Oil Presure & Temp Sending units wrong size threads

[gerth21]

Hey guys, I searched the site and was not able to find an answer to this. I went to replace my Oil and Temp sending units on Saturday and both units the threads were to large for my 83 CJ7 AMC 258 i6 / 4.2l . I went back to Napa where I got them from and they said according to their computer these were the proper units. I replaced all my gauges with new ones a couple month ago when I replaced my dash and these two still do not work right so I figured I would replace the sending units.

Anyone had this problem and know the right parts for this.

 

[Jimbos76cj]

Napa is great if you know exactly what you want.. ask for any thing that differents from thier computer and they are dumbfounded. is it a metric thread? You should be able to find an adapter to go from the smaller to the bigger.

 

[mtnwhlr]

I wouldn't wast your time trying to find adapters. If they don't fit they are the wrong ones take them back and order some from someone who deals in Jeeps or you might try Rockauto I have had good luck with them.

 

[IOPort51]

I must ask a silly question: did you remove the old and try the new??

Sometimes 1/4" pipe threads look bigger or smaller than they are.

that said can you give up pictures of what you have , both on the engine block and the new sending units??

 

[gerth21]

I must ask a silly question: did you remove the old and try the new??

Sometimes 1/4" pipe threads look bigger or smaller than they are.

that said can you give up pictures of what you have , both on the engine block and the new sending units??

Not a silly question, I have to ask questions like this at work all the time. I did take off the old unit and try to install the new one. I then put them side by side and it was obvious they were different sizes. I already returned the new ones so I cant take a picture. I did notice that the existing one the thread was smaller that the nut to tighten it where the new one was almost the same size.

 

[bondo258]

"the nut to tighten it"? NPT don't reguire locknuts.

Even if that's not what you meant to say, it sounds like you're dealing with a previous owners modifications.

Maybe the original hole in the block was stripped out.

Maybe he/she replaced the adapter with one that was the wrong size and tapped it out. Then to "make it work" threw in a T'eed combo switch/ sender from something else.

O.P. senders and Switches had decades of interchangeability, even through the Nineties, as far as threads go. Hard one to FUBAR, now the function can be a different story...

NAPA 6603 and 6613 are proper for your CJ. Are these what you purchased? If not that could be a problem.

I always try finding part numbers before I go. Ideally, you and the parts guy find the same number. Sometimes you are the only one to find the number needed.

 

[gerth21]

"the nut to tighten it"? NPT don't reguire locknuts.

Even if that's not what you meant to say, it sounds like you're dealing with a previous owners modifications.

Maybe the original hole in the block was stripped out.

Maybe he/she replaced the adapter with one that was the wrong size and tapped it out. Then to "make it work" threw in a T'eed combo switch/ sender from something else.

O.P. senders and Switches had decades of interchangeability, even through the Nineties, as far as threads go. Hard one to FUBAR, now the function can be a different story...

I always try finding part numbers before I go. Ideally, you and the parts guy find the same number. Sometimes you are the only one to find the number needed.

I have found out with everything I have done to this Jeep that the PO has done a lot of stuff. It may be time to do a full restore from scratch.
NAPA 6603 and 6613 are proper for your CJ. Are these what you purchased? If not that could be a problem.

 

[bondo258]

Sometimes the jerks at the "distribution center" mess up what comes from what bin, and goes into what box, as well.

But...

The fact that both are not fitting makes me think that the adapter tee is wrong. Hardware stores usually carry these along with whatever else you want in the plumbing dept. See what you need there, if this is the case.

Some (all?) Marine NPT fittings are too small on the female side. It's an odd taper or the threads get warped when coated. Not sure which it is. The male sender end gets jacked, as the steel is harder on the fitting.

Marine stuff is usually bright yellow zinc galvanized steel. if you have this stuff, just replace with street brass NPT fittings.

Yes, Napa stuff has fit in the past. The old sender was 9/16ths wrench to remove and 15mm to install new one. This is common with most replacements. The switch may have been the same way, I used crescent wrench and don't recall.

Happy Hunting.