On my 57 Bird with a 312 it's doing the normal "getting pretty warm while idling in traffic" . I flushed the coolant system, put on a 6 blade fan, installed Casco's modified water pump, used the big thermostat and choked down the by pass hose but nothing helped at all. As long as I'm moving it runs at normal temp. Before I spend the big bucks on a big radiator I've heard of people back flushing the coolant system. How do you do this? Any help would be appreciated. Thank's, Lex

One way is to buy a small kit from Prestone. It has a small inline valve/garden hose adapter you would install on the heater hose. I use one on my bird, although, I don't much need it anymore. If if yours hasn't ever been back-flushed you'll more than likely get a bunch of crud out of the block. That's a good thing, although it's not guaranteed to fix your issue. but won't hurt to try it. Full instructions on the package. lots of google articles and videos.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

Do you have an idea of the actual temperature that "pretty warm" is? An infrared reading of the temp of the thermostat housing is a good indicator. Mine runs 100º to 105º over the outdoor ambient. That's hot idle after a drive, standing in the driveway to stabilize, pop the hood and check it.

 
 Steve Metzger       Tucson, Arizona

When the gauge is on the high end of the line but not to the H the infrared shows 232. It's never boiled over on me but I've never had to sit still for over about 5 minutes.

What sort of spark advance are you running at idle? The stocker initial setting with ported vacuum on the distributor?

With regard to the flushing - I got a lot of crud out of mine by giving it a huge dose of white vinegar - warm - and letting it then sit over the weekend. I did that twice and then did several plain water changes (just draining the radiator). Got a pro to do a thorough rod out of the original radiator.

After the trials I've run, all I'm missing is a higher capacity water pump (have a small pulley on the original) and of course as you say the biggy - a bigger, better sized radiator.

 
 Steve Metzger       Tucson, Arizona

I bought the Prestone backflush kit and took the thermostat out. I drained the coolant and filled it with water and put a bottle of Peak Radiator Flush in it. I let it idle in my driveway for about 30-45 minutes with a thermometer in the radiator and it never got over 190 even though the temp gauge was a little past 3/4 of the way hot. Guess it really wasn't getting as hot as the dash gauge showed. I back flushed it and didn't get any rust or crud whatsoever. I don't think this engine is that old. I remember when I checked the valve lash it looked like new in the head valleys. Guess I'm just going to run it as is. Thank's all!

Further to what Steve said quite a few flathead guys do the vinegar trick but put some bicarb in the next flush to neutralize .

With what you have done just pull the radiator and get it rodded I don't think you'll have a prob.



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