BackFlushing Radiator and Engine
 

I got my new water pump and I plan on backflushing while I do the install. I've read many threads and seen the way many have done it. I commented in a thread about trying it with a water transfer pump. It is capable of higher pressures as I used to run a couple of lawn sprinklers off it years ago. I also filled a thousand gallon tank with several times and it would do it pretty quickly through an inch and half hose. I don't know what the maximum pressure is but the volume. Is pretty high. What do you guys think would be the max pressure I would be safe with? Obviously I'm more worried with the radiator?

I have a 500 gallon tank full of water sitting about 10 feet high on a platform in my shop that I could gravity feed but I think I could pee more pressure, not volume :(. Thought I would just use the transfer pump from that and get a good woof to it. What do you fellows think of that idea? Am I over looking something?

Re: BackFlushing Radiator and Engine
 

Have been through this myself.


You can do the block and radiator separately, or do them with as an intact cooling system.


When doing it as a system or when doing the radiator by itself, do not use much pressure, Model A Radiators are high volume low pressure, and you can destroy a radiator quickly, especially if it is older/weak.


You may want to consider at treatment of Dawn dishwashing soap 1st to insure the cooling system is clean of oil/grease. Typically happens from someone over greasing an original style water pump. Do this 1st especially if using rust911 or thermocure, these do not remove grease/oil.


Then a treatment or 2 of Rust 911, or thermocure. These only go after rust/scale, and do not affect metal/rubber/plastic/etc. surfaces, so are very safe to use.


Or you can use white vinegar. But if it develops a leak and gets on paint, can cause paint damage. If you do not have a leakless water pump, vinegar can flush out the grease in the water pump, and it leaks all over the engine compartment if you treat by running the motor. It alos may go out the hood louvers and get on the car exterior. With white vinegar you must do a final treatment of water/baking soda to neutralize the vinegar that has microscopically imbedded into the cooling system internal surfaces.
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You can treat the block and radiator separately, or together as a complete cooling system.


If treated together, add the treatment, run the car on the road for up to a half hour or so for a couple of days, up to a couple of weeks. Drain, back flush through the lower radiator hose up through the radiator through the block and out the block coolant inlet. If using white vinegar do the water/Baking soda treatment.


If doing separately you can block the block inlet and the radiator outlet and fill and let it sit. Or you can rig a circulating pump on a timer to circulate every so often for days. Again a treatment of water baking soda if using white vinegar.


When completed, add a Gano upper coolant hose filter to keep future crud out of your radiator.

Re: BackFlushing Radiator and Engine
 

Reread you post again, did not really directly provide direct answers. Especially on older radiators I know of couple of people that have ruined a radiator backflushing using a garden hose at house supply full pressure.


I prefer treatment where the treatment is in the system and driving the car, and low pressure backflushing with the garden hose turned down.


Others may be able to provide safe ways of using a pump.

Re: BackFlushing Radiator and Engine
 

See attached article.

Tom Endy

Re: BackFlushing Radiator and Engine
 

Hot water industrial pressure washer with chemical degreaser,Ive saved a few radiators others have junked.back flush radiator (removed from car) and 'forward' flush,the hot water expands the radiator,the degreaser breaks up the clogged tubes

Re: BackFlushing Radiator and Engine
 

I wish some body were making those tools Tom was showing !!

Re: BackFlushing Radiator and Engine
 

Reproduction radiators are no where near as heavy and robust as original.Round tube funnel top 28/29 radiators are suitable for construction equipment :) and will stand the vibration and stress better than some of the lower cost reproductions out there.

Re: BackFlushing Radiator and Engine
 

Water/soda treatment: Please explain. How much baking soda to three gallons of wat soda to three gallons of water?

Drained my system. Filled with three gallons white vinegar. Ran a couple of hours. Flushed with water. Refilled with distilled.

Water pump now dripping. Going to try repacking first. Grease the back fitting with water pump grease. Any suggestions short of replacing pump?

