The Stovebolt Site Forums The Shop Area Engine Shop rusty water in radiator

I've got a newly rebuilt 235, new water pump, and new radiator. About 15 miles on the engine. When I initially filled the radiator with water, then drained it, it came out rusty. I have filled and drained iht system three times, and it still looks like the coolant is brown/red sludge.
the engine over heats, and spits water out of the over flow hose. I just bought and installed a coolant recovery tank, and now it's full of sludge.
Any suggestions on cleaning this up? I can't believe how dirty this is after all the work.

Tim

Did the so-called "rebuilder" flush the water jacket thoroughly? That usually involves pulling all the core plugs out of the block and either pressure-washing the cooling system repeatedly, and/or doing a lot of probing around in the water jacket with a steel rod to dislodge the crud. Once it's reassembled and in the vehicle, the process is much harder. I've used a mixture of muriatic acid (technical-grade hydrochloric) and water at times to chemically clean a block, followed by a flush with a full box of baking soda dissolved in water to neutralize the acid. Run the engine for about 20-30 minutes with a cup of the acid used to clean masonry and a full fill of water, followed by the baking soda flush. Repeat as necessary until the flush water comers out clean.
Jerry

I don't really know what the machine shop did as far as cleaning the block. I do know that when I tore the engine down prior to sending it off to the machine shop it was absolutely full of rust. And when I did the rebuild I looked inside and it seemed to be clean. And after I mounted it on the frame and got the radiator hooked up I filled the radiator and pulled the drain plug at the rear of the engine and got good flow there. Also where the temp sender goes at the top of the block. And I filled/drained a few times before adding antifreeze.

I'll get some acid and give it a shot. Probably fill/drain several times. See if that clears things up. Part of the problem is that it sat for quite a while since the rebuild, like a few months. But it did have water/antifreeze mix in it.

Tim

HRL's recommendation is spot on but since the engine has been rebuilt and was clean at one point, you could try some over the counter engine flush and follow it's instructions. I used some Prestone flush on an engine that sat for approx 4 yrs and it cleaned it out pretty good.

When draining the engine, remove the block petcock instead of just opening it. If the water doesn't gush out you'll need to poke around in the hole with a metal coat hanger to loosen up the crud to get it to drain out. Poke around as deep into the block as you can go. Once it's gushing out it should turn clear by the time it's done.

I like to run 160 degree thermostats in my Stovebolt engines. In hot weather my old 216 and now my new 235 runs a steady 180 on the temp gauge and about 5-10 degrees cooler in cold weather. Even at that the heater will run me out of the truck if I don't crack a window.

Good luck
Dave

I know this may seem a little strange but it works well. I have used a concentrated toilet bowl cleaner. Drain the system and add a standard bottle of cleaner, refill and run untill the temperture comes up. Shut it down allow it to cool again (usually overnight) and run again untill the temp comes up. Allow it to cool again and flush with clean water, refill with coolant and you should be good to go. I have used this on several engines with great success, had to come up with something while deployed overseas and didn't have access to a standard coolant flush. It also leaves your engine smelling "Minty Fresh"

lol

If the engine is clean and doesn't have a lot of crud in it, you can buy a new aluminum radiator for less than the work on your present one will cost...sadly. I got one on Amazon for about $120 delivered and it cools like crazy. Good luck.

Another use for that toilet bowl cleaner- - - -it makes a great remover for gun bluing. When I'm getting ready to reblue a firearm, a soak in Sani-Flush removes the old bluing right down to bare steel. Then I do a detailed polish job and use a bluing solution that works with boiling water instead of the caustic salts method that takes thousands of dollars' worth of equipment and a separate room to do the procedure in!
Jerry

If the engine is clean and doesn't have a lot of crud in it, you may be able to buy a new aluminum radiator for less than the work on your present one will cost. I got one on Amazon for about $120 delivered and it cools like crazy. Good luck.

He has already replaced the radiator.

Well, I got out this morning to drain the cooling system so I could do the radiator flush. When I opened up the drain valve at the bottom of the radiator, all I got out was a slow drip of fluid. So I think the bottom of the radiator must have a bunch of crud in it. I'm going to try starting the engine and running it a bit to wee if that will help empty things faster.

There must have been a bunch of rust in the block for it to crud up so much and so fast. I'll probably do the flush process a couple of times and see what happens

Wish me luck

Like was said before, find a metal coat hangar and push in the drain port, with the valve removed, (two on a 503etc.) to make sure all debris is removed.

Ed

OK. I finally ended up removing the drain valve at the bottom of the radiator, and got a huge gush of water. Which looked remarkably clean. Turned out the drain valve was plugged up, maybe from a wash trying to build a nest? Once the radiator was drained I filled it with plain water, ran it for a while, then drained again and filled with water and radiator flush. After I drove it a short distance, about 3 miles, I just left it sit until tomorrow. Question is, if the water draining from the radiator looked so clean, can rust particles float on top of the water? So that the water I can see looks bad but overall is clean? When I ran the engine with plain water and no radiator cap I could see rusty particles on the top of the water.

Could it be that the cooling system is good, and that my overheating problems are due to timing?

Tomorrow I'm going to drain the system and refill with 50/50 water/antifreeze, then recheck the valve adjustment and timing. Then mess around with adjusting the carb again and see if that helps.

Tim

You need to drain the block too. On the drivers side back near the bell housing you'll see the petcock or where the petcock should be (if someone removed it and plugged it).
If when you open the petcock and it just dribbles out, remove the petcock and it should gush out. IF not, probe into the block with a metal coat hanger and probe around as deep as it'll go until it does gush out. It should carry the debris out with it.

The water jacket around cyl's 5 & 6 being lowest tend to collect the most crud. Sometimes enough to where the coolant can't encircle the cyl's enough to carry heat away.

I'd recommend draining from the block 1st so theres enough fluid capacity to help clear the crud.

Good luck
Dave