72 FJ40 Coolant Temp Sender Unit (Short vs. Long) (1 Viewer)

[funk49]

I've got an issue that I could really use some help with.

I"m at the tailend of an F engine rebuild on my 72 FJ40 and the guy who is doing the work said I needed a replacement for the Coolant Temp Sender unit. I got an OEM one from Cool Cruisers but it's the long shaft. The mechanic told me the short shaft one is for the "module" (whatever that means, maybe the emissions unit) and the I need. He said it appears that the longer sensor is for the dash gauge.

I can't find the shorter shaft sensor anywhere, only the long ones but @ToyotaMatt at vintageteqparts.com has a longer union nut they offer which would appear to allow the longer sensor to work. Does anyone have any thoughts on whether this would work (mechanic thinks it may not because the resistance could be different)? I've got emails out to vintageteq as well as a call into @65swb45 but haven't heard anything yet.

This is a previous thread where it's discussed but this appears to be for the dash gauge sender/sensor:

Vendor - NOS OEM Water Coolant Temperature Gauge Sending Unit Sensor 83420-20010 Fits 1958-1972 FJ40 Fj55 FJ45 FJ25. ALSO < NEW Chrome Sensor Union Top Shelf

NOS OEM Water Coolant Temperature Gauge Sending Unit Sensor 83420-20010 Fits 1958-1972 FJ40 Fj55 FJ45 FJ25 $88 Available for a separate ADD ON purchase is : The Rising Sun Mechanical 's Finest Hour Reproduction End Product $29...

forum.ih8mud.com

If anyone has a shorter one available, please send me a PM because I desperately need it.

 

[ToyotaMatt]

I've got an issue that I could really use some help with.

I"m at the tailend of an F engine rebuild on my 72 FJ40 and the guy who is doing the work said I needed a replacement for the Coolant Temp Sender unit. I got an OEM one from Cool Cruisers but it's the long shaft. The mechanic told me the short shaft one is for the "module" (whatever that means, maybe the emissions unit) and the I need. He said it appears that the longer sensor is for the dash gauge.

I can't find the shorter shaft sensor anywhere, only the long ones but @ToyotaMatt at vintageteqparts.com has a longer union nut they offer which would appear to allow the longer sensor to work. Does anyone have any thoughts on whether this would work (mechanic thinks it may not because the resistance could be different)? I've got emails out to vintageteq as well as a call into @65swb45 but haven't heard anything yet.

This is a previous thread where it's discussed but this appears to be for the dash gauge sender/sensor:

Vendor - NOS OEM Water Coolant Temperature Gauge Sending Unit Sensor 83420-20010 Fits 1958-1972 FJ40 Fj55 FJ45 FJ25. ALSO < NEW Chrome Sensor Union Top Shelf

NOS OEM Water Coolant Temperature Gauge Sending Unit Sensor 83420-20010 Fits 1958-1972 FJ40 Fj55 FJ45 FJ25 $88 Available for a separate ADD ON purchase is : The Rising Sun Mechanical 's Finest Hour Reproduction End Product $29...

forum.ih8mud.com

If anyone has a shorter one available, please send me a PM because I desperately need it.

do you have 2 coolant sensors by chance ?

tall one in the rear on the head near the hose bib.

and


a short one dead center behind the carburetor ?
mayber a RED TIP on top ?

 

[65swb45]

Rob

I’m sorry I couldn’t get back to you. Things got sideways on me Thursday, big time. Just getting back on track now.
You should only need the one TALL sender and the matching TALL union to run your original guage. The short sender has a different ohms scale and will not work with the earlier guage.
Since you already have the tall sender, it’s reasonable to assume you just need the union. That is too small of a sale to meet my minimum order. I’d trade you one for a six pack of premium IPA at my doorstep. Otherwise @ToyotaMatt is your best bet.

 

[funk49]

do you have 2 coolant sensors by chance ?

tall one in the rear on the head near the hose bib.

and


a short one dead center behind the carburetor ?
mayber a RED TIP on top ?

I do have two sensors, one for the gauge and one for the "module" (again, I don't know what that means). The short shaft one that I need appears to be next to the carb and the gauge sensor is further back on the head, closer to the firewall. I need one that has the same "button" on top but shorter shaft, unless you guys tell me that I can use a taller union nut and just use the sensor I already purchased. @65swb45, feel free to chime in with whatever info you may have, it's always welcomed.

I've enclosed a pic so you can see which one it is. It looks like the connector on the top broke off. Thanks for your help Matt!

 

[funk49]

Rob

I’m sorry I couldn’t get back to you. Things got sideways on me Thursday, big time. Just getting back on track now.
You should only need the one TALL sender and the matching TALL union to run your original guage. The short sender has a different ohms scale and will not work with the earlier guage.
Since you already have the tall sender, it’s reasonable to assume you just need the union. That is too small of a sale to meet my minimum order. I’d trade you one for a six pack of premium IPA at my doorstep. Otherwise @ToyotaMatt is your best bet.

Thanks Mark, no worries at all and I do appreciate they help. The short sender unit is not the one for gauge but for the "module" (unclear what this means). I just replied to @ToyotaMatt about what I have and wondering if I can use the tall shaft with the tall union nut instead of the short one that it has.

The short one looks like what they have a SOR but that one doesn't have the button on top, it has the flange coming off the side. I'm at the very end of my build and am dying to get this issue resolved so I can get my truck back. Thanks again!

 

[65swb45]

You don’t NEED either to drive the truck; you just need to seal the hole(s). Granted, if you had the correct part, you’d only have to do it once.
I know you have a carburetor on your truck so I’m at a loss what else you’d need a “sensor” for.

 

[65swb45]

I have a box with over 60 used terminals , including some of the round connector ones.

 

[ToyotaMatt]

Thanks Mark, no worries at all and I do appreciate they help. The short sender unit is not the one for gauge but for the "module" (unclear what this means). I just replied to @ToyotaMatt about what I have and wondering if I can use the tall shaft with the tall union nut instead of the short one that it has.

The short one looks like what they have a SOR but that one doesn't have the button on top, it has the flange coming off the side. I'm at the very end of my build and am dying to get this issue resolved so I can get my truck back. Thanks again!

the smaller union behind the center of the Carburetor is called a Thermo-Sensor it tells that module how hot your engine oil is ..

this is a first generation very basic and primitive SMOG / Emissions part that fed a Signal based on the coolant TEMP. to that module you refer to ....

- is this short THERMO-Sensor or its short UNION leaking Coolant ?

 

[funk49]

the smaller union behind the center of the Carburetor is called a Thermo-Sensor it tells that module how hot your engine oil is ..

this is a first generation very basic and primitive SMOG / Emissions part that fed a Signal based on the coolant TEMP. to that module you refer to ....

- is this short THERMO-Sensor or its short UNION leaking Coolant ?

Thanks for the info @ToyotaMatt, I'm not sure on this and will be able to find out on Monday. If it is leaking from the top (looks like that button thing has maybe broken off), could it just be plugged like @65swb45 said and just be done with this issue? I'm in CA and don't have to worry about smog requirements for this truck.

 

[65swb45]

Yes, and Matt sells the plug too.