The Stovebolt Site Forums The Shop Area Engine Shop Engine Flushing

HI,

Can some explain the steps to flush an engine block as well as what the chemical is best to use. I was at a CarQuest store and they have 2 types of flushing solvent/chenmical. I would like to flush the engine and add fresh antifreeze to it. I plan on having the spare rad. dipped and cleaned before replacing the one that truck has now as it has a really big dent in the top.

Jake

I use a two part radiator flush, I think it's Dupont, comes in a can and is a powder. Follow the instructions on the can. I get a little sloppy with how long to leave it in the system. The one thing I definitely do is flush it real good till the water is clear. I've had good luck with it no real problems. In addition to the antifreeze I also add a can (bottle?) of rust inhibitor and water pump lube. Hope that helps.

Larry

I'll second Larry's recommendation. For a rust inhibiter/pump lube, I have used Red Line's Water Wetter. It's also a surficant that helps the coolant be more efficient at transferring heat. Not to sound like a commercial, I did see about a 10 degree drop in temp during in town driving.

If you're having the radiator cleaned, you don't really need the chemicals.

I usually hook a garden hose with a control valve to the upper heater hose nipple. Plug the hose you just unhooked. Disconnect the lower radiator hose and start flushing. Don't turn the sose on too fast, it will blow out the heater core and radiator. When that's clean, open the block drains and flush. Once that's all clean, remove the plug you installed in the heater hose and flush. Then let it all drain and put it back together.

sodium carbonate , also known as washing soda, is an excellent anti-rust agent and surfactant - worth the pennies for a flush

Bill

Lots of good suggestions for the flush, and the antifreeze in the proper proportion, will keep it running cool.....but you'll be doing yourself a favor if you spring $1.00 for a couple gallons of DISTILLED water. On a 50/50 system you'll be pleasantly surprised at what DOESN'T build up in your radiator.

Once you've got the system clean why not keep it clean? Hope this helps.

His question is on flushing the block, not the radiator which he says will be cleaned by a shop. So does this radiator flush stuff work on the cast iron engine as well as the copper radiator?

use flush per mfg,,,remove thermostat and hoses flush forward and reverse with hose all systems block and radiator,,heater...doc

For a commercially available flush, the DuPont 2-part powdered stuff is the best available. The reddish powder (cleaner) forms a weak acid that attacks lime and rust deposits, and will clean the block and the radiator core. It will also clean the rust deposits that are keeping a rotten freeze plug from springing a leak, or clean the lime deposits out of a pinhole in a radiator! The white powder is just an acid neutralizer, industrial-strength sodium bicarbonate, better known as baking soda. Follow the package dirtections, and be sure to run the neutralizer long enough to kill the acid, then do a good rinse with lots of clear water.

For the really badly clogged ones, do what I did when I was running the maintenance shop at a concrete plant- - - - -Put about 8 ounces of concentrated muriatic acid in the radiator, run it for 30 minutes at a fast idle, drain, refill, and add two boxes of baking soda and run for 10 minutes. Drain and flush thoroughly with clear water. That process will clean out anything, including cement residue! Don't ask me how it got into the cooling systems, but it was a chronic problem!
Jerry

You can spend any amount of money with these flushing compounds. Some of them will eat up your rad, your heater core, and once in a while a head gasket. The best and cheapest thing to use is Sal Soda, made by Arm&Hammer. Its nothing more than washing soda, one would have found in the wringer machine days. Probally has the same stuff in it that Bill posted about. I used it yrs ago, just put a couple of cups in plain water and drive the truck aound a 1000 miles or so. It cleans up all the junk left in the block and rad, and dont harm anything. A lot of times overheating in these engines is caused by crud build up in the water jacket located along the length of the left side of the block. The water doesn't flow though here well, and build up keep the water from drawing the heat out of the metal along bottom of the cylinder walls. This passage ends at the drain cock at the back of the block. Removing this plug and getting in there with a long brush, similar to what is used to clean a commerical coffee maker will help knock the stuff loose. There is also a frost plug at the front end of the motor that can be pulled, and the same thing done there. Makes a world of differance if you have constant overheating trouble.

yes Jeff, Sal Soda is Washing Soda is Sodium Carbonate [still found in the laundry products section of yer super market] ... a surfactant, wetting agent, and alkalinizer [anti-acid] ... it's what's used in the electrolytic derusting process, and neutralizes/loosens/disolves deposits from hard water

I'm amazed every time I poke around inside the old bottle washer, all bare steel and cast iron with never any corrosion or rusting evident

Bill