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Unknown Temp Sensor

Unknown Temp Sensor

jzak

Old Time Jeeper
Posts
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Location
Pittsboro, NC
Vehicle(s)
1981 CJ5/258 4.2L I6, Tremec T-176 4-speed, Dana 300, Power Steering, Howell Throttle Body Injection System, Warn Locking Hubs, Warn Rock Crawler front/rear bumper with Tire Swing Carrier, Full Roll Cage, Pro Comp ES9000 shocks
Hello Jeepsters!

I'm pulling out a SOS on this one. I've been to Mopar, NAPA, Autozone, and none of them can get me the right coolant temp sensor. The one they say goes with my AMC 258 i6 / 4.2l AMC 258 i6 / 4.2l engine is waay too small to fit. I've attached several pictures of the old sensor below. The sensor is about a quarter in diameter. The new sensor is half that diameter.

Any help would be awesome!

Thanks!!!

Josh
 
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Part of your current TB system?
Part of the old factory emissions system?
It's not the temp gauge sending unit, as you know.
It's not pictured in the factory parts manual, for your year make and model.
For 1981-1982 non-california, there is Jeep p/n J3239065.
It should be a larger diameter for the location you show.
Without a factory picture, can't verify single threaded stud connector.
Maybe someone else with a 81-82 AMC 258 i6 / 4.2l can verify?
 
Part of your current TB system?
Part of the old factory emissions system?
It's not the temp gauge sending unit, as you know.
It's not pictured in the factory parts manual, for your year make and model.
For 1981-1982 non-california, there is Jeep p/n J3239065.
It should be a larger diameter for the location you show.
Without a factory picture, can't verify single threaded stud connector.
Maybe someone else with a 81-82 AMC 258 i6 / 4.2l can verify?

Thanks for the info! I've got two temp sensors. The other one still works, and goes to the throttle body's ECM. The one i'm trying to replace goes to the temp gauge. I'm not 100% sure, but both sensors look to be the same diameter.

By the way, could you forward a link to that p/n? I couldn't find it online.

Thanks again for the help!
 
Last edited:
Thanks for the info! I've got two temp sensors. The other one still works, and goes to the throttle body's ECM. The one i'm trying to replace goes to the temp gauge. I'm not 100% sure, but both sensors look to be the same diameter.

By the way, could you forward a link to that p/n? I couldn't find it online.

Thanks again for the help!
The temp sensor is smaller and up higher towards the back of the head.
 
The temp sensor is smaller and up higher towards the back of the head.

I haven't taken them out to check, but both of them look to be about the same size. One's towards the front on the engine next to the O2 sensor, and the other one is in the back under the throttle body.
 
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If look up by the vlave cover in the back you will see the temp sensor it points up and is in the head. That sensor you are looking at goes in the intake and I'm not sure what is. But I will see if I can find out for you.
 
If look up by the vlave cover in the back you will see the temp sensor it points up and is in the head. That sensor you are looking at goes in the intake and I'm not sure what is. But I will see if I can find out for you.

Thanks brother! I can post some extra pics of the other sensors, if that helps!
 
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It looks to be in the same position as the thermal switch for the manifold heater. Thought that started post 83 engines. Do you have an aluminium intake?
 
Difficult to tell from the picture but it looks like the manifold heater / choke sender on my 86 CJ7 .
 
So I just circumvented the whole temp sensor problem buy buying a mechanical temp gauge. Everything is working great! Thanks!
 

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