Topic: Temp sender comparison Ford vs Aftermarket

[RoyceP]

I am working on a 1968 Cougar that when driven for a few minutes pegs the temp gauge. When the temperature is checked with a Blue Point digital infra red thermometer next to the sending unit it is clearly NOT overheating. Having seen this problem before I knew exactly what to look for, and found exactly what I expected.

The OEM temp senders are C6DZ-10884-A. I got a used serviceable one from West Coast Classic Cougar.

Just for fun I connected the one from the car (no idea were it came from) to an ohm meter and checked it at 75 degree ambient temperature, then heated it with a lighter until it was at 115 degrees.

It read 190 ohms at room temperature. At 115 degrees it reads right at 50 ohms.

Oh and the aftermarket sender is large enough that an 11/16" socket won't fit properly. I assume it is some metric size hex. Edit - it appears to be 18MM.

[RoyceP]

Meanwhile a Ford sender is 300 ohms cold and 100 ohms at 115 degrees. An 11/16" deep socket fits perfectly.

[RoyceP]

Here they are side by side.

[rockhouse66]

Royce
I think these senders usually have a number stamped on them that relates to their calibration.  I know what you are saying.  There is a specific NAPA number (thank you John Murphy) that has the right calibration to put "normal" water temps in the "normal" range on the gauge.  It is amazing how water temperature concerns fade away when the gauge reads where it should.

[Bossbill]

And if you go to buy a NOS version on ebay or similar, have a few beers first. Maybe the whole 6 pack.
Brand new Ford Autolite stamped versions are over $100. Motorcraft less. They can be even less if you are lucky. The plastic ferrule is red.

[RoyceP]

The ones with the red plastic are for 390 and 428. The rest of the '68 Cougars used white, which confuses me since all of them use the same temperature gauge.

Wish I had a red one or two.

And if you go to buy a NOS version on ebay or similar, have a few beers first. Maybe the whole 6 pack.
Brand new Ford Autolite stamped versions are over $100. Motorcraft less. They can be even less if you are lucky. The plastic ferrule is red.

[Bob Gaines]

I am working on a 1968 Cougar that when driven for a few minutes pegs the temp gauge. When the temperature is checked with a Blue Point digital infra red thermometer next to the sending unit it is clearly NOT overheating. Having seen this problem before I knew exactly what to look for, and found exactly what I expected.

The OEM temp senders are C6DZ-10884-A. I got a used serviceable one from West Coast Classic Cougar.

Just for fun I connected the one from the car (no idea were it came from) to an ohm meter and checked it at 75 degree ambient temperature, then heated it with a lighter until it was at 115 degrees.

It read 190 ohms at room temperature. At 115 degrees it reads right at 50 ohms.

Oh and the aftermarket sender is large enough that an 11/16" socket won't fit properly. I assume it is some metric size hex. Edit - it appears to be 18MM.

Most likely a typo (been there done that)but C6DZ-A is for 6cyl and C6DZ-B is for V8 according to the MPC. There have been various discussions like this before.  http://www.concoursmustang.com/forum/index.php?topic=21427.0 There are other recent ones that I could not find but maybe others can.here is another on the SAAC Forum. http://www.saacforum.com/index.php?topic=9140.0

[Bob Gaines]

The ones with the red plastic are for 390 and 428. The rest of the '68 Cougars used white, which confuses me since all of them use the same temperature gauge.

Wish I had a red one or two.

I don't know about Cougar but 66 and 67 and most likely 68 smallblock Mustang/Shelby used the red insulator C6DZ-B according to the MPC which aligns with observations that I have had.

[midlife]

Meanwhile a Ford sender is 300 ohms cold and 100 ohms at 115 degrees. An 11/16" deep socket fits perfectly.

I thought they ranged from 13 (hot) to 73  (cold) ohms.  That's what all Ford gauge sending units are supposed to range circa early 60's through mid 70's. 

[RoyceP]

The Lincoln Mercury MPC calls out the white one for 289 and 302 Cougars in 1968 and 351W for 1969. Mine is April 1969 Revision so it doesn’t cover any other year Cougars. The red one is listed for 390-2V or 4V and 428CJ.

I don't know about Cougar but 66 and 67 and most likely 68 smallblock Mustang/Shelby used the red insulator C6DZ-B according to the MPC which aligns with observations that I have had.

[Bob Gaines]

The Lincoln Mercury MPC calls out the white one for 289 and 302 Cougars in 1968 and 351W for 1969. Mine is April 1969 Revision so it doesn’t cover any other year Cougars. The red one is listed for 390-2V or 4V and 428CJ.

The 69 351 W for a Mustang application has a green insulator.

[Mike_B_SVT]

The 69 351 W for a Mustang application has a green insulator.

I seem to recall reading that the Boss 302's used a green insulator as well, but I have no docs to back that up.

[RoyceP]

The MPC shows C9WY 10884-A (SW888) for 351W only.

I seem to recall reading that the Boss 302's used a green insulator as well, but I have no docs to back that up.

[KevinK]

I thought they ranged from 13 (hot) to 73  (cold) ohms.  That's what all Ford gauge sending units are supposed to range circa early 60's through mid 70's.

I agree with Midlife.

I was having a similar discussion with a friend on his 86 and 87 2.3L. Eventually he looked it up in the Ford manual to find it stated 74 ohms at Cold mark and 9.7 Ohms Hot mark on the gauge.  Picture shows the sensor connected.  Gauges have not really changed since the 6 volt days until they went digital.

On another note, he measured 206 ohms and 220 ohms at 80f on his 2 sensors in question.  It seems there may be a difference in the resistance readings with the sensor in the circuit and out of the circuit.

[RoyceP]

I now own NOS originals with both the red and white plastic. Both read 300 ohms at room temperature, same as the used one from WCCC.

In boiling water the red one tested at 10 ohms. I did not test the white one but should.

I thought they ranged from 13 (hot) to 73  (cold) ohms.  That's what all Ford gauge sending units are supposed to range circa early 60's through mid 70's.