318 expansion plug leaking

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BJammin

BJammin

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Ive got a 73 Scamp 318 v8 and ive Been noticing coolant leaking onto my headers. Found the left middle engine expansion plug to be leaking and have slight movement. Is there any tips for installing a new one with the engine in the car. I know i will have to remove the header and possibly the steering gear. Any tips will help.
 
Can you sneak say a 3/8 rod in there between the pipes? Doorman used to make a tool I could loan you since I have one.
 
Buy a rubber Expansion plug, and tighten it up. A 1/2" wrench and your done. the next time you have the eng out, clean and install a new brass freeze plug.
 
Cudafever said:
Buy a rubber Expansion plug, and tighten it up. A 1/2" wrench and your done. the next time you have the eng out, clean and install a new brass freeze plug.
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I used one of these back in the late 70's on the back of my 318's head. Drove it for a couple of years with no problem. I didn't even know they were still making them!
 
halifaxhops said:
Can you sneak say a 3/8 rod in there between the pipes? Doorman used to make a tool I could loan you since I have one.
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I have the headers all wrapped up. Wont be able to get anything through there. Either way the header will have to be removed. The space is really tight. Just would like to know if anyone has had luck with installing in car. The expandable plug is an option for now. Im getting married this September and this it's our wedding car.
 
If one is leaking chances are the others aren't far behind,sorry to say. Are yours steel? If so, use one of those small extendable magnets and stick to the opposite end your going to tap so you don't lose it down in the block and use a pair of pliers to pull it out,you can tap the new one in with a socket but make sure you put some gasket sealer around the edge.
 
Sedanman.
I'm figuring as much with the others not being far behind. I will try to install a new plug this weekend with some sealer. And check the others while there. Anyone know the diameter of the plug?
 
There's a brass plug with a closed nut in the center that you tighten to expand the plug. These have worked very well for me over the years.
 
Why not pull the engine and get it done, its a weekend job or 1 day depending on how you work and how many times you've done it. Think about the time you will spend playing around trying to make a tool to get at it, you could play around for a few hours and get nowhere, when you could have the engine out on a stand in the same amount of time. Also as mentioned, the "temporary" screw type plugs also work when you don't have the time to pull the engine. In the case that the car is your only daily driver the screw type repair may be the way to go.
 
I ordered the set of brass expansion plugs and a rubber plug. Going to try the rubber seal plug for now to hopefully get my through my wedding. Have the whole interior to get done. After the wedding will be pullingbthe engine to either build or find a 360 motor to build then swap.
 
I am skeptical on quick fixes being aan Automotive Mechanic and knowing the chance you take. But with money and a time crunch. Also renting am appartment currently and dont have room to pull the engine. Im going to try to take the chance. Thanks for all the advice.
 
Dorman has a whole drawer full of these at independent parts stores. If its behind the header, you can usually just loosen the header and get enough room to get back in there and remove it. The rubber expansion plugs literally slide in and then just take a 1/2 box end to tighten. they sit flush minus the nut. 1 5/8 size
 
You're only 30 minutes from me. If you can't get it let me know. If you drive it over I can pull the motor, replace them all, and have it back installed in a day.
 
BJammin said:
Ive got a 73 Scamp 318 v8 and ive Been noticing coolant leaking onto my headers. Found the left middle engine expansion plug to be leaking and have slight movement. Is there any tips for installing a new one with the engine in the car. I know i will have to remove the header and possibly the steering gear. Any tips will help.
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Yes, recently.
Took the exhaust off the block, took the motor mounts off the block and leaned it over for one side then the other way for the other side.
Took probably 2 hours and it was a PIA. :D

Especially since some of the centers popped through and left the outer ring of the plug in the block, and probably what some of yours are going to do.

I used a 36" steel rod that I ground a concave in the end with sharp edges to get the ring out, and that worked fine.
 
i used O E M brand master freeze plug installer tool to replace freeze plugs on side of block eith motor in car hardest part was getting old plug out. use indian head sealer on new plug works great, good luck
 
Remember there are two in the back, between the engine and trans.

Also there are two depths of brass plugs. The deeper ones tend to go in straighter and are less likely to pop back out.
 
The rear plugs, the plugs behind the accessories, the ones in the back of the heads... that's why you pull the engine and do them all at once. I like the deeper brass ones.
 
Use Permatex #1 (also known as Aviation Form-a-Gasket) for a sealer on these, not RTV. This is made for direct metal to metal sealing with tight fitting parts.
 
Spent the day changing some sensors. Installed the rubber plug and flushed the whole cooling System. She's up and running b with no leaks. Now for some nice weekend days so i can start the interior work for the carpet. Thanks for all the tips. Was able to loosen the headers and get my hands in there. If any more decide to go I'm pulling the engine and building it up a little before it goes back in.
 
When installing the metal cup plugs, you are supposed to get the edge of the cup just past/below the chamfer in the hole for best sealing.
 
And the dish plug behind the camshaft: lay it in there dish out and put a 1/2 deep socket on its middle, then smack it hard. The dish will bend in and expand the OD a few thou in the process, sealing it. I replaced a freeze plug with a steel replacement (sunday afternoon job, no time for brass order) but I painted the back with ultra copper RTV prior to installing it. Filled the block the next morning and the darn thing looked new 5 years later when I rebuilt it. The others were close to rust through
 
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