Ok, I'm new to the forum, so Hi, everybody. I've got a 1976 F100, 2WD, with a 390 in it. Some aftermarket stuff, Edelbrock intake/carb, headers, etc., but nothing major.

I just finished replacing the head gaskets. The reason I did this is that it blew all the coolant out the back of the engine between the head and the block. So, after a bunch of work, I have new head gaskets and it isn't spewing antifreeze.

After finishing this, I'm in the cautious observation phase, checking to make sure everything is working OK, nothing crazy going on, setting the timing, etc. Everything seems OK. I let the engine run for a good half-hour or more on a few different occaisions throughout the day as part of this process; I don't want to get stuck across town with something failing, as this is the first time I've ever done head gaskets.

Anyhow, I notice coolant dripping underneath the truck. Not a fast drip, and nothing like the full-blown evacuation of coolant from before, but definitely a steady drip. At first I'm thinking maybe it's just been pooled up somewhere and is being blown out by vibration and the fan, but it isn't stopping. So I start poking around underneath there and I finally see it's slowly coming out of one of the freeze plugs. This is frustrating, as I just spent two weeks doing major surgery on the engine.

So now I have another coolant leak, although this one is at least slower (for the moment). My question is, Can I replace the plug with the engine in the truck? What would a mechanic charge me, on average? I can see it from underneath, although it's behind the header it's between two of the pipes, but there's still a lot of stuff to work around under there (I think, I'm not positive, that it's on the #3 cylinder. I would have to double-check this, so don't hold me to it). Are there certain kinds of freeze plugs available that will be easier to install in tight spaces? What is the process like? Is this something the amatuer mechanic should even attempt? I've had a whole bunch of things go wrong all at once, some small, some big, and I'm getting very annoyed. At this point there's a big part of me that wants to just forget it all and buy a moped.

Thanks for your input. Aaron.

 

You can go to the local parts store and get either a steel or brass freeze plug (just make sure you save the old one if that is possible so that they know what size to give you). 2.- Some parts store sell expandable freeze plugs that are rubber and have a washer on each side of the rubber plug with a bolt in the middle (this maybe the easiest fix). 3. You can also buy an engine block heater from the parts store and install it and then you could plug the engine in when it is cold out (if you don't already have a plugin, if you do then you would have 2 and could plug both of them in and this would produce enough heat in the block to actually move the temp gauge (mechanical gauge anyway) from what I have seen. Take a drift and try to get the plug to partially come out and then grab it with a pair of pliers and do one of the above that I suggested. Just make sure after you get the old one removed to take some Emery cloth and clean up the core plug hole (high or rough spot, rust) and then take some carb cleaner spray on a rag and wipe the sealing surface off a few times. If you go the route of another steel or brass core plug then coat a fair amount of (where it seal to the block) High-Tack to help it seal and ease installation. Drive it in with a socket that is a tad smaller than the plug (don't use a socket that fits real snug!) Drive the plug in with taps from a hammer until it is either flush with the block or just slightly deeper than the block surface.
If you go the route of an expandable freeze plug or a block heater then follow the above cleaning procedure and then either use Sil-Glyde or some wheel bearing grease on the rubber plug (expandable plug) and/or the O-ring seal on the block heater and torque the nut or bolt to what the instructions say. Not sure on the expandable core plug but on the 3 Kat's engine block heaters that I have installed in my FE's the torque spec is 14 to 19 INCH pounds... not foot pounds.
Your going to probably have to remove the header to do a new brass/steel freeze plug. Might be able to leave it on with the expandable or block heater idea.
P.S. The brass freeze plugs are better than the steel because they don't rust.

 

Well, it shouldn't be hard to look and see if you can drive in hard freeze plug with the engine in the bay. My experience says "no." You need considerable room and a mandrel of some sort, also room to swing the hammer.

The Neoprene expandable plug is the best bet here. Get the right size, and follow the instructions which say "NO sealer" and "NO grease." Just push it in, tighten the bolt and you're done.

Plan to replace this plug once a year from this point, as they will degrade and blow out. Been there, done that.

 

You can also get a brass/copper expanding plug that may last longer than the rubber plug.

 

Just don't get to frustrated and buy a ricer or a chevy.