How To Flush Straight 8 Cooling System?

[Guest shadetree77]

I'm going to have my radiator boiled at a local shop but I would like to flush my straight eight as well while the radiator is out. How should I go about doing this? Should I just remove my block drain and run the water hose into the block? By the way, I'll have my entire cooling system removed at the time I do this. Water pump, thermostat, all hoses, radiator, all of that will be removed at the time. I'm thinking I could just run the hose into the upper radiator hose opening until clean water comes out all of the openings in the block but I wanted to make sure before I did it.

[danhar1960]

You might consider going all the way and remove the welch plugs in the side of the block and using a bit of wire to get all the sedimented crap out from the bottom and around the cylinders. You'd be surprised at what accumulates down there over 50-60 years. Its that stuff dislodging that may stuff up your fresh radiator.

Danny

[Guest shadetree77]

I did consider that. I don't know if I want to remove those plugs right now though. I was told I could get a radiator filter/trap that would catch any of that junk should it come dislodged. I've never used one before but it seems like it would work. They are actually made by a guy in Australia. Here's a link to his site. Ever heard of this product? TEFBA :: Engine cooling system Radiator filters :: Easy to CLEAN

[Pete O]

I had my cylinder head off to deal with some bad pistons, and was astounded by the amount of sediment toward the back of the engine, particularly around cylinder 8. The water passage was nearly half way blocked with a rusty muddy gunk. I picked at it with wires and drain snakes and compressed air and power washer until I got as as clean as I could. After putting it all back together, I ran it with a stocking in the upper hose of the radiator for a while, and I cleaned out more crap from the stocking about once a week. She runs a lot cooler now particularly at high speed, so it was worth it. No matter how clean you get your radiator, the hot running will continue until you get the water jackets opened up.

[avgwarhawk]

Another trick to strain the fluid running to the inlet of the radiator is panty hose. Wrap a patch of panty hose at the inlet of the radiator. Place the radiator hose over the patch and inlet of radiator. Tighten the clamp. Run the motor. Sediment will collect at the panty hose. Rinse and repeat until no sediment is captured in the panty hose. Return the panty hose to your wife.

[old-tank]

Robert

Chemicals, boiling and flushing a radiator is nearly useless. The only way to open the plugged tubes is to have it rodded. This is where the top tank is removed, low pressure water is run constantly into the lower hose opening; this will show the plugged tubes. Then a flat rod is introduced into each plugged tube to push out the clog. The top tank is replaced, leaks are repaired and you have a good radiator.

Flushing the block will not give good return on the effort. Most of the heat load is around the combustion chambers, meaning the cylinder head and the upper part of the cylinders. Other than reducing capacity the sediment has little effect (many race engine have concrete added to the lower part of the block to increase strength).

Willie

[Pete O]

Robert

...Flushing the block will not give good return on the effort. Most of the heat load is around the combustion chambers, meaning the cylinder head and the upper part of the cylinders. Other than reducing capacity the sediment has little effect (many race engine have concrete added to the lower part of the block to increase strength).

Willie

I can only comment on what my own experience was. Prior to cleaning out the sediment in the block, anything over 50 mph and the temperature would just keep increasing. After cleaning out the sediment from the block, can drive 65 all day long without the needle moving. Made no other changes.

[Guest shadetree77]

Thanks for the suggestions guys. I called my radiator shop today and they said it would be around $45 to boil it and pressure test it. I'll call them again tomorrow and see how much it would be to rod it. I'm guessing a good bit more since that involves taking the top tank off. You guys ever hear any horror stories about doing that? I would really hate for them to poke a big hole in the radiator. That would leave old Lucy stranded for quite awhile as I definitely do not have enough funds in the Buick account to re-core it! I think I'll at least run some clean water through the block with the drain removed. I don't see how that could hurt anything. I won't be taking my cylinder head or freeze plugs off anytime soon so a little flushing will have to do for now. Thanks for the panty hose suggestion too. I'll raid the wife's dresser drawer when I put all this stuff back together. A pair of panty hose and a mildly pissed off wife are a lot cheaper and easier to deal with than that filter contraption! Well......maybe.:D

Edited May 10, 2012 by shadetree77 (see edit history)

[Ben Bruce aka First Born]

Behind the distributor, down low.

 

  Ben