Heating up at idle.....

F

Ford Freak

Well-known member
Hey guys! My '56 Club Sedan has a 351C in it. While idling it climbs to 200-210. However, when I point my laser temp gun at the t-stat houising it reads 170. The radiator is 20 degrees cooler at the bottom than top, so the coolant is circulating. The temp gauge is a new Autometer electric unit. Not a big fan of electric temp gauge's, but that's what it came with it came with. So, is the t-stat housing the best place to get the most accurate reading? Which reading would you all go by? Thanks in advance! F F
 
oldbugger said:
If it don't go over 210 and your running a pressurized system your probably ok.
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Well, I shut it off when it hits 210. It is pressurized. Champion aluminum 3 row radiator made for the car, w/a 16 lb. cap. I am going to go to a 19" 6 blade fan (it has a 16" 5 blade on it now) and one of those 3" wide, 2/3rds around universal shrouds. I just wondered how accurate those infa-red temp guns are, & if the t-stat housing is the best place to point it. F F
 
The sending unit can not have any sealer on the threads. If it does it will read high.

Does the car start to stumble when it may be heating up (listen tot he tail pipe....)?

Ya know your vacuum advance unit control timing at idle, and at cruise..... Just a thought.
 
My cheap Amazon infrared temp gun read within 1/10 of a degree with a technician’s Fluke meter. One time I put 3 inexpensive instant meat thermometers in a pot of soup, they and the infrared gun were all within 3-4 degrees. Unless you’re in Denver, 212 is boiling water, and you can test the gun. I’d trust it over a gauge.

The housing is the best spot as far as I’m concerned, and that’s the location the tstat sees.
 
All good stuff to know. The sender unit has teflon tape on it. I will remove that tomorrow. The engine does not have the vacuum advance hooked up. Only mechanical advance. My temp gun is a cheepie from Harbor Freight. Probably the same as you have. Glad to hear that they are very accurate, because if they weren't, there would be no point in me having one in my toolbox! Thanks guys! F F
 
On things that are electrical I use aluminum anti seize compound. Same as I use on plugs and stainless. Seems to help the seal, and conducts electricity.
 
The 351C had a unique t-stat. It has a bronze/brass fitting on the bottom of the stat that moves down and closes off a "bypass" that is cast in the block. Make sure you have the correct t-stat or do the mod that many folks do. That is to braze in a penny/copper plug to close off the bypass. Doing that allows you to use any T-stat. It was intended to speed warming up the coolant quicker.
 
Ford blue blood said:
The 351C had a unique t-stat. It has a bronze/brass fitting on the bottom of the stat that moves down and closes off a "bypass" that is cast in the block. Make sure you have the correct t-stat or do the mod that many folks do. That is to braze in a penny/copper plug to close off the bypass. Doing that allows you to use any T-stat. It was intended to speed warming up the coolant quicker.
Click to expand...

Yes, mine is blocked off, & I have a regular 180 t-stat in it. Good info for those unaware of the unique 351C t-stat setup. Thanks! F F
 
The 351C also has a what looks like a washer under the
T-stat.
 

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56sedandelivery said:
The 351C also has a what looks like a washer under the
T-stat.
Click to expand...
I removed the brass part & replaced it with an aluminum "block off" plate that I got from West coast Classic Couger. It allows you to use a regular, everyday t-stat. Very popular modification with the guys on the vintage Mustang forums. Thanks for the pic! F F
 
Now we're getting somewhere! I removed the temp sending unit, & peeled off the teflon tape. I re-installed it with Never Seize. It sealed and it must be getting a good ground now, as the gauge is reading differently. While idling in my garage it got to 180, stayed there for about 5 min., then slowly crept up to 195-200, which I am ok with. Still, my infa red thermometer said 165 when pointed at the thermostat housing, when gauge said 195. It matched the gauge up to 140, but not when the gauge read higher. So, I got a new thermometer from Harbor Freight. This new one reads the same as the gauge in the car. I still have a new fan & shroud coming, which i will install this weekend. Thanks to all who responded! F F
 
OK, I just did that on my 57, and have not posted my pictures or any text on the project yet.
 
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