I have heat when I want heat. I have a brand new heater control valve that I will be installing this weekend. After that, I will be driving the car to an AC shop to see if they can charge the system properly.

Did you do a citrus flush?

citrus flush
 

No, I did not use any type of citrus flush. Thought about it but opted to flush using regular water from garden hose then followed by using Zerex G05 with distilled water to push out the regular water. I think I will flush again right before summer of next year and will use a citrus flush. Have no idea how to use such flush. Any harm to engine, hoses, seals or other components when using the citrus flush?

Thanks for the info Fitts07 ..
..