I have a 1950 F2 with 239 rebuilt about 2000 miles ago. It has new water pumps and I put in 180 deg thermostats. What happens is the bank that the heater is on runs cooler then the othe bank. It opens thermostat bout 3 to 5 minutes after the other side. I tightened belt. I guess what I asking is this normal? Also, sometimes after running a while the overflow tube will spit out coolant. Checked temp and is around 190 to 200 when it happens. Can it run without thermostats to help or not?
Ran this truck the past 4 years without issues longest runabout 1 hour at 55 mpr.
I can put on overflow tank? What have you all done to keep it running cool?

 

Your one thermostat has gone bad, or at least isn't operating the same as the other. But how do you know one side is different? Thermal laser gun? or do you have individual temp gauges?

Your description sounds like the heater side (PS) opens later but runs cooler?!

Run 160-deg thermostats, they give plenty of heat even in winter, and at least on my engine give me a minimum of 180 deg. operating temps, 190 on a hot day. I would also only use NAPA thermostats, p/n THM 530060 for the 160-deg.

 

Thanks for info. Had 160 deg in them but came from Mac's. Will get the other ones.

 

I used thermal gun at the base of the thermostat to check.

 

Here are the numbers I found after a hard run uphill, on a 95 deg day, with 160 deg thermostats:
Location.................... temp
Top tank ....................173-179
DS head (center).............183
PS head (center)..............183
DS thermostat housing .....173
PS thermostat housing.......179

 

I have heard conflicting stories about one side running hotter for years. Typically these are from folks with two cheap temp gauges installed, one per side. I suspect their differences are due to thermostat and temp gauge variations, not due to anything inherent to the engine.

If you fill the radiator all the way up it will burp coolant. A large overflow tank will take care of this as long as your radiator cap allows coolant to be pulled back in.

What fan are you running (4 blade, six blade, aftermarket, etc) and do you run the factory shroud?

 

If you have the right radiator cap for your radiator (not pressure but measurement from sealing surface to pressure seal when compressed) you might get excessive burping. Not every radiator is the same. But some burping out the overflow is normal at first.

Ross's measurements are a great guide. There are other things than thermostats that can cause one side to run hot. The obvious is some sort of restriction or an air bubble. Since it is on the driver-side with no heater to bleed it the air dam would seem most likely.

Other things like a vacuum leak either from an intake manifold seal or a leaking accessory like vacuum wipers or distributor vacuum advance could be the culprit. Backfiring can cause that.

Less likely are burned valves but here is a good chart for you to do simple but very effective old school checks:

 

Usually these anecdotal stories are that the heater side (PS) is the one that runs hotter, presumably because it recirculates the water that goes to the heater.

I put in new NAPA thermostats in '13 after a rebuild, and drove it all over with no problems. Then last Fall, coming back from Truckstock, on the long climb back into NM, I saw the temp gauge rising on hills. It was maybe 1-1/2 needle widths rise, in not particularly hot weather (high 80's). On the downhill side it would drop back slowly. When I got home I pulled both stats and put them in a pan of water and turned on the heat. The temp gauge thermostat opened at the same time as the other, but as the temps rose, it simply stopped opening while the other kept going. Replaced that one and no further issues.

My point being, these aren't precision pieces, and they do go bad in a variety of ways. The problem with this stat didn't show itself until it was under heavy load at high speeds. Driving around town it was just fine.