Rounded Engine Coolant Drain Plug - W202 M122

[thephatmaster]

Hi there,

I have an old '99 C200 I saved from being scrap metal with copious amounts of welding.

M111 engine despite this threads title (which I can't edit)

It's not a tidy car, but it's been reliable and gets serviced accordingly.

Just finished a service today (with the car fully warmed up to try and combat the arctic temperatures) and remembered that the coolant drain plug on the engine block was a pig last time. As expected it was pretty chewed up, but I was keen to do a proper job.

Well one long lever and a lot of swearing later and the plug is now very chewed up.

I didn't even get it fully open before I relised it was a lost cause, and I was better tightening it again. I only hope its tight enough not to leak.

Got about 6 or so litres of coolant out of the rad drain plug, so wasn't a total lost cause.

Now I wonder what the community's view on what should be done next (or next coolant change) with this very inaccessible plug.

(1) properly attack (with heat / hopes / prayers / brute force) the plug in an attempt to replace it; or

(2) learn lesson - it's a 20 year old car - leave the plug the heck alone.

Discuss!

 

[91dm]

If it doesn't leak, leave alone!

With my last 202 I focused on what broke first rather than creating issues!!

 

[optimusprime]

Mine is 32 years old and i could not even get at my drain plug. So took it to the garage and asked them to remove it part way, and then screw back in place so it would make it easy for me to undo it . Garage refused to open it up ..He said last one he did on an old car the plug came out along with the threads ,after that i left it in place ..So went through a full coolant flush without openiong the drain tap up . Then i draind all clear water off after back flushing for 30 mins .Fitted every hose back in place , and filled up with 50% antifreeze and then toped up it up with water ,. Warm up the engine to get air out Any problems with a weak mixture later on i top up with neat concentrate . I use a antifreeze check tool on the coolant in the catch tank .