Truck is a '55 with a 223. The coolant does not seem to be moving. The truck does not idle as well when it gets warm and is hard to start once warm.

We replaced the hoses and stat last night. Filled the radiator, started it up this AM and the coolant did not drop at all (It's still not moving). Lower hose has a spring in it and is not collapsing so this isn't the issue. We we do have coolant at the heater box (we know this as we had a loose hose clamp and coolant leaked down the firewall).

Our next replacement item is the water pump. Thoughts?

Phil

 

First thing I would check is the thermostat. Pull it and put it into a pot of water and heat pot of water. T stat should open when water gets to T state marked temperature. You can run the truck for a while without the T stat. Make sure you have all the air out of the cooling system.

So I went back and re-read your OP. My SWAG is air in the system.

 

^^^ I agree, check the t-stat first, then the only other logical thing would be the water pump.

 

If you take the thermostat out temporarily and look in the radiator (be sure it's full.) with the engine running the water should be circulating. If it is not you either have a restriction in the system or a broken water pump. It should only cost you a gasket to pull the water pump and check it, once in a great while and impeller will come off the shaft.
I am a bit curious tho if you really understand how the system works? The thermostat is a simple valve that is designed to be closed and restricts the coolant from circulating thru the radiator until the coolant in the engine block reaches the rated temp of the thermostat. At that temp the valve opens and the coolant can circulate thru the radiator as well as the engine and heater. There would be little to no movement visible in the radiator neck until the thermostat opens. If the thermostat is stuck open, the water would be seen to circulate even when cold. If the thermostat is stuck closed, or if the water pump is broken, the coolant in the engine will continue to heat up until it overheats and boils over. If the cooling system has a problem you would not be able to run the engine for more than about 10 minutes without overheating, it would not "get warm", it would boil over. If it is not boiling over, the cooling system is working.
The engine not idling as well or being difficult to start when warm, is not a cooling system problem. Those are usually symptoms of a worn engine or one needing a full tune up (my guess would be the worn out engine). Typically the engine rings are worn, stuck, or cracked. When the oil warms up it's not thick enough to seal the cylinder compression and gives the symptoms you describe. Did you change the oil recently? If so I'd bet you wanted to be good to your truck so you used some higher priced "good" oil with a multi-viscosity rating like 10W-30, 5W-40, etc or one of the synthetics or synthetic blends??? The multi-viscosity or synthetic oils are designed for newer engines, They are not suitable for pre 70's high mileage engines. While you are saving up for your engine rebuild/replacement, go to the auto parts store and get a case of straight 30W detergent oil and change the oil. If the drained oil smells like gasoline, better get a second job, that rebuild is coming soon.

 

I have always had a problem with seeing the water circulating on my 223s. The real test is using a good temp gauge or thermometer in the radiator. Some 223's have an issue with NOT warming up enough. Personally, before changing out the thermostat, verify what temp it is actually running at. It's easy to screw in an aftermarket temp gauge to check. ALSO, BE VERY CAREFUL when installing a t-stat back on the housing. If the thermostat is a little off when tightening you can easily crack the housing. Don't ask how I know. Use a little grease on the t-stat to hold it inside the housing when reinstalling. Don't overtighten the nuts either. If you have hot coolant in the heater hoses something is working right.

As for the idle issue, check timing, check fuel delivery, is your carb idle set correctly? Has your carb been rebuilt? I recently rebuilt my 1904 and WOW the difference. Idle almost never has anything to do with cooling. What is the condition of your vacuum advance on the distributor? Is the diaphragm flexible or rotted? If in doubt, NAPA has the correct vacuum advance.

 

And while you're checking the T-stat, make sure you've installed it correctly with the coil toward the engine. Many housings allow for the T-stat to be installed backwards.

 

First thing to check would be -- is the belt tight enough? Before you start spilling antifreeze.

 

I think I have found the issue. I had replaced the thermostat and hoses last night. When I replaced the thermostat, I installed it the same way I took it out...with the spring facing the housing. After doing some research, this is backwards (spring not facing the engine).

