Engine coolant drain plug gasket?
 

I recently changed the radiador, water pump, and hoses on my 82 300d Turbo. When I drained the block, I did not notice a copper washer on the drain plug. Since it is designed exactly like the oil drain plug except that it is larger, and due to the fact that it is leaking slightly, I assume it is supposed to have one. I cannot find one on fast lane, or other parts suppliers on the web. Since I have fresh MB orange in the cooling system, I would rather have the washer in hand when I pull the plug again. Does anyone know the size of the washer if there is one, or where I can find one. Thanks.

I think this uses a conical pipe seal. You may want to put some hylamar sealant on it and screw it in. If it isn't leaking, don't worry.

The plug looks exactly like the oil drain plug, except for the size. It has a 19mm head. It is leaking. If by "conical pipe seal", but if you mean the threads on the plug taper like plumbing pipe, this is not the case. It looks like its designed to take a copper washer. I could make one if I knew the size. Anyone?

On both my 4.5 and 560 the block drains have copper washers. Don't know the size though. You could always put the car on ramp, drain the coolant into a clean bucket, and take the plug to the store to fit an appropriate sized washer. Then re-use you new coolant from the clean bucket.

Think I found it, part number 07-11-9-963-200

sainttammany,

This problem occurs because the mechanic is unaware there is a washer there. When the plug is removed the washer initially sticks to the block. As the coolant gushes out it frees the washer and deposits it in the container the coolant is being collected in, where it is subsequently dumped. Then the "where is the seal" questions arise.

I think a quick call to your nearest Mercedes-Benz dealer should solve the problem. He should also be able to get you a seal for a quarter or two. Good Luck, and I hope this helps, Jim