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  Topic Review (Newest First)
12-19-2019 10:39 PM
BagusJeep
Quote:
Originally Posted by John Strenk View Post

Here is the 4.0 thermostat housing. This one is for a 97-06 Jeep Wrangler.



https://www.quadratec.com/products/51209_1008.htm

As you can see, it has a port just perfect for the temperature sensor and it bolts right onto a 258 block.
I did this on my J20 as a temporary fix because the gauge electrics on teh cluster are proving troublesome and time consuming. An Autometer water gauge just screwed right in there and I can use it until my cluster is running again. Found the old one was rusted to heck and had epoxy inside from a previous leak.

Bottom picture is of CJ7 Puthijeep which had previously had the same setup but with an electrical sender before I got the fuel and temp gauges working in the speedo, thanks to John's help.

If you have not checked your thermostat housing recently, you may find it is rotted to heck.
12-13-2019 09:16 PM
John Strenk Temp. gauge calibration:
C (cold)........................ 130 degrees--73 ohms
Beginning of band.......... 171 degrees--36 ohms
Top of band.................. 242 degrees--13 ohms
H (hot).......................... 270 degrees---9 ohms
12-13-2019 01:19 PM
steve801 Do you happen to know the resistance of the stock CJ sensor so I can match a gauge accordingly?
12-13-2019 12:02 PM
John Strenk sometimes...
Check the specifications of the meter. it list the designed resistance range.
12-13-2019 06:32 AM
steve801 Thank you all for your input. My OEM temp gauge has failed so i thought a mechanical replacement would be easier than pulling the cluster (again). So, as I recall from Johns previous posts on the fuel gauge...would a new stand alone electric temp gauge have to be matched (resistance) to the sensor?? I.E. Can i use the stock sensor with an aftermarket electric gauge?
12-12-2019 01:13 PM
MrPeter63 The 4.0 housing would be your best bet, or like i said, depending on your intake there should be a larger port some where on it. There is also should be a coolant port under your carb on the side towards the back of the intake where the Temp sensor is for the intake heater. If your intake heater is still hooked up you can always T off of it and screw both sensors into each end of the T. They also make Temp sensor adapters for Radiator hoses and heater hoses, but wouldn't be my thing, I'm sure they work fine but kind of look half assly in my opinion....
12-12-2019 12:33 PM
StoneTower Those gauges work just like a mechanical air pressure gauge. The oil (or fluid in the case of the temperature gauge) pushes against plunger attached to a spring in the gauge and that causes the needle to move. With mechanical temperature gauges, you cannot generally shorten or replace the tubing. It is a sealed unit and if you cut it , you have to buy a new gauge. The mechanical oil pressure gauge is just a thin tube that hooks into an oil passage in the motor and you can cut it your desired length.
12-12-2019 12:28 PM
John Strenk A capillary tube has a very small passage inside the tube, So if you used a a set of diagonal cutters on it you are basically crimping it and the cut would just look like a thin wire.

You would have to use a cutoff wheel to actually see the passage.
12-12-2019 12:16 PM
TerryHowe
Quote:
Originally Posted by John Strenk View Post
I think that copper wire is actually a copper tube that contains a fluid that pushed the meter movement as it expands.
That is why the sensor end has to be so big and have a big fitting to hold it in place.
Well last one I was messing with was definitely a wire because I cut it to find out. It probably depends on how much you spend on the gauge.
12-12-2019 12:16 PM
StoneTower I was so happy when I got rid of my Autometer mechanical water temp and oil pressure gauges that the previous owner installed. The oil pressure gauge used to drip a few drops of oil every once in a while into the cab. I fixed that, but I did not like how the tube had to feed into the cab. For a non race application, it is so much simpler to run a quality aftermarket electric gauge. Modern electric sender are so much better than they were 30 or 40 years ago. If you break a mechanical oil pressure line or the gauge fails, you have a major oil leak in the cab. I really like my new Autometer gauges and they are not that expensive.
12-12-2019 12:09 PM
John Strenk
Quote:
Originally Posted by TerryHowe View Post
I don't, but a lot of mechanical temperature sensors I've seen are just running a solid piece of copper wire into the cab to conduct the temperature, so I wouldn't expect more accurate results if that is the intention. You are essentially moving the sending unit into the cab.
I think that copper wire is actually a copper tube that contains a fluid that pushed the meter movement as it expands.
That is why the sensor end has to be so big and have a big fitting to hold it in place.
12-12-2019 11:52 AM
TerryHowe
Quote:
Originally Posted by steve801 View Post
Does anyone have a resource for a mechanical water temp sending unit / gauge that would fit this small thread port?
I don't, but a lot of mechanical temperature sensors I've seen are just running a solid piece of copper wire into the cab to conduct the temperature, so I wouldn't expect more accurate results if that is the intention. You are essentially moving the sending unit into the cab.
12-12-2019 11:47 AM
John Strenk
Quote:
Originally Posted by steve801 View Post
John, I assume the "4.0" you mention is another engine???
I live secluded in my own 258 straight six world...is there a specific year/model vehicle to ask for when I go to the auto parts store?
Thanks
The 4.0 was the replacement for the 258 4.2
A lot of the parts that fit a 258 can fit a 4.0 I think it started around 1987 to 2006..

Here is the 4.0 thermostat housing. This one is for a 97-06 Jeep Wrangler.



https://www.quadratec.com/products/51209_1008.htm

As you can see, it has a port just perfect for the temperature sensor and it bolts right onto a 258 block.
12-12-2019 08:26 AM
steve801 John, I assume the "4.0" you mention is another engine???
I live secluded in my own 258 straight six world...is there a specific year/model vehicle to ask for when I go to the auto parts store?
Thanks
12-12-2019 08:23 AM
steve801 i did think of adapting it into that same port but was hoping for something out there that was more of a direct fit...thanks for your input!
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