Hello everyone wondering if anyone has ever installed freeze plugs on a 62 cadillac 390 engine? I need to replace the center freeze plug on the driver's side. I wanted to know if there's a way to replace it without removing the engine? Can i just remove the exhaust that goes attached to the manifold? I forgot the name of it that goes on the sides.. can't remember right now. i think that's what it's called. Hmm.. any tips would be greatly be appreciated. My brother wanted to remove the motor mount to install it but wondering if there's an easier way.
Murphy's Law... the least accessible freeze plug will be the one to leak. If all you need to do is pull a motor mount, then do it. But be advised, you have one leaker, the others may not be far behind.
Within the year you will have a couple more. Check each one with a screw driver they may be real thin. I usually stick the new one in the freezer to get it just a bit smaller and if you lift the engine and pull the manifold there should be enough room. Don't be surprised if the engine has more than one.
I don't have a 390 but I had rusted-on header bolts. I wouldn't touch rusted header bolts again unless my engine was pulled and I was doing it for a rebuild. Trying to drill out broken header bolts on a bolted in engines a nightmare.
Pretty sure yours would be the same as the 1960 390, I changed a bunch of freeze plugs on one and never had to remove the engine. If you have to remove the exhaust manifold to get to one, it shouldn't be a real tough job- get the manifold hot, then have at the bolts. Replace the manifold gaskets, and stick some anti-seize on the bolts on the way back in. I remember vaguely having to make a tool to sit in the freeze plug so I could whack it in with the hammer. (piece of dowel , cut to about 3/4").
Snapon and maybe Matco makes a tool for installing freeze plugs that may help. It is a punch about 2' long with a round swivel on the end. You place the freeze plug in the hole and drive it in from an angle where you have room.
Any time I need to replace a soft plug in the car and its the one behind everything I have always used a rubber expand plug.
Yep, that is what I did on my 54 Fleetwood many years ago. I still would check the rest of them too. If they can be replaced easily, then do it!
What do you mean by a "soft plug"? Brass?- and what are these " rubber expand plugs" of which you speak?
I've had one of those rubber, expanding plugs blow out of a small-block Ford. Wouldn't trust them for anything but temporary usage.
Some people say soft plugs some say core plugs some say freeze plugs. They actually are not a 'freeze plug" by design, they have to do with the pour of the cast iron. I think the name soft plug came about because brass was normal 50 or 60 years ago. Probably the best most proper name for them is core plugs. Anyway there you have it. Rubber expando plugs can be found at any auto supply or hardware store or plumbing supply. I imagine that they were originally plumbing parts. What they are is a rubber (neoprene or urethane) plug the correct size to slip in with a washer on both sides and a stud and nut which you tighten up. When you tighten the nut it squashes the plug out to make it a tight fit. I have never had one fail yet (knock on wood) but anything can fail.
I have the Snap-On version of the freeze plug installer tool. It works pretty well. I have been installing brass plugs whenever I have one fail or rebuild an engine. I have had good success with them lasting the steel ones seem to rust prematurely anymore.
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