Do you favor the original style packing? The teflon? The graphite foil?

Re: BackFlushing Radiator and Engine
 

The hose adapters are easy enough to make. I got holesaws to match the hose IDs and the garden hose adapter fitting OD to use on chunks of 2x4. I used adapter fittings that had a female hose end and a male 3/4” npt end.

Re: BackFlushing Radiator and Engine
 

Thank you very much !!

Re: BackFlushing Radiator and Engine
 

After treating with anything acidic (White vinegar, muriatic acid, etc.), neutralize the remnants of they acid in the cooling system with water/baking soda. Flush/backflush thoroughly a couple of times with water. Then use about a cup of baking soda/water mix. Run it in the A for a couple of days, then flush/backflush thoroughly. Repeat the water baking/soda treatment one more time.


Yes, the white vinegar does remove the grease/oil. Most of the time your pump will leak afterwards. You can try greasing it, do not over do it, only enough is needed to fill the packing nut, typically only a very partial pump on the grease gun. To be thorough repack the lead. If using the "washer" style packing, use two, and install so the split in the washers do not align.
Also add some grease to the washers. Usually the flush will not damage the pump, it is just the grease is part of the sealing of the shaft.


When tightening the packing nut down, only tighten enough to stop the shaft from dripping/leaking, do not over tighten. Keep an eye on it, tighten as necessary. Run water/rust inhibitor coolant until you are happy with the pump being sealed, then switch over to 50/50 green antifreeze if that is what you want.


Sorry I can not comment on which type of packing to use. I decided to run antifreeze, and at that time decided to run a leakless water pump to reduce the chances of getting antifreeze in the engine bay and possibly through the hood louvers and onto exterior paint.


I did get improvement performing the flushing/backflushing of the radiator/block/head, etc. However ended up replacing the radiator - wlth the help of Ford Barn discovered my problem was having an aftermarket 2 row core radiator that did not have enough cooling capacity.

Re: BackFlushing Radiator and Engine
 

Here is my version of Tom's tools.


Automotive freeze plugs, and some garden hose repair fittings, and a cheap inline shutoff valve adapter.


Drill a hole slightly undersized for the hose fittings and press the garden hos repair fitting in.


Instead of using just one freeze plug per adapter, use 2 and glue them together, otherwise a single wide has a tendency not to stay in place.


Simply insert them into the existing radiator hose, and use the existing hose clamps. If they leak like mine did, I just wrapped some electrical tape around so it would fit tighter in the coolant hose.


Cheap/easy to make. Works OK for occasional use.

Re: BackFlushing Radiator and Engine
 

What I did that made a huge difference, 30CCPU basically said above. First I filled the cooling system with distilled water and added a tab of dishwasher detergent to degrease. Ran it for a couple days and drained, looked terrible. Then I added thermocure, following the directions on the bottle. Ran for about a week and drained, completely black. Had to flush many times with water to stop a foaming issue but now the top tank of the radiator looks like clean brass instead of a rusty mess.

Re: BackFlushing Radiator and Engine
 

I agree with ryan, both methods work. I have also used thermocure in addition to the white vinegar.


Nice thing about the thermocure is it actually "dissolves" the rust, where white vinegar you can get flakes of rust coming out when you flush/drain.


Thermocure (rust 911 is another product) is more expense, but you do not have to mess with the Baking soda/water treatment, or have to worry about flushing out the grease in your pump, or worry about getting vinegar all over your engine bay and on your exterior paint causing paint damage.


Do not remember if mentioned, recommend installing an upper hose coolant filter, at least for a while. In case some trash got loosened up you do not want it plugging up your freshly cleaned radiator. You can always remove it after a while if all is OK. The Gano filter is the most mentioned filter. There are other alternatives. I personally do not recommend using a sock or nylon/panty hose. Have heard of cases they break up and ending up in the radiator plugging it up.