Temperature Sending Unit

Can anyone tell me if this (The arrow beside distributor) is my temp. sending unit on my 304 cj5? I have tried chasing the wires from the gauge with no luck, but I believe this is it.

Also, if I remove this in order to install a new gauge, will I have a coolant spill?

 

That is the approximate location of the sending unit.

You may lose a little coolant, might want to drain just a bit before pulling it out.

Looks like this:

 

Thanks. What is the easiet way to drain it (cleanest)? My fuel or temperature gauges aren't working now and I am going to add aftermarket gauges and just leave the broken ones there.

I bought a SunPro temp. gauge that came with another sender but the fitting doesn't look like it will fit the jeep. I think I am going to have to get an adapter kit also.

I guess I will order a Autometer fuel gauge at AutoZone with 73-10 ohm readings.

 

You might get away with just having the new one ready to go in and pack some absorbent towels around it before pulling it...then plug the new one in right away...you might not lose too much fluid. I've done that before without a lot of loss. Otherwise just open the drain-**** on the radiator and drain a little fluid, the block should drain down some.

Can't comment on your other items.

(ha ha...I just noticed that my post was automatically edited for a bad word...without intending to post a bad word)

 

I have done this with a sender at the botom of the block too. Have the new one ready to go in and easily reachable. remove the old one and block the hole with your finger or thumb. Pick up the new on and plug it in while removing your thumb. You will loose a little bit of coolant but it won't make a big mess. Of course you will want to make sure the engine is cool before you try this. R)

 

why wait til the engine is cold? that take all the fun and conquest out of the project. If you want a real change you change it while the temp is still warm. trust me it is a LOT more fun.

 

put the shop vac on the roof....hose taped to filler neck...turn on vac...remove sender and listen to the gurgling of air going INTO the hole left by the sender....put new sender in and your done very little if any lost coolant....oh yeah don't use mommas vac. Ive used this trick on many different fluid filled things (hydraulic tank on equipment, swimming pool filter and others)and it does work

 

Heh. It should work, but I wouldn't think to try it.

 

What's wrong with draining some coolant? Take your time and don't cross-thread anything and you will be much better off then having anti-freeze running all over the ground.

 

What I am wondering is have you done a thorough test on your original temp - fuel gauges to determine that they are in deed both bad?

 

I am actually in the process of trying to test the original gauges now. I don't have much time to work on it other than weekends, but I got some electrical testers yesterday just for this purpose. However, when I looked under the dash, the previous owner had put 12V to both the fuel and temp gauge, so I am guessing the temp gauge is fried.

Would the fuel hand work even if the temp does not? Would I have to unhook the temp gauge in order to get the fuel gauge working? The previous owner installed a brand new tank and sender, painless wiring harness, etc. along with many new parts. I did try to hook up just 12V to the fuel gauge and ground the sender connection point but the hand didn't move. If I remember right, the temp gauge is stuck on H all the time and the fuel gauge is stuck on F, so both gauges are pegging to the right. Could this be a bad ground?

 

There's a good thread on the cluster gauges on the early forum now: http://www.earlycj5.com/forums/showthread.php?t=64523

AFAIK the intermediate gauges have the same internal voltage regulator that the early gauges have. You can see that teh CVR (constnt voltage regulator) is internal to the fuel gauge, and it that's toast, it will affect both the fuel and temperature gauges.

I'd suggest you put the year and equipment of your Jeep in your sig. I think it's a '75 from memory, but I'm not sure. I recall I pointed you to the '76 manual for another problem? The '72 manual at www.trailforge.com would also be helpful re gauge problems. Realize that the wiring harness is completely different on a '72 compared to a '75, but the components will be the same.

With electrical stuff, you just need to be systematic and consider each circuit, one at a time. I presume you have a multimeter.

hth!

 

hahaha thats awesome ill try it next time!

 

Alright. I was wrong about where the hands are stuck. The original fuel hand is on E (which is to the right) and the heat hand is on C (Also to the right). I have tried the past couple days to get a chance to actually see if they are working. Based on these readings, I think it's possible that the gauges just aren't getting power at all or the wires from the sender are bad.

Hopefully I can get these things working this weekend. IF so, I just ordered a replacement fuel and heat gauge from the internet, that I will sell cheap to anyone in need. It is not the entire cluster, just the two hands to use as replacement inside of the original cluster.

 

Please note that the fuel gauge has a grounding spot in the middle of the mounting studs. It grounds to the speedo housing and then the speedo assy is grounded to the dash panel and then grounds to the tub and then grounds to frame and then grounds to engine and then grounds to neg term of battery. Lottsa places to loose ground. A seperate ground wire from the engine directly to one of the four speedo mounting studs is recommended. To repair the ground from the gas gauge to the speedo housing, you have to remove the speedo housing from the innerds.

 

Well, I finally got my fuel and temperature gauge working this weekend. However, this created another issue.

I changed the entire cluster for an aftermarket set, which was given to me when I purchased the jeep. The gauges on the original were bad for sure. Now both gauges work buy my speedometer hand now bounces pretty bad. With the original gauge, it was rock solid but now it bounces almost 10mph while driving. I lubed the end before installing it, but it didn't help. Do I need to change the whole speedometer cable now?

 

Seems to me that you have good gauges and a good speedo head, but not together. Why don't you take the good parts and put them together?

 

You know, I really thought about that, but I figured I might tear them all up by trying that! I actually took the old speedo apart, to see how the 2 small gauges came out b/c I was going to attempt it. It wasn't too hard to get them out, I just backed out of trying it.

 

just dont use mommas vac..unless you are a glutton for punishment....it could and has sucked oil and water makes kind of a mess in the hose but the jeep dosent have rugs and the floor in the shop dosent mind a little oil......I used this trick on a cat 320 excavator to hold 45 gals or so of hydralic oil in while changing the main pump the boss was happy as we had just changed the oil before the pump puked and he didnt want to buy more...bosses are all the same