Guide to Replacing Freeze Plugs - PeachParts Mercedes-Benz Forum

2dieseljohn · #1 10-04-2008, 01:26 PM

As most of our freeze plugs are getting on in years (and to be honest we probably have not used the right coolant or done our flushes) I thought I would share my experience.
The 1st picture is the leak from the #2 plug on the Rt side of my 1979 SD (617). I took all stuff out of the way IE: air cleaner, turbo, manifold A search of the net lead me to the conclusion that if one was bad, soon the others would go. So i decided to replace all three. I ordered the part from the dealer and the plug was only $5.00 per. I ordered 4 as I thought I may screw one up( I did not)

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I assembled all the tools, emery cloth,brakleen and Permaflex 2 form-a-gasket.
Clean the area well so as not to get any gunk into the coolant passages when you knock out the old plugs.
I used a 1/2 punch and then a rolling head pry par worked well for the 1st two. Then I ran into a problem- My punch started to pushed the plug into the passage- I solved the problem by screwing a bolt into the plug to keep it from falling into the coolant passage and then I was able to use pliers to deform it and using the bolt to pull it out. Sounds simple but took an hour or so of careful trial and error. Next the installation...

2dieseljohn · #2 10-04-2008, 01:49 PM

Next it was time to clean again and then sand with the Emery cloth the inside of the plug hole. Sand only as you pull out as to keep passages clear.
I then cleaned the new plugs so the sealant would be sure and have the best chance of sticking.
Place a thin coating around the outside of the plug and the inside of the hole. allow to get tacky.
This next part was the best way I could come up with to "Tap" the plugs in - I used a 1/2" sliding T-bar with a 22mm socket and placed it into the plug and tapped into the hole. This part went very quickly.
The last picture is the old plug as you can see they were ready to replace.
Now to flush and use the proper coolant.
I hope this will help some of you in the future.
Regards

Matt L · #3 10-04-2008, 01:55 PM

I have also used Permatex #2 for freeze plugs and have never had a problem.

bgkast · #4 10-04-2008, 01:56 PM

Nice write up, thanks. It looks like your nice collection of tools came in handy!

TheDon · #5 10-04-2008, 01:58 PM

I've got a leaky freeze plug that is blocked by the injection pump and some electronic box on said pump... damn the 85's.

jt20 · #6 10-04-2008, 02:02 PM

nice mandrel.

is it difficult to get the plugs started in the hole (centering)?

and did you chrome your valve cover.. naughty.

2dieseljohn · #7 10-04-2008, 02:16 PM

Thanks all. The plug I placed in the hole with my fingers- then tapped into place. As for the valve cover , not chromed but polished. Buffing stuff is one of my hobbies

coonerboy · #8 10-04-2008, 04:49 PM

Looks like a good chance to install a block heater if you would need one!

2dieseljohn · #9 10-04-2008, 06:40 PM

Funny you should bring that up- I did try. Used a 24" breaker-bar with 3' cheater-pipe and..not a budge!! After doing a search found a few tales of cracked blocks. So, no Block heater. Oh well...

coonerboy · #10 10-04-2008, 06:56 PM

Quote:

Originally Posted by 2dieseljohn

Funny you should bring that up- I did try. Used a 24" breaker-bar with 3' cheater-pipe and..not a budge!! After doing a search found a few tales of cracked blocks. So, no Block heater. Oh well...

Good move. I've broken my share of bolts, studs, etc and its funny that after I've done that a few times I begin to second guess myself with how much torque i'm applying and the potential results if to much is applied. Its one thing to break off a bolt, its quite another to crack a block.

2dieseljohn · #11 10-04-2008, 07:25 PM

Yeah, I try to stop myself when I get a big cheater-bar or "Thundar" the 10lb hammer. Or a hacksaw.

Cr from Texas · #12 10-05-2008, 01:45 AM

Quote:

Originally Posted by TheDon

I've got a leaky freeze plug that is blocked by the injection pump and some electronic box on said pump... damn the 85's.

Mine are original, but I can see one down there behind the injection pump that would be hard to do. Don't all 617's have freeze plugs in that location? How many on each side of the block on a 617?

2dieseljohn · #13 10-05-2008, 09:30 AM

I'm not sure , but I think it is 3 per side. I could only see 1.5 but I was able to have my 11y/o son reach the last one and his arm came back with oil but no green. Taking off the Rt side was bad enough I hope the Lt side hold a few more years.
Regards