I assume this is my issue?

Phil

 

Won't fix the idle and start issue.

 

What carb are you running?

 

Yeah, I understand the starting issue wont be fixed. We believe there may be a timing issue, so we will check this next.

As for fuel, it has a brand new 1904 carb and new fuel filter. We've played with the idle adjust multiple times.

It starts up very well (1st try) when cold...just not when hot.

I appreciate all the advice as we chase this truck down!

Phil

 

New, NOS, or rebuilt?

 

Run a compression check on all the cylinders cold then hot. I think you'll find your hot start problem. One other possibility would be the carb is leaking into the intake (float set too high, fuel pressure is too high, needle leaking, idle too rich, ?) at idle washing down the cylinder walls, putting liquid gas in the intake, and/or flooding the plugs. When you do the hot compression test, examine the plugs. They should not be wet looking or smell of gas.

Best way to set the idle mix is with a vacuum gauge and tach.

 

Carb is a reman and purchased from Rockauto.

Thanks for the advice, a compression test is on the list of to-do's over the next few days along with the timing.

The carb does seem to run very rich, especially on start up (strong burnt gas) and even with both garage doors open you get a pretty strong burnt fuel smell thats enough to bother your eyes after about 10 mins of idle in the garage (both garage doors open).

We got the thermostat flipped around and all is good with the cooling system. I can't explain it, but now it starts hot on the 1st try and it didn't before. 4x we ran it for 10 mins (up to operating temp) then shut it down to let it get "hot." When the temp gauge climbed up 3/4 of the way, we restarted it and each time the truck started (on the 1st try!) and dropped back down to operating temp within a few mins., just sitting there. So the cooling system is now definitely working.

Phil

 

OK! Problem 1 fixed.
Problem 2: rich carb.
These carbs were always sensitive to fuel pressure. A little too much pressure and the needle is pushed off the seat. Did you replace the fuel pump along with the carb? The easiest solution is to put an adjustable pressure regulator in the line just before the carb. Even tho it is a rebuilt carb, they really aren't checked for leakage before they go out the door, so it's possible the carb is leaking raw fuel into the intake. Take the air cleaner off and use a strong flashlight to look into the carb while the engine is running. Look for any liquid gas dribbling into the engine. Check at a couple different throttle settings. IIRC that carb has an idle needle that has a point that lines up with a small V notch in the throttle plate. Make sure it is not screwed in far enough to keep the plate from closing fully. Usually turning the mixture screw all the way in (just till it stops, don't overtighten) then back it out 2 1/2 turns will be close to where it needs to be. Buy a vacuum gauge, they are inexpensive, and temporarily T it into the vacuum line on the carb. With the engine fully warmed up and the choke fully open first adjust the idle speed to spec, then adjust the mixture screw until you get maximum steady vacuum reading. If the idle speed changes, reset it and readjust until you have max vacuum at the factory idle speed. Remove the vacuum gauge and reinstall the air cleaner.
One more thing, these engines can be sensitive to the proper starting method: If the engine is cold, set the choke by pressing the gas pedal down to the floor (do this gently, not like you are gunning the engine, you don't want a big shot of gas from the accellerator pump!) then let it gently return fully. Now push the pedal down 1/4 of the way and hold it. Turn the key, the engine should start. Avoid pumping the pedal. If the engine is warm, the choke should already be open, so just press the pedal 1/4 way down and start. If it doesn't start while cranking to the count of 5, release the key and the pedal. Repeat the pedal to the floor, release then hold 1/4 and try again. If it doesn't start after 3 attempts, the engine is likely flooded by now (especially if you can smell gas) so gently press the pedal to the floor and hold it there while cranking the engine over until it starts. As soon as it starts, release the pedal to 1/4 open until the engine is running smoothly then release to idle.
Note two things: 1. don't press the pedal fast. 2. don't pump the pedal.