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Discussion Starter #1
So i thought i solved thge overheating problem, NOT. I was on my way to have extensions made for the headers when bad it dies, it has overheated and boiled again. Darn, anways get it towed take out the thermostat (it was spraying out of the housing when it boiled) My guess, thermostat is stuck closed or not opening all the way, as well as block is still crammed full of rust and build up. Now for the questions, Which chemical do i use to flush the block completely, i want something that is extremely strong, and that i can let it sit for a while then flush it thuroughly with water, i read a post awhile back about a some chemical a guy used to flush out his cooling system and said it worked very well. Also housing is leaking, i hvent used sealant yet, but i think that is the next step in sealing it, im also gonna try double gaskets. Last question thermostat is a 180, put in boiling water and it opens around 195-200, obviously bad so im gonan get a new oen tomorrow, but the thermostat is only opening about 1/2" seems like it shoudl open more. When i force it open it seems like its blocked but with enough force itll open up all the way. So how much does the thermostat open?

I know its alot of questions and alot of rambling, so any help and answers are wonderful

doing my best to get my car on the road for the first time since ive owned it
thanx again guys
 

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It's not so much the block getting plugged off with rust, as it is plugging the radiator. It doesn't take a lot to plug a radiator to where it won't cool the car.

There is no chemical that will help your problem if rust particles have plugged off the radiator. A flush only attacks limey deposits from hard water, so not a good idea in your situation.

The only way to do any good at all with a radiator plugged off with rust particles is to remove it, turn it upside down, and reverse flush it with copious amounts of water. That may not do it. It may need to be cored out by a radiator shop. Then, it can plug off again in just a few minutes with rust that is still in the block. This is where a Gano, or similar filter can save your butt!

Until your radiator is cleaned out for adequate flow, your car will not run cool, no matter what you do. Good Luck!
 

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Discussion Starter #4
thanx alot guyz, ive flushed the radiator by backflushing and forward flushing many many times, but i will continue to do so until i get this thing running cool

anyone know about how far thermostat opens up?
 

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I highly recommend that you consider draining the block. Look for plugs along the bottom of the block, one one either side, one near the front the other near the back. Rust is heavy and will settle in the lowest point, no matter how many times you flush the block without taking these plugs out, crap will still remain behind.

I removed these plugs and ran water only into the thermostat opening until it ran clear. I replaced the plugs (1/4 NPT) with radiator petcocks so it would be easy in the future to drain the coolant.
 

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Discussion Starter #6
are you talkign about the freeze plugs or something else?
 

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Something else, I think the ones in mine were 9/16 head size. Right (passenger) side is near the front of the block. The ones on my stroker block are 1/4 female allen head.
 

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1/2 inch is about right for opening. When you buy your new thermostat test it in some water with thermometer. Heat the water in a microwave (its faster that way) until you get to just a bit before the rated temperature (say 175 for a 180 thermo) put in the thermo and see if anything happens. Take it back out heat the water just a little more (180 target) see if the thermostat is starting to open. Then heat to 185-190 and see if it is all the way open.

FYI- You can check the max opening by putting the thermo in boiling water (212 degrees at sea level, slightly less for those of us not on a coast or in death valley).

John Harvey
 
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