M37 rusty water jacket- Advice?

[Ferroequinologist]

Hello fellas,
I have a question. My wife recently re-bought my former M37B1 (interesting story) and she is rebuilding it, with my help.

Last night we pulled off the hoses and water pump, so that we could have the radiator boiled out. Well, it seems that at some point in its life, it just sat with water in the engine. The inside of every pipe is corroded and the water pump was full of rust chunks, so bad that I could tell by the pump where the water level had been for quite some time.

I haven't ran across the need to flush a block so badly rusted before. Anyone have any suggestions? maybe a mild acid bath? Or a high pressure water flush? or a total rebuild is the only way to go?

The engine runs like a clock but now I know why there were 'hot spots' on the side of the block. I mean, some passageways were totally plugged.

We are trying to get it servicably by the VA rally but definitly by the GA rally.

Any help or hints?

 

[asgtoolman]

I don't have an answer to you rust problem, but am anxiously awaiting the interesting story about the repurchase.
Take care of your immediate problem and post the story when time permits.

 

[Bill W]

Flushing and then back flushing the block through the water pump openings with a garden hose should remove quite a bite of the (loose) scale.
What kind of shape was the water distribution tube in?

 

[Ferroequinologist]

Which tube is the water distribution tube? I don't have my manual CD here at home or I would look it up myself.

The water pump bypass was totally clogged, from the pump back to the thermostat housing.

 

[Bill W]

This is the distribution tube ( ORD part # 7351075 )
It slides into the block via the discharge side of the cooling port ( where the waterpump bolts up to ) and it prevents hotspots by distributing the water/coolant more evenly. When you mentioned hotspots this was the first thing that popped into my mind

 

[runk]

With old British cars, we have mixed some of the rust / scale cleaner products (I think a brand is CLR ?) into the water and let it soak a bit. Helps loosen more of the rust and crud. Make sure all the metals it will contact are compatible !

 

[Ferroequinologist]

Thanks Bill, I'll go out and try to pull it now.

runk, good idea, I'll go look at a bottle and see if it will eat through anything in short order.

 

[TIGERFANS2]

I know nothing about M37's but have some limited (as in still have my original '69 model) experience with wives and I humbly suggest you hang on to yours.

 

[M-37Bruce]

Quick Question

Hey Bill,
Should the radiator be removed for the distribution tube removal/install?

 

[jimk]

I had a similar problem on vehicle to left. I did what Bill just said (flush with garden hose) using the strong Prestone suff from the auto store. Repeated it maybe 2 or 3 times till it water ran clear. I let it run with the hoses off and garden hose in block. Gave CLR some thought but passed. If you use it don't let it stay in there too long (like overnight). It attacks aluminum, copper and brass if left in too long. Took the radiator to a shop and the soaked it in boiling caustic soda/acid. It cost a lot. Both tanks leaked after that. I ended up taking both tanks off. One side still had few handfuls of rubbery crap trapped inside.

I added a coolant filter when done. Big bits will clog the coolant filter inlet fitting.

I had a radiator shop use compressed air w/water on a clogged auto radiator once. The system he used must have had an accumulator. It was quite dramatic and loosened a lot of scale. Made the radiator change shape. Cost was low.

 

[Maverick1701]

I ran CLR through my first deuce (and my old ford diesel) when I bought it....you should have seen the crap it pushed out. Like Jik said...dont leave it in there too long.

i ran 20mins w/CLR, flushed w/h20 then ran CLR again for another 20mins before refilling w/antifreeze. It worked quite well...no leaks (knock on wood lol)

 

[zak]

Yes Bruce you need to remove the radiator. The last one I removed took two days! I have to soak it with blaster and use a slide hammer. If you want to be somewhat through remove the welch plugs and use a coat hanger to loosen up the crud. Short of boiling out the block its the best you can do with the engine in frame.

 

[MitchG]

Ferro the other posts are correct on having to pull the rad to get the tube out. It's too long to come out other wise. I used a smaller diameter piece of round stock with a hook bent in the end. Slip it into the tube and hook it into one of the slots in the tube. I then clamped some visegrips on the outer part of the stock and tapped that with a hammer to get the tube loose. You should also look at pulling the block drain when you start flushing. That is if you are just going to run water thru to flush out the big stuff before running it with CLR or some such cleaner in it. A pressure washer will give you more ummph for the initial cleaning but it's messy!!!
If the tube in the block is trashed John over at Midwest Military has new one's for sale. I also picked one up a while back from somewhere out west(The name escapes me right now). I'll see if I can dig up the name for you if you decide you need a new tube.

 

[Bill W]

Hey Bill,
Should the radiator be removed for the distribution tube removal/install?

Yes you do being the tube is about 23" long

 

[Ferroequinologist]

Well, I got the tube out without pulling the radiator! there wasn't much left to it, and I got about 8in out and broke it off, then pulled about another 8in, etc. So I will need a new tube. We still have to pull the radiator for a flushing anyway. Man, I need to find mine/buy a new cable for my camera!

 

[MitchG]

Hey Ferro I have the tube out of one of the engines I have at home you can have if you want it. It's used of course but it's really solid and not filled with gunk. Just let me know.

 

[Ferroequinologist]

Hey Mitch, that's great! I'm sure Angie will want to come look your trucks over again in the daylight for more goodies too.

 

[MitchG]

Sounds good man!! Consider it yours!! Just let me know when you want it or want to come look for some more goodies!!!

 

[m376x6]

Some thoughts to consider. If your block and radiator are this bad, your freeze plugs are also leaking or about to. They are not that difficult to remove and reinstall. I would remove them and then proceed to to flush and use air pressure to blow out the chunks and antifreeze that has turned to a brown/black paste. Once you have most of the worst stuff out re-install new plugs and use either caustic or CLR to finish the rest of it. Is Red Devil drain cleaner still available. Thsi was the best as it had no metal shavings like Draino.

 

[M-37Bruce]

Red Devil makes TSP also.