The Stovebolt Site Forums The Shop Area Engine Shop draining block completely

Along with everything else we have been doing to the 235/1956 3100 we will need to take the heater core out for a leak fix. We would like to replace the anti-freeze with Evans coolant. The block must be completely drained. I was told that you can remove all the hoses and the thermostat and wrap a rag around an air hose and force air into the block from the thermostat housing to force all the coolant and water out.....??? Since we can't get the block drain plug out and do not want to break it off is this other method an option ? Thanks Steve

Forget blowing it out with air.Only the low point block drain will get the liquid from the lower water jacket.
Or you might turn the engine upside-down!!!

Too good to be true....OK, plan B What's plan B? IF.. we did manage to get the drain plug out would that accomplish a complete drain out? Steve

Curious... is the block drain plug the one that's on the right (intake exhaust) side of the engine in the very back by the bellhousing?

Thats it. You may want to stick a wire coathanger up there to see if any sediment is blocking the passage.

Heh, I was just wondering what that was. Mine was pretty well blocked with all kinds of sediment. The end of my plug was severely rusted because the previous owner only used water. Was pretty rough getting it out.

Who, have you tried penetrating oil to get it out? Or maybe the heat up to quick cool method? The only other option besides that plug I can think of would be like enginenut said, turning it upside down.

[quote=VanattiWorkshop] Mine was pretty well blocked with all kinds of sediment. Thquote]

You just hit the nail on the head as to the importance of removing this plug ANY time you "flush" the coolant. I'm sure many others have seen blocks with inches of crud in the rear lower water jacket.

As to removing this one, if you do round or brake the plug, it's not that hard to drill & tap 3/8 npt.

After you get the old plug out and a wire through the sediment, I'm not sure how you could remove it thouroughly without boiling the block. Try a pressure washer and direct it into the the drain.

I always replace with a bronze plug.

OK..I guess I'll give the drain plug another chance. I'll try PB blaster or Kroil. Vise grips did not budge it so I may use some heat. I'm afraid to twist the plug off as its in a tight place on the back forty. Would anyone go so far as to try a breaker bar or a long prize bar? How much torque can that little plug take??? Steve

If you've got an acetyline torch, heat the plug until it's red, and apply a wax candle or a block of parrafin sealing wax to it. Then just grab it with vise grips and turn it out. This procedure works even if you can't get it red. Use a Propane torch and get it as hot as possible, then apply the parrafin. Don't worry about melting or cracking the block- - -the heat conducts away from the plug in a hurry.
Jerry

Yeah, I think I heated mine with a torch to get it, I can't remember.

I'd think it can take a cheater bar worth of torque since it's a 3/8 NPT. If it's severely rusted on the inside though, it might shear off very easily. On my complete tear down, half my body bolts sheared off at the head even from just elbow torque because of the rust.

As BC59 said, you COULD always drill it and re-tap or try an EasyOut. Problem with easy outs is if you snap em off you're in a world of hurt.

The heat up method is nice because it expands the bolt, crushing the rust in the threads, and then you cool it and it shrinks back, helping get the rust unattached.



All in all, you've got different methods to try, but if the engine is still on the frame, I'd suggest working on that drain plug. I'd try a few soaks of PB or Kroil followed by light pressure on a cheater bar. If that doesn't work, try the blow torch and wax method. If that all fails, drill the dang thing.

All great ideas, my uncle used the wax torch method many times. The 235 is still in the truck so flame combined with oil and crud may not be a good idea??? I once saw a magazine article that took ATF and something else to make a break free product that worked better than store bought PB or Kroil....I cant remember what the other ingredient was, if anyone knows let us know and we will brew up a batch and give that a shot. It might also help someone else with same problem. I know you guys have secret formulas so help us out with the ingredients. Thanks. Steve

The formula for break-free was 50/50 ATF and Diesel this was supposed to out preformed any store bought product. It was tested in a magazine article I have been told....thought I would pass it on. I'll give it a try with my new Irwin stripped bolt head removers. I have never tried this type of bolt remover, they look wicked..Steve

Huh, I'll have to give that a try sometime. I've heard of guys adding ATF to diesel engines to help bring life to bogged down engines.

I've recently read of an acetone / ATF mix that's supposedly great as a penetrating oil like PB, so you might even want to give that a try. Seems like it would be real bad for a paint job either way though, so you might want to stick with something store bought if you're trying to keep a pristine paint job.

A small propane torch would be easy to handle, have a wet rag handy and just heat the end of the plug. All the grease and oil near it will melt off with out much fire or drama. Snuff out any big flames and continue to heat the plug. Heat & wax will work better then any oil mixture you can spray at it every time!

Joe

Nah...the block is pretty bare. Sounds like acetone would make a great carrier as it "creeps" real well.

Another question: We have a friend that has some truck ramps that lives a ways away. Would putting the truck on said ramps make removal of the drain plug easier by working from under the truck? Thanks Steve

The block drain is about halfway between the cylinder head and the oil pan, so working from the bottom might help a little, not much. I'd suggest using spray brake cleaner or carb cleaner on the block around the plug, olus a wire brush to get any oil/grease residue out of the way, then heat it up as hot as you can get it with a Propane torch. If you have access to a MAPP gas torch, it will get a LOT hotter than Propane. I have done refrigeration system silver soldering with MAPP, something I can't do with regular Propane.
Jerry

Yep....MAPP would be hotter. The last plant making MAPP has closed down. I'm glad I stockpiled a few bottles. I think I'll power wash the block area then hit it with MAPP. I'm just afraid that as per usual I'll apply too much torque while swearing and bust it off. Thus creating a bigger problem a.k.a. Murphy s Law. I think I'll talk myself out of doing it. Thanks Steve

Once you do the heat/parrafin trick, you'll be surprised at how easily the plug comes out. A gentle twist is usually all it takes.
Jerry

Jerry....I'll let you know. My uncle swore by this method so I'm going to try. Man, I wish he was here! Steve

We have another question: What is the drain plug suppose to look like? The PO buggered this one up so it looks like some kind of a bolt head??? Its not square? Is the correct thread National Pipe Thread 1/2 or 3/8 inch and what threads per inch? We made need to purchase a tap after pulling this thing out. NPT is a tapered thread as it is used for liquid....If we get this thing out I will replace it with brass or SS.Thanks Steve

I have the same petcock on my block as I installed on my radiator.

I have mostly used the drain plugs on the v8's which are 1/4 NPT.
I don't remember any older domestic automobile engines that are different.
Most originals have a hex head and are very soft.Drill it in center and work up toward the tap drill size and it will respond well.

Ditto on the radiator petcock. The block thread is 1/4" NPT, and so is the petcock.
Jerry

Thanks guys...did a 1956 235 come with a petcock originally? NPT 1/4 inch that sounds good should be an easy tap to get if we need it. Do these pet cocks have a habit of rusting out? They seem fragile. Maybe that's what happen to ours? What about a brass or ss plug with square head with some Permetex non-Harding seal goop...? Thanks Steve