Advice for replacing freeze plug behind injector pump (W123)
 

I've been working on a 85 300D that sat for a decade for the last 3 months. When I bought it, I quickly discovered a freeze plug had come off under the turbo. I took the turbo and both manifolds off the car and cleaned all of it up and replace all the freeze plugs on that side.

Today I was doing final assembly and was excited to finally see the car run when I had a major setback.

I was flushing the cooling system in preparation for new coolant, when to my horror, I discovered the freeze plug behind the injection pump had also come off.

I see no other way to replace this thing without taking off the injection pump and oil filter housing.... which also means buying all new seals and gaskets... which means the car will be in my garage for the foreseeable future.

Any suggestions on the best way to proceed?

Here are some photos of my turbo and manifold restore that I am finishing up

That's what I would do. Take both of those items off, do all the plugs on that side and reseal the IP and oil filter housing. Eventually, one or both of them will leak on you, so might as well replace the gaskets with MB gaskets while you are in there. Also a good time to R&R the oil cooler lines. Looks like you are in Dallas, so look up a place called Hose Fast I had them rebuild a set for one of my cars a few years ago. I think it was about $60 out the door.

There is a tool that has an angled steel rod with a disc mounted on a ball and socket swivel that is used for installing Core/Freeze plugs. It allows you go get around some obstructions.

I have never used one so I don't know if it would be suitable in your case.

Thanks everyone for the input

Was there any antifreeze in the engine?