The temperature gauge on my truck goes all the way to hot pretty quickly. I haven't run it for more than 15 minutes or so. It doesn't overheat to the point of the radiator spewing steam.

I have a brand new thermostat. I have opened the radiator cap while the engine is on and looks to me like the radiator fluid is circulating.

Is there a way to know whether the truck is actually overheating - or whether I have a bad temperature sensor - without just running it so hard it actually overheats?

 

A handy tool to use for a "second opinion" is an infrared thermometer. Fairly cheap these days. Here's a link to several.

Amazon.com: infrared thermometer

Just point it at your thermostat housing and it'll tell you what temp that is. I've dropped an ice cube on the floor and read the temp of it from a few feet away.

 

did you just install the thermostat and the overheating occurred, or was overheating occurred and you replaced the thermostat? Or neither?
Does the heater put out really really hot air when the temp gauge shows hot? That would be a clue that the coolant in the block is really really hot. Also is the radiator getting warm or hot to the touch? Indication of coolant really circulating.

 

Sorry, have to ask......is your thermostat upside down?

 

I really didn't want to say inside out,
or outside in. Is the fan shroud present?

 

What fan shroud? OP has a 1964 F100, only 1961/64 F350 223/292's with dual rear wheels came w/a fan shroud.

IMO, the OP installed the thermostat backwards.

 

I suppose the thermostat could be in upside down. However it was installed by a professional mechanic because the bolt that holds the radiator hose to engine block broke off and I needed him to re-drill it for me. I already had the thermostat and handed it to him before he started.

I'll take it apart and look.

In the meantime, is it possible that the water pump is not pumping enough water? How would I check that?

 

Make sure the gauge is correct.

 

Pro's can make the same dumb mistakes as amateurs.

1979: I bought a new Thunderbird Town Landau @ Crenshaw Motors Ford, where I worked as the back (shop) parts counterman.

During the warm up, the temp gauge needle shot up to the H and laid there like a drunken sailor.

After a week of this nonsense, I took it into the shop and had it looked at. Someone at FoMoCo's Cleveland OH engine assembly plant installed the thermostat *** backwards!

 

First, determine if it is overheating. A faulty volt. regulator behind the instrument panel can give you a false temperature reading and a false fuel level reading.

Take off the rad. cap, syphon out anti-freeze to a level 3 inches below the top of the radiator. Leave the cap off, run the engine and watch for when the thermostat is opening (some are set at 170 or 180 or 190) when it opens, check your temperature gage. Continue to run the engine with the cap off and watch the temperature gage and measure the temperature of the coolant with a thermometer. This will tell you if you have a problem with the gage.

Good luck.

 

Adding a fan shroud to non shroud equipped vehicle is not uncommon. Especially when changing engines. Constructing a shroud at the moment for a f100 truck that has transplanted 292 and larger radiator out of a later model Ford Van, wider, taller, in front of the front cross mount. I suppose I should make up a part # for it. maybe group 8146?

 

No need to construct one, or 'make up' a part number, because there's a factory shroud that'll bolt onto 1961/66 F100/350's without any mods.

D3TZ-8146-C (replaced C8TZ-8146-K) .. Fan Shroud-Use without Super Cooling Radiator / Marked on upper left corner: C8TA-8146-S or D3TA-8146-DA / Reproduced by Carpenter

Original applications: 1968/76 F100/350 360/390.

1982: I had my 1965 F100 in the shop at Crenshaw Motors Ford (at that time, was the 2nd largest parts stocking dealer on the planet) to install the newly rebuilt engine and etc.

I installed a 4 row radiator, then went upstairs to the 'bulk parts bin' locations and started taking fan shrouds from the boxes to find one that would be close.

This shroud is not close, it fit perfectly.

I've posted this info over 50 times here on FTE. Type D3TZ8146C (no spaces, no hyphens) into the search box, then you'll get lots of hits.

When the shroud was still available from Ford (it was obsoleted two years ago), I posted the MSRP & FTE member discount prices.

Several member bought them, installed them on 1961/64's with 292's.

I also installed D6DZ-8600-B .. 18" diameter 5 Blade Flex Fan, original applications: 1976/80 Granada 250 I-6 with dealer installed A/C.

 

Once again, the difficulty of fitting and using non standard parts in a fifty plus years old Ford becomes apparent. The radiator I'm using is at least 15 percent larger fin cross sectional area than what is believed to be a stock radiator for a 292 application and is also greater thickness. As a result of creating room to mount this radiator and have top tank not interfere with hood latching, the radiator rearmost surface is 4 inches away from the front edge of the fan blade. That is making use of what may or may not be the stock fan extension bracket or whatever it is called. There is no way of determining from the Ford parts manuals if a D3TZ8146C fan shroud would be long or deep enough to reach at least halfway over the fan blade and also have sufficient cross sectional area to allow air flow over the full surface area of this radiator. So I opted to design and fabricate an application specific fan shroud.
Some might say this a Kluge. Not my first, or last. I did, however, not request assistance with Ford part numbers or even mention my particular application. However don't take me wrong, I believe NumberDummy is excellent in his assistance to many many people on FTE and I thank you for that. Your understanding and assistance with the Ford system of parts is unequaled and you are truly an asset.

 

Did I hear "flex fan"?

 

Hey Bill,,,
"After a week of this nonsense, I took it into the shop and had it looked at. Someone at FoMoCo's Cleveland OH engine assembly plant installed the thermostat *** backwards! "
Could be that wonderful FoMoCo employee got his lay off notice and decided to put 2 or 3 hundred of those puppies in backward before his layoff date. Seen and heard of stuff like that being done many times. Gives you that warm and fuzzy feeling when buying a new vehicle. ;o(