So I'm getting ready to drive this thing.  Now that the engine is running, tires are and brakes function I'm paying more attention to the cooling system.

I haven't run the engine for too long yet.  Just enough to get the temp gauge clost to the "H".  Then I've always shut it down.  Well today I went out to get some more data specifically on the cooling to try and determine if it was ready for a drive around the block.

I left the radator cap off and started the car.  The water doesn't move, but I'm not sure it should until the t-stat opens? At one point, after a few minutes of running, the coolant level suddenly raised up into the filler neck, really quickly, and I thought it was going to fly out of the filler neck...but it seemed to stop but before I could tell for sure I quickly slammed the cap on the radiator.

I left the engine running, and I had an infrared thermometer, the temp just behind the t-stat housing on the intake was about 180, the upper hose was hot.  But when I pointed the termometer on the radiator itself it only read 50 degrees (about 40 outside).  The temp of the lower hose was similarly 50 degrees or so.  I also carefully grabbed the lower hose and it was ice cold.

Is something wrong? Should the lower hose be cold?  What happened when the coolant level quickly raised into the neck?  I left it run a little while longer but the lower hose and radiator didn't seem to be warming so I shut her down.  The finaly temp behind the t-stat housing was around 210-220.

I don't know what temperature t-stat is in the car.  Ideas? Education?

Nate - Madison, Wisconsin

 

56 Ford Customline Sedan

 

You're right - water shouldn't flow until the thermostat opens with a stnadrard thermostat. The top of the tank - above the core - is usually empty at start, that is the "overflow tank" for the system when its warm. 

I believe it would be a good idea to replace the thermostat. Napa #6 (or #7?) - a really low Napa part number - is a 170° large opening, free flow thermostat that is sized for the Y-block opening. many have great results with it.

Make sure its installed pointing the right direction and run your test again.

There also could also be a bunch of crud in the radiator judging from your heat test - a collapsing lower hose - that sort of thing, to sort out.

 
 Steve Metzger       Tucson, Arizona

It's a good idea to replace the thermostat anyway. Sounds like its not opening. Once the thermostat opens you will see some movement of water in the radiator. Especially if you rev the engine a little. By the way do this from the side. Never lean over the fan when you rev an engine. If it breaks the damage can be life threatining. Just not worth the gamble. Once the thermostat is correct check the hoses. A soft bottom hose can suck shut and restrict water flow. Thats why they have the spring inside them. Keep us posted! Chuck in NH

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

If I recall, the car had been sitting awhile before you got it right? Sounds like there might also be some blockage in the radiator cores? I would just double check by opening the petcock at the bottom to see what you get out of it. Probably best to open up that t'stat housing and put a new one in there. Don't forget that in addition to the one bypass hose (on the tstat housing) you can also rig up another by pass hose from the top of the intake manifold (heater nipple or valve will sit there) and the side of your water pump. In essence, this is where your heater core lines are going back and forth to, but you can speed things up by hooking up a temporary line. One last tip...be careful with the metal bypass tube that attaches (with two bolts) at the top of the water pump...they can bend/crush pretty easily if there is a lot of corrosion.

Daniel Jessup

Lancaster, California

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

Thanks for the thoughts guys. I did drain a bit of coolant from the petcock and replaced with some new fluid...just so I could feel like the coolant was at least half new.  The coolant in there didn't actually look too bad...forgot to take my coolant tester.  It could've been replaced 6-7 years ago when my grandpa and a friend got her running in an attempt to sell her.

So if coolant drains out the petcock, does that mean the radiator isn't plugged up?

The lower hose isn't collapsing, it has a spring in it and the rubber is soft, I can squeeze it...but it kept its form during this test.

I didn't realize the coolant isn't supposed to be in the top tank.  It was definitly too full becuase even cold that top tank was almost full.  What do you make of the coolant suddenly rising into the filler neck as the engine warmed? 

So does the coolant flow into the top of the tank from the t-stat?  Or does it flow into the bottom?  Would the bottom hose only get hot once the T-stat opens? 

I will definitly get a new t-stat in there.

Nate - Madison, Wisconsin

 

56 Ford Customline Sedan

 

There is supposed to be coolant in the top tank. Just not up to the top of it. The level should be about inch or so down from the top.



I agree about the thermostat - replace it. NAPA # 6.



You can check the radiator for a clog by putting your had on the fins after warming up. The temp should be pretty much even all over. If you have cold spots, the radiator need service.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

So does the coolant flow from the top hose down to the bottom of the radiator or vise versa?

I'm still trying to decide what it means that the top hose was hot...but the radiator itself and the lower hose were cold.  Could this happen with the t-stat closed?  How would the top hose be hot if the t-stat were closed?

I suppose it could be partially opening or something like that.  Dang...now I can't wait to get back and try a new stat.  Thanks for the tips.  I will be careful of corroded parts.

Nate - Madison, Wisconsin

 

56 Ford Customline Sedan

 

Nate:

Yes, the hot water comes up the top hose, down through the radiator, and the cool water goes to the water pump and back through the engine.

John - "The Hoosier Hurricane"

And to add on a couple more water paths......

There is a 5/8 "bypass hose" coming out under the thermostat and directly back to the top of the water pump. So that when the engine starts cold, there is a "short circuit" to recirculate the coolant for a while and raise the engine to operating temperature. This flow path being right under the t-stat housing makes the engines heated water travel to that point and when there is sufficient heat coming to it - heat and open the t-stat. This is what I think was happening - the t-stat was stuck and you were only recirculating water.

There is a vacuum operated valve on top of the intake manifold (the front crossover water passage), directly behind the thermostat housing - that goes to the heater. A control valve under the dash throttles this valve when heat is required by the interior controls. When the interior valve has failed - it used to be common practice to replace the vacuum operated water valve with a 90° hand shut off - on for winter off for summer sort of arrangement. Water from the heater returns to the upper passenger-side of the water pump.   

 
 Steve Metzger       Tucson, Arizona

Thanks Hoosier and Greenbird,

It sucks not having my car at my house, so I can't go look at it, I just  have to visualize everything.  I definitly saw the bypass hose now I know what it is.

So you do you guys think that even with the t-stat closed enough heat would conduct through the t-stat (conduction through the metal) to heat up the water on th eother side of the t-state in the upper hose?  That upper radiator hose was pretty warm, i'd almost say hot.  I didn't check with the thermometer but it was nice and warm to the touch all the way up the hose.

I know you guys are all probably thinking..."just go change the stat and find out if it works".  I am going to I promise...but it will likely not be until this weekend so I have to sit all week in my office and just think about it...you guys are the outlet for my thoughts!

Nate - Madison, Wisconsin

 

56 Ford Customline Sedan