Little help: flushing coolant / engine block...

[crimsonaudio]

Engine's been running a bit warm, intermittently, so I decided to redo the cooling system - new thermostat, water pump, radiator, all new coolant. Removed everything but the water pump so far, got a few gallons of coolant out, finally flushed (I think) the engine out running water through it via a hose.

At this point I've removed both the water temp gauge sensor and the block drain plug, fully expecting them to be clogged, and boy are they - I've dug out about 3 inches of what looks like dried carbon gunk, still haven't gotten a drop of anything out of the block drain (I actually think I've dug in far enough I'm hitting the inside wall of the water channel on the other side - feels like I'm up against metal now).

Now I think I've probably flushed everything out of it as I've run water through via the heater core inlet as well as the water pump and the thermostat housing until it runs through clear, but I'm a little concerned that even now I'm getting nothing from the block drain plug. I want to ensure I'm getting coolant to the back of the engine, is there anything I can do?

Any help appreciated.

 

[Steamer]

You might wanna pull some freeze plugs for a good look in there if your digging out that much junk. The dried carbon crud might be that aluminum leak stop stuff. Mine was nasty & I had to take radical measures to clean it out. Detailed in this thread.

https://forum.ih8mud.com/40-55-series-tech/565208-radiator-rust-water.html

 

[1973barnfind]

I pulled the small plug on the bottom of the block (header side about between 5th and 6th piston) and dumped all the fluid when I got the cruiser.
luckily it was green-ish after sitting for so long. I put in radiator flush, ran the engine, then ran the engine with a hose into the radiator, with the bolt out. flushed out everything. I then put in bargain coolant, distilled water, and a coolant additive.
I live in florida heat, and have never had it peak 190 degrees F. even when in low range in mud, revving the heck out of it.

 

[crimsonaudio]

You might wanna pull some freeze plugs for a good look in there if your digging out that much junk. The dried carbon crud might be that aluminum leak stop stuff. Mine was nasty & I had to take radical measures to clean it out.

Yah, didn't really dig that much stuff out, just feel like I got as far as I can and still nothing coming out of the block. Wondering if I can somehow add a temporary fixture so I can generate enough water pressure to force the gunk out of the system...

Detailed in this thread.

https://forum.ih8mud.com/40-55-series-tech/565208-radiator-rust-water.html

Thanks for the link, reading now...

 

[crimsonaudio]

Hrrm, read the thread - gives me hope that I can fix this - thanks, Steamer!

One problem - I have no idea what the freeze plugs are...

You think running muriatic acid through the block as you did would do the trick? I really want it to be clean, if possible...

 

[Steamer]

Freeze plugs are thin walled metal plugs pressed into the block. The theory is that if the coolant freezes the expansion will push out a freeze plug rather than crack the block. There's four down the header side and about two inches in diam. The fouth one back is just above the drain plug.

 

[Steamer]

When I ran muriatic acid in there I had the water pump, thermostat, and the t-stat housing removed. I'd be afraid of straight muriatic acid on my pump or on aluminum.

 

[crimsonaudio]

Yah, I've pulled those as well as I'm replacing the thermostat and H20 pump - seems like that might be a good choice if I can't get the freeze plug out...

 

[Steamer]

Getting them out is easy. Puttem back in was always a hassle for me. Save that ole pump. The back plate can be removed from the pump and a hose fitting brazed in. Bolt it back on and ya got a good entry point for what ever flushing you do.

 

[4x4paper]

on those engine the last cylinder get the most crap. so you should take the last freeze plug close to the fire wall out and try aggressively to remove the gunk around with a coat hanger

 

[crimsonaudio]

Yah, now I just have to find the rear freeze plug - going to pull the carb and manifolds today (replacing the carb and intake manifold anyway) and see if I can actually see the rear plug...

 

[bsevans]

I use this setup with a water hose to power flush the head from the back of the engine with the bottom radiator hose and cap removed/disconnected. I use this after running a strong flushing agent that is compatible with the engine and radiator. I also remove the coolant plug in the block on the driver's side.

 

[crimsonaudio]

That's a great idea, bsevans - where'd you find that part?

 

[bsevans]

That's a great idea, bsevans - where'd you find that part?

I made it from a Russell AN tee. I turned the two legs to fit 5/8" heater hose with a lip so the hose could not slip off. You can find similar plastic ones made by Preston at most automotive parts stores.

 

[crimsonaudio]

Awesome, thanks.

 

[Steamer]

(I actually think I've dug in far enough I'm hitting the inside wall of the water channel on the other side - feels like I'm up against metal now).

You'll never know for sure unless you remove the freeze plug just above it and get your finger in there. I had to pound in a drift pin with a bfh to break into the water jacket.

just feel like I got as far as I can and still nothing coming out of the block.

If you did dig in far enough to hit the cylinder wall across from it, and still no drainage, then you're really clogged up in that area. I doubt you'll get it cleared with a traditional flush but worth a try. Good luck & keep us posted.

 

[crimsonaudio]

OK, just figured out my freeze plugs for the back end of the block are literally up against the firewall - I'm in no way qualified to pull the engine (experience or tools)...

Will a heavy flushing treatment have a chance of working through the crud in the back of the block or am I doomed? What are my options short of pulling the motor (which, again, is beyond my capabilities at this point)?

 

[Steamer]

I was speaking of the rear freeze plug on the manifold side of engine. I just realized I have four plugs down the side of my 74F but you have only two towards the center. Sorry for the mislead. As for flushing, it just depends on how bad & what type of gunk you got in there. On mine, the strongest flush I could find tripple dose with much less dilution then specified I got no results. It was the straight muriatic circulating for 20 minutes that did it.
Have you considered putting together the flush set up I described in the link above? I'd send ya mine but I sent it to CA years ago to someone on the CCOT forum (whole shebang pump & all) and that was the end of it. It worked like a champ.

 

[crimsonaudio]

Yah, Steamer, I think that's what I'll do - I don't have any welding gear here, but I can use hoses on the old water pump to make a closed loop with an impeller and straight muriatic acid. That should to do the trick - might take longer without access to the rear freeze plugs - if not I'll have to figure something else out...

 

[scoutin cruiser]

How did this turn out?