freeze plug / coolant leak question 72 dart 318

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moparjon

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ok found coolant leak this morning . 72 dart 318 . it is weeping from the back freeze plug passenger side top , at the firewall . i have never dealt with freeze plugs before . how do you get them in and out ? can i get this one out and new one in without taking the motor out ? from the top looks like a tight area to work with , but looks like from underneath , the trans filler tube is in the way a little . do these come out easily ? and maybe i can take off the oil filter to get more room to work . would changing freeze plugs likely fix the leak ? or , will i have to help seal it with something around the freeze plug ? also , what kind should i get and where from ? would one of those "HELP" ones from auto parts place be good enough ? what about silver seal / stop leak just to get by for awhile ? over 234,000 miles daily driver , so just trying to fix leak without pulling motor . any suggestions appreciated . thanks !
 
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I'll guess that the plug is rusted through after so many years so stop leak may not help. And besides, if the rad has any near-clgos in the tubes, they can clog closed with stop-leak. It won't be too easy; you have to get some working room. I would be pulling the trans tube and fitler and trying, but I'd be ready to detach the exhaust and remove the exhaust manifold. You can drill through them and then thread a lag bolt in for a puller. Or you can tap on one edge into the block and flip it sideways and them pull it out with pliers. But if you do that, be careful not to tap it into the water jacket and lose it inside. There are probably some other tricks that others can mention.

Reinstalling takes some room to be able to start it in straight and then tap it down. Dorman PilotSeal types are easier to start in straight. One alternative is a copper type expansion plug; Dorman used to make them in a few sizes.

See here on page 3: https://www.dormanproducts.com/catalog/hardware2006/127-130_Sec8_Part1.pdf

The rubber expansion types get used but I am personally leery of them.
 
There are various mechanical plugs, IE they don't drive in, they "wrench" in. If you have the room you can use them, assuming you can get the old one out. "The thing is" some of the rest might be right behind.

I was ENRAGED, in the early 70's freshened up a 440 and put into my 426 64 Dodge. Gave the 440 heads to the shop told them to tear them down, check, hot tank, do whatever for a valve job and REPLACE THE FREEZE PLUGS

They came back all nice and PAINTED even. So I put em on and ran it about two weeks. YUP. Rear plug right against the firewall!!!
 
I have used the rubber expansion plugs many times and never had a problem with them. You can also use a block heater if you need it.
 
These kind, as well

core_plug2.jpg
 
I have used different length bolts/nuts/spacers, and using the firewall as the "base", then push/"press" the rear head plugs in.
 
The original owner of my car knew he had a small leak in the radiator. He had installed what I call a "weak system" radiator cap ( 7 lbs ) . He had also added Barsleak from time to time over several years. That worked. I drove the car home ( 2854 miles ) without a problem.
First order of business was a new radiator and proper 18 lbs cap, and recovery reservoir.
About 6 months later I found one plug leaking behind the starter. See how system pressure reveals weak points ?
I went under, dropped the starter, poked a screw driver through that plug and peeled it out. Then I very easily poked that screw driver through the nearest plug forward. I knew they were all the same age, same rusted, sooo, I replaced every plug I could access short of pulling the engine. Yes the passengers side plugs were just as weak.
I flushed and flushed, cleaned large chunks of barleak out too. I know I'll need to pull the engine someday but... over 7 years now with no recurrence. Good luck to both of us.
 
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