Temp sender for factory gauge ?

[George White]

I basically built a 306ci motor roughly 375hp, did away with the original sender in the pipe/hose intake spacer and running the coolant temp sender directly into the aluminum intake 3/8 pipe thread for a ’66 mustang 289. This is the 2nd sender, 1st one did not work at all-this one pegs the whole gauge after warm at typically 187-197deg f. I’m assuming their is a sender that would be the right ohms and thread to correspond with the factory gauge and give a ballpark reading ? Thanks George

[Sean Johnson]

I used the factory sender for an Alpine or Tiger plugged into my F4B Edelbrock intake… Not the thermostat housing. It has been providing me with accurate readings for some 30 years now…

[Sean Johnson]

Happy to supply a Pic if you want…

[Michael Hartman and Donna Bissey]

I think I know a VDO temperature sender that should work reasonably well. I did some research for Dan Richardson to find temperature senders that were 1/8 NPT. One sender I tested was the VDO 323-095. By tested, I mean I heated up a pot of water across various temperatures and measured the resistance of the sender. My conclusions about the VDO 323-095 were:

The VDO sender resistances are lower than the Temp gauge expects. That means the temp gauge will read higher than the actual coolant temperature. The VDO sender will result in the Temp gauge reading about 9 degrees higher than the actual coolant temperature at around normal operating temperature. E.g. When the coolant is 185 degrees, the temp gauge will read around 193 degrees.

I also had some thoughts on adding a resistor in series to get the temperature gauge readings more accurate within the normal operating temperature range, but maybe it is sufficient to know the temperature value is always off by a little bit.

I checked the VDO web site and they are indicating the VDO 323-801-001-007N is 3/8 NPT and it has the same resistance range values as the 323-095 sender that I tested. I expect the only difference is the size – 1/8 vs 3/8 NPT. It appears that the VDO 323-801-001-007N part number is also VDO part number 323-094.

Mike

[George White]

Thanks mike for the Vdo part number-i will try that as i have tried a new replacement intermotor #52720 which turns out is the late model ohm sender-apparently they don’t make the #52700 original early model one anymore. If it pegs the gauge again at 190 i’ll just have to put an adjustable resistor inline and dial it in that way

[Michael Hartman and Donna Bissey]

Hi George,

Your comment about early and late senders got me wondering. I’m an Alpine guy … the same temperature sender was used for Alpines from series 3 to 5. I am assuming the Tigers used the same temperature gauges as the series 4 & 5 Alpines. Those work based on thermal heating. If the same temperature gauges were used on Tigers, the VDO part should work as I described. You also need to have a voltage regulator in place. An original voltage regulator cycles the power on and off to generate an average power that is equivalent to a constant 10V. Or use a use a modern solid state voltage regulator that puts out a constant 10V DC.

Mike

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