I am in the process of replacing the radiator on my 1956 Ford Crown Vic with 292-V8. I want to completely flush out the cooling system and drain the block by opening both drain cocks on either side. There will be no or very little liquid in the system. I want to refill the system with a 50/50 antifreeze and distilled water mix.

Do I need to put any 50/50 coolant back into the empty block before starting the engine or do I only need to fill the radiator initially and then start up and add 50/50 coolant to the radiator until full. I am afraid to run the engine with no coolant in the block. If I need to put coolant in the block, how is this done?

I got the car in an auction 3 years ago and know little about the condition of the thermostat other than it seems to be working ok. Do I replace it with a 160, 180 or 195 degree thermostat? I live in Louisiana - mild winters and hot summers.

Thanks in advance!

Danny

THIS IS GOING TO BE MESSY!!! LOL

Some of the other guys should chime in pretty soon here but I will give you a couple of cents from my end up here in Virginia...

I always use a backflush kit like the one Prestone and other Antifreeze manufacturers make. There is a T fitting in the kit that fits nicely into the 5/8" heater hose (I would usually flush my heater core separately, and simply use an extra 5/8" hose from the top of the intake manifold where a fitting or temp valve is located and the other end of the hose connected to the tap on the water pump. The T has an adapter that you can hook a regular residential water hose to. Usually these kits have decent instructions, but I would install the kit first with the old radiator and block almost full. The T in the kit should have a cap for it also.

I always completely flush out my block (as much as I can) before removing the old radiator... in the past I have used some of the Prestone or BG products to run the chemicals through pretty good. Once you have run the engine long enough according the products specs, then allow the engine to cool a little bit before completely draining.

Then drain the old radiator and block as much as possible. Connect your house water hose to the T fitting, keeping your block drain valves OPEN and your radiator drain cock OPEN. Take the cap off your radiator and have someone turn on your water hose maybe at 25% or so. Once the water level is up to the top of your radiator, start your engine and let it run. While the engine is running, be sure to check that your water level is being maintained towards the top and that your drain cocks are all flowing water... some blocks are bad enough that you need to stick a dental pick or some other item like a scratch awl to help clear debris.

Turn off your engine once the water is running clear from your block and from your radiator drain cock. Allow everything to drain.

Remove your radiator and check those hoses/clamps out too. I would recommend a 180 thermostat, but I know some fellas like to run a little hotter. Your Y block probably won't mind it... depending on what kind of radiator you are installing (2 row, 3 row, 4 row, etc) and its cooling capability, you may change your mind on the t'stat degrees. I know the new 4 row that I put on my father in law's car cools like there is no tomorrow so I put a 195 degree t'stat in his car.

Obviously, you can now remove the 5/8" hose and T fitting assembly and reinstall your heater hoses.

Check all connections and close all drain cocks.

Next, I personally like to fill with 100% water to check for leaks so I don't lose any antifreeze if there is a problem, but some guys skip this kind of step. Unfortunately Murphy's Law is in effect for our garage! Simply leave off the radiator cap and fill with water to the top. Start the engine and let it warm up, checking for that thermostat to begin opening up. Remember that the top hose is the hose that is going from the engine block to the radiator, and the bottom hose is the one that is going from the radiator to the block. It will take a while for the tstat to open... especially on a cold block or cold tap water, but it will open. In the mean time, the level of your radiator water may rise to the point of overflowing while you are waiting on that tstat to open. Remember that there is a small bypass tube so a small amount of water will flow back through the block.

Once you are satisfied that there are no leaks, you can open all drain cocks after the engine has cooled a little.

Then you can close the cocks again, fill the radiator with 50/50 and follow the same steps above.

This has always worked for me in the past and I have been very happy with the way the cooling system lasts in my vehicles. The only other thing that I would add would be to say that sometimes air becomes trapped in the system. Usually, removing the radiator cap, or removing a heater hose, filling manually, and then reinstalling can take care of those things. To be honest I have never had a problem with any 55 or 56 Ford car or truck with air pockets like that, but I am sure that it can happen.

apologies for the "windy" post, lol

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Thanks for the reply.

So what I think you are saying after the flushing, testing for leaks and re-draining is basically this:

The radiator and block are empty and that by filling the radiator, the 50/50 coolant will travel through the radiator into the block via the lower radiator hose and fill some of the block. When the radiator is full, the block will have some 50/50 coolant and will be safe to start up and run the engine at which point the level in the radiator will drop. Keep adding the 50/50 mix until the thermostat opens and the level in the radiator is full.

Is that correct?

Thanks,

Danny

I have 292 in F100.  I drained all the coolant by removing the heater hoses, removing the drain plugs on each side of the block, and the lower radiator hose. Then flushed the heater core in both directions with a garden hose.  Next I flushed the block though the heater outlet.  Lots of mud came out.

I used the Prestone radiator flush for 5 hours of running over a weeks time.  reflushed.  Again lots of mud came out.  I added Prestone radiator flush for second flush.  The water came out clean after the second flush.  I premixed antifreeze and distilled water refilled and life has been good.

A chemical flush will like turn up a leak or soon to be leak in the system.  Mine leaked at the water pump bypass.  I would test for leaks before adding $13 gallon antifreeze. 

Right on! You got it.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Really you should rip your radiator out and get it serviced [rodded out] after you've flushed your block, at least they are easy to get out. If you do a serach you will find a little modification that some of us do in regards to the bypass hose [maybe someone would be kind enough to put up the link] try a 170 thermostat. Why are you using anifreeze??? if your in a reasonable climate you shouldnt need it, dont use anything with glycol it doesn't cool well in non pressurised systems and if you have the slightest crack or pin hole it will find it ! find one that is a plain ol' coolant with anti corrosion, usually its used for motor sport [not slippery] .. easy..



"Came too close to dying to stop living now!"

Sorry , yes the system is still pressurised, Doh! I meant not like a modern pressurised system with an overflow.



"Came too close to dying to stop living now!"