Temp gauge

[mtnrgr]

I had a similar experience on my old 94 3.0 5spd ranger. Heat worked, all was good, yet was reading low. I did alot to it to fix and I did.

This sensor only goes in so far before it stops. It does this due to how much it tightens into the intake manifold. I learned this the hard way years ago on my old 94 3.0 5spd ranger. I heard something while going a bit further to tighten, and i was refilling it started leaking. By doing that it cracked my lower intake manifold..I had to now replace that, I had a spare..what a job. Be careful to not over tighten.

The other thing is the how tight the connector is to it. Those circle connector on these sensors are not always secure and clean. Make sure its clean inside and make sure it fits on there snug.

After replacing the manifold, and putting a motorcraft thermostat and getting it up and running, the gage was still do the same thing..ugh ugh. I gave it a few days of good miles and still read low. I began checking into the gauge and cluster, swapped those out an no change. I checked that single wire connection ad it was loose. I cleaned and closed the whole to make it more secure when hooked up..that was the issue..all was working great for many years after. Check the connector.

Another thought is is there currently a aftermarket thermostat in this engine? I ask is, I now have a 97 3.0 5spd ranger. Let year I had some work done at my former mechanic shop, for the 2-3 months the temp gauge barely moved and other it would creep slowly. I checked the wiring and all is good. I found out that the shop had installed a aftermarket thermostat. Of cheap stuff these days, it was malfunctioning, I bought a motorcraft thermostat, installed and all has been good for 5 months now. After you install that new part, check the plug to see proper fitting. Put in some dielectric grease..that will also help. Drive it for a couple of days, its fixed great..if not I would look at the thermostat, and to make sure the cooling is bled properly.

 

[franklin2]

It only goes halfway because the threads are pipe threads or commonly known as NPT threads. They are tapered, they are smaller and then get larger diameter as you move up the sensor. All pipe threads are tapered, so they wedge themselves tight and give a watertight seal.

So be careful when tightening components with threads like this. The intake has plenty of meat around the hole, but I have ran across aluminum transfer cases with tapered pipe oil drain plugs, and someone has tightened them too tight and cracked the case of the transfer case causing a leak.

Your sensor for the gauge cannot trip the check engine light. There is a separate sensor for the computer, and that one can trip the light. More modern trucks have all this integrated together, but your older truck has it separate.

 

[Eddo Rogue]

There is a sensor and sender. I think the sender is what actually sends temp reading to dash gauge. I had to replace both, and burp the cooling system....a few times. I spliced a bleed valve fitting into one of the heater hoses to make burping it easier...otherwise parking on an incline radiator cap off worked fine.

 

[SenorNoob]

Your sensor for the gauge cannot trip the check engine light.

This.^ In 94 that has no connection to the PCM. That's partly what makes the 4.0 swap in earlier trucks so simple. None of the gauges connect to the PCM.

 

[1994xlt]

I had a similar experience on my old 94 3.0 5spd ranger. Heat worked, all was good, yet was reading low. I did alot to it to fix and I did.

This sensor only goes in so far before it stops. It does this due to how much it tightens into the intake manifold. I learned this the hard way years ago on my old 94 3.0 5spd ranger. I heard something while going a bit further to tighten, and i was refilling it started leaking. By doing that it cracked my lower intake manifold..I had to now replace that, I had a spare..what a job. Be careful to not over tighten.

The other thing is the how tight the connector is to it. Those circle connector on these sensors are not always secure and clean. Make sure its clean inside and make sure it fits on there snug.

After replacing the manifold, and putting a motorcraft thermostat and getting it up and running, the gage was still do the same thing..ugh ugh. I gave it a few days of good miles and still read low. I began checking into the gauge and cluster, swapped those out an no change. I checked that single wire connection ad it was loose. I cleaned and closed the whole to make it more secure when hooked up..that was the issue..all was working great for many years after. Check the connector.

Another thought is is there currently a aftermarket thermostat in this engine? I ask is, I now have a 97 3.0 5spd ranger. Let year I had some work done at my former mechanic shop, for the 2-3 months the temp gauge barely moved and other it would creep slowly. I checked the wiring and all is good. I found out that the shop had installed a aftermarket thermostat. Of cheap stuff these days, it was malfunctioning, I bought a motorcraft thermostat, installed and all has been good for 5 months now. After you install that new part, check the plug to see proper fitting. Put in some dielectric grease..that will also help. Drive it for a couple of days, its fixed great..if not I would look at the thermostat, and to make sure the cooling is bled properly.

I mean it is a cheap thