Advice? 302 Expansion / Frost / Core Plug Replacement

[TeamPontiac79 12]

Hey all, I have 2 plugs leaking on the passenger side of my 302. Anyone have experience with whether it's possible to replace them with the engine still installed? I know I will have to temp support it and remove the motor mount, but wondering if it's possible to get leverage to install new ones? Alternatively, has anyone ever used the rubber compression style replacements? That's my second choice.

[MikeStang 247]

Dont think you can replace them in the car, at least I never could.

Rubber will hold but its a temp fix at best....I installed some rubber units back in the day, but they eventually blew out after some driving.

Just pop the motor out nad stick all new plugs in and be done with it.

[LoneWolf2U 136]

I have done both, Installing brass plug and rubber ones. It depends on how much trouble your willing to go through to do it.

Or as the case of the rubber plug install where it popped a plug on the road and its all that could be done at the time to continue on the trip.

Sold that car with it still in after 2 yrs.

[TeamPontiac79 12]

Mike, I wish I could just pop the engine out, but I'm at a severe disadvantage at the moment from a repair standpoint. I no longer own an engine hoist, and I only have a garage to work in for 2 days during after work hours. Can't afford to hire this one out cause I just got used and abused by a Mustang shop that didn't understand what "I have a budget, stop when you're getting near it and call me" meant, and sent me out with the plugs leaking and never said anything. Has anyone had any real problems with the rubber type? I do plan on pulling the engine at some point for a refresh, and can replace them then, but it's just not in the cards at the moment.

[1969_Mach1 333]

I've replaced many freeze plugs in various cars with the engine in the car.  But, without a freeze plug installation drivers it will be more difficult.  Sometimes I've used 1/2 inch drive extensions with a swivel at the freeze plug end and a socket that slips inside the freeze plug to get through different angles.  Because they are so difficult to get to and the odd angles you will have to drive them at, I think brass freeze plugs will get destroyed trying to drive them in.  I would go with steel, or try stainless steel.  Plus get the deep plugs, not the shallow plugs.

 

I installed rubber freeze plugs in the very first car I drove in high school.  It was a 1967 4-door Fairlane with a 289.  I don't like rubber freeze plugs.  But, they actually held for several years and were still in the motor when we sold the car.

[MikeStang 247]

If you can pull the manifold on that side and unbolt the motor mounts then put a block under the oil pan and jack the motor up on one side it will make it much easier for sure.

I would give the rubber plugs a shot

[Wycked69 20]

Considering your restrictions and time limit, I'd just slap some rubber plugs in it till you have the time and place down the road to pull the motor and put some brass or steel plugs in. I'm not a fan of the rubber plugs but they work in a pinch 

[TeamPontiac79 12]

Thanks for the replies folks. I very much agree with the negative sentiment towards the rubber plugs, but I think I'm going to go that route for now since that seems to be the general concensus. I don't want to take a chance pulling the manifold. Just about everything I've touched so far has had some level of failure, and I haven't the time for a can of worms right now. I'm pretty sure I can get the old ones out, and sneak the rubber ones in with just removing the motor mount and lifting the engine with a jack and block of wood as mentioned. I hate using temporary fixes, as they often become more permanent than not. I'm getting closer to having a proper work place though, and a strong desire to refresh the engine. Perhaps next winter it'll get done right!

[Ridge Runner 1,112]

If you can pull the manifold on that side and unbolt the motor mounts then put a block under the oil pan and jack the motor up on one side it will make it much easier for sure. I would give the rubber plugs a shot

I have replaced the freeze plugs exactly this way. Find a socket  that fits easily into the freeze plug but as close to the inside of the plug as possible ,use a long extension with a swivel and drive the new plug  in with a wooden mallet or hard plastic mallet .It is tricky to do but it can be done .Also use the deep brass plugs and seal them . If you have 2 leakers ,there will be more .

[Flanders 46]

i had two plugs that were visibly oozing coolant, but I figured I might as well replace all of them while I had the engine out.  As it turns out, *all* of my core plugs were rotten...but you couldn't tell from the outside.

 

I'm not sure how keen you are on replacing all of your core plugs at the moment, but keep in mind that the others may be on the verge of needing replacement too.

[Rsanter 152]

Some racers use one rubber freeze plug per side so they can easily drain the block. They rubber ones are good as long as you don't let them get old. If you have not pulled the engine in a couple of years to install brass freeze plugs then I would look at just putting another new rubber one in to be safe

 

Bob

[Dave R. 85]

Dorman makes expandable copper plugs.You use a wrench to expand them as you hold them in place. Using some 3M Super Weatherstrip adhesive on the edge of the plug before inserting the plug into the hole is helpful. Dorman offers those plugs in several sizes.  Good luck.   Dave R.

[TeamPontiac79 12]

I replaced the 2 leaking plugs, and 1 "extra" plug on the same side with rubber plugs. So far they seem to be working fine, but yeah, they don't give all too much confidence. I'm planning to pull the engine out hopefully next winter for a thorough cleaning, regasketing, painting, etc. I'll install all new brass plugs at that time. For now, I have the three extra rubber plugs just in case things get messy on the trip. Keeping my fingers crossed though!