On my 1965 F100, 352 I have a freeze plug (passenger side - behind the motor mount... of course!) that is weeping ever so slightly... a couple of drops over night. Can anyone tell me the least painful way to extract the old plug, and the best method replace it without pulling the engine (aviation permatex, RTV, etc.)? I know I'll have to support the engine to remove the motor mount, but will I need to pull the exhaust manifold?

Or... what about adding a stop-leak like alumaseal? What other havoc does that wreak on the rest of the cooling system? Does it work?

Lastly, if I replace the plug, it sounds like there is a steel or brass option. Is one better or last longer or easier to install?

Sorry for all of the basic questions -- I've restored cars all my life - but all air cooled so this liquid cooling thing is a bit of a mystery! But I must admit I LOVE working on this truck!! Thanks for all your help!

 

Leak stop gupe will fix a small problem temporarily, but usually contributes to several near future small problems or a big problem. Another thing to consider is that if one plug is leaking the rest will likely follow. Both of the trucks we have had neglected cooling systems and leaking and pitted freeze plugs; anti-freeze is not forever, although by some peeps idea of service, you wouldn't know it. I rebuilt both engines so no big deal. I prefer the brass plugs b/c brass is softer thus seals better and is less prone to corrosive damage. If you want to try a cheap fix and the plug is leaking b/c of pitting try to fill the plug cavity with a good quality epoxy - POR-15 has a product I have used for emergencies which will cure on an active and wet leak (not a gusher, but will fix a seep).

 

I've used the expandable rubber plugs a few times in areas where its to hard to get into to beat in a regular plug. I had a few in for years without a problem, they also do well at sealing if the surface is perfect. I'm not sure if the stud from one of these will clear the motor mount?

 

Gavin is correct when one is going the others are not to far behind. To do it right pull the engine and replace them all. I replaced mine on my 223 this year. I had to pull one back out as it was leaking with a new plug in. Best advice, clean, clean, clean, the bore needs to be spotless or you will have a leak. Aviation gasket sealer is what it used in the bore and on the plug prior to installation. I decent socket and a big hammer and it should be good to go.

 

Same problem (heck, I think it was the same plug as yours!). I used Alumaseal that comes in the little plastic vial. Do NOT use the Barr's Leak stuff; that is what can clog heater cores and so forth...best left to a real big problem. The Alumaseal has worked and I've not had drippage for probably 2 years now. I know I'm buying time, but without pulling the engine out or removing the front clip there just isn't access to do the job right. I swear by Alumaseal; it's worked on every little problem I've had except one BMW radiator (aluminum with plastic tanks). I love the stuff and always keep a vial on hand.

 

You could put a Bandaid on it, or you could just fix it. Those fast fix products are not worth using, as they will all plug your radiator at some point. They are OK for short term, but may end up causing more problems than they are worth.

The brass plugs are the best route, as they dont rust. If its behind the engine mount, you have 2 options. You can pull the engine and replace them all easily. This depends largely if you have the cherry picker and an area where you can do it. Once they are out, do them all, and check to see if anything else needs work while its out like exhaust manifold gaskets, etc. May not even be a bad time to clean the engine and shoot a coat of paint on it.

The second option and its probably not going to be easy, but its probably easier than pulling the engine if you dont have the tools and area to work on it, is to support the engine from the bottom with blocking and or a jack. Remove the engine mount. Remove engine stand if needed. The engine stand and mount on the other side, in combination with the blocking, will keep the engine in place while you work on it. Now replace all the freeze plugs on that side of the motor and reassemble.

I have always put my freeze plugs in with a little RTV sealant on the edge of the plug, but I know a few guys who swear by just putting them in dry. They are an interference fit piece, so they are tight. Just be sure the area where the plug sits is nice and clean either way you do it. I drive mine in with a seal driver, but a large socket or a piece of pipe will work as well. You just need to be sure you are driving as far out to the edge as possible to avoid bending them. I have seen guys pop a freeze plug because they thought that a hammer in the center would be a good way to install them. What they did was cup them, and they didnt seal properly.

Best of luck!

 

wow.. great information... thank you. one more question... what is the easiest way to remove the old plugs?

 

A hammer and a combination of chisel, pry bar, screwdriver, ViseGrips, pliers, etc. I hit them on the edge to turn them slightly, then pull them with a Vise Grips.

 

ok thank you, makes sense. any particular supplier better than others for the new plugs, or any auto parts store?

 

Anywhere you can get them. Buy however many you want to replace, and some hi-temp RTV.

 

perfect... thanks for the help!