I picked up & installed a new temperature sending unit from the local parts store for about 8 bucks. My gauge now reads at the 3rd hash mark right befor the "H" when driving 40 mph on a day with temps in the upper 70's. Seems to be reading a bit on the high side to me, but the truck's running fine with no signs of running hot.
The same thing happened when I installed one in my '66 Tbird last winter. Are these units off? Any ideas on an easy way to verify operating temperature?

 

To me its odd; but possible; two bad senser switches; but not likely; I would check the voltage reading you get from the back side of the dash bezel; as well as any good connuity between sending unit and your dash. I would even switch out the temp gauage cluster on the bezel to trouble shoot the reading as well ( if you had a spare one).
But if truck doesn't run hot; I would also possible switch out the thermostate to a lower degree!
Just my thoughs.

 

I wonder if my putting teflon tape on the threads has anything to do with it.

 

what temp t/stat are you running ???

- cs65

 

Possibly. Borrow an infrared thermometer or check with a mechanical gauge. These gauges were not that accurate to begin with. I keep a cheap set of SunPro mechanical gauges for this purpose and breaking in new engines. I wouldn't go changing anything till you know you actually have a problem.

 

I hear that. I personally think the problem is the sending unit is not cmpatible with the original gauges. I will get another modern gauge to verify the actual temp, but I would like to retain the original gauges functionally. As it is, there isn't enough room on the stock gauge to give me much warning if there is overheating.

 

Well, I swapped in a few sending units I found at the salvage yard. The new one I swapped out was reading @ 3/4 of the way to "H". The first salvaged one I swapped in read @ 5/8 of the way to "H". The second salvaged one I swapped in read @ dead center, or 1/2 way to "H". Go figure.

 

C3AZ-10884-A .. Temperature Sending Unit (Motorcraft SW344).

Applications: 1963/64 352/390/406/427 Galaxie/Mercury & 1963/64 390 Thunderbird / 1965 F100/350 352 & 1966 F100/350 352 before serial number 751,000.
--------------------------------------------------------------------------------------------------------------------------------------------------------
C5DZ-10884-A .. Temperature Sending Unit (Motorcraft SW-427).

Applications that apply in this case: 1965 390 Thunderbird / 1966 390/428 Thunderbird before production date 9/1/1965.
-------------------------------------------------------------------------------------------------------------------
C6DZ-10884-B .. Temperature Sending Unit (Motorcraft SW-552).

Applications that apply in this case: 1966 F100/350 352 from serial number 751,000 / 1967 F100/350 352 / 1966 390/428 Thunderbird from production date 9/1/1965 / 1967/69 390/428/429 Thunderbird.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1964/66 Thunderbird: Do not believe the readings of the 4 gauges...note where the needles rest when the ignition key is in the off position.

Depending on certain factors, the needles of all 4 gauges may rest below the markings. It does...for sure...on the oil pressure gauge.

Owners back then complained about (supposed) low oil pressure on these cars. This was caused by the oil pressure gauge needle, because it rested well below the mark when the key was in the off position.

In 1966, Ford came out with a new 'dealer installed' oil pressure sending unit for these cars (C6SZ-9278-A), gave a FALSE reading (I kid you not) to end customer complaints about (so called) low oil pressure.

I once owned a 1966 428 T-Bird Town Landau, installed one a these senders to see what happened. The needle went almost to the high end of the oil pressure reading...almost an inch higher than it read with the other sending unit.

If you want accurate water temperature, install an aftermarket direct reading temperature gauge.

As you can see, Ford used different temp sending units and who the he!! knows what sender is in these vehicles today.

 

The temp sender even when new none of them read the same!! So don't worry they only had to be in a certain OHM range and this is why ford made the "normal: range so large to compensate. I would just run it and not worry.

 

Thanks, ND. I'm sure the O'Reilly parts guys don't have access to that kind of info, or a wide enough selection of sending units to deal with it.

I hear you. I just wanted to get enough range to get a fair warning if I start to overheat.

 

Bill, is the temp unit which you listed below still available? Since my 65' falls under #751.000, I'd like to get 1or2 to keep in stock just in case.

While we are on the subject of sending units, if you recall the round speedo I have with all for gages in the same unit that the po special orderd, I would like to get a new oil sending unit for that, also to keep in stock in case I should need it. As you know, my F-100 is a 65' and has the date stamped on the back of the speedp but there are no # stampings on the oil sending unit. The sending unit I am talking about is that funny looking dome shaped thing with a nut on top for the wire. Are all those sending units the same for all yrs or is there one specific to the 65' gage? I have the truck partually taken apart and can take pics of the speedo unit front and back. Well, a friend of mine said he can use his cell phone. I don't have a camera and I'm too poor to get a phone with a camera. ;o(
Thank you Bill, let me know.
Fritz

C3AZ-10884-A .. Temperature Sending Unit (Motorcraft SW344).

Applications: 1963/64 352/390/406/427 Galaxie/Mercury & 1963/64 390 Thunderbird / 1965 F100/350 352 & 1966 F100/350 352 before serial number 751,000

 

Do you want the phony baloney oil pressure sending unit (C6SZ-9278-A) that dealers installed in 1964/66 Bird's (will fit all other FE's and etc), or the real one?

E4ZZ-9278-A (replaced C9ZZ-9278-A, C7ZZ-9278-A, B7T-9278-A) .. Oil Pressure Sending Unit-Use with oil pressure gauge (Motorcraft SW-1547B) / Available from Ford.

MSRP: $34.26 // FTE sponsor PARTSGUYED.COM price: $20.56 (Horizon Ford in Seattle).

Since this little charmer was used from 1957 thru 1996 on a vast number of vehicles, you can buy it locally at an autoparts store...mebbe for less than the 20 buck price...and pay no shipping charges from WA
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
C3AZ-10884-A .. Temperature Sending Unit (Motorcraft SW-334) / Obsolete as the dodo bird.

SOEBY MOTOR CO. in Walhalla ND has ONE = 701-549-3711 (This mom & pop dealer closes for lunch!).

GREEN SALES CO. in Cincinnati OH has ONE = 800-543-4959.

ANTIQUE AUTO SUPPLY in Arlington TX has ONE = 817-275-2381.

B & L FORD in Ashland PA has TWO = 570-875-4417.

MILLER OBSOLETE PARTS in Binghamton NY has TWO = 607-722-5371.

WESLEY OBSOLETE PARTS in Liberty KY has TEN = 606-787-5293 (If the lady that inherited the biz answers the phone, it's a miracle! Leave a message, she'll call you back, hopefully before Xmas).

 

Thank you Bill. You do bring up a couple questions. Why do you say "the phony baloney oil pressure sending unit (C6SZ-9278-A) that dealers installed in 1964/66 Bird's"? Are these unit garbage and why? Give out bad readings maybe. I will pick up a SW1547B. Will check local places first before ordering. Still, why do you say phony baloney?

I'll order the SW334 right away.

 

The needles on the dash oil pressure gauges of 1964/66 Thunderchickens rested well below the line when the key was off, so when the engines were started, the oil pressure reading barely reached the half way mark of the guage.

1000's of customers complained of (supposed) low oil pressure, but they didn't take into consideration where the needle rested when the key was off.

So, what Ford did was...they came out with a "campaign" dealer installed sending unit (C6SZ-9278-A).

It was a phony baloney, because it raised the oil pressure reading on the gauge (at least an inch), making those 1000's of customers happy as clams.

See post #8 for more info on this sender.

I can picture the next chapter of this sender. A member will read this post, is selling a vehicle with next to no oil pressure, will want one a these senders....so the potential buyer will be as happy as a clam.

'Course that won't stop the smoking and knocking like a bill collector, but a combo of STP, 90wt gearlube, sawdust and banana peels work wonders...for a short time.

 

"combo of STP, 90wt gearlube, sawdust and banana peels"

HAAAAAAAAAA,,, Funny
Now Bill, I've heard of the first 3 being used, but banana peels??? Interesting idea. You would think the grunting would give it away. ;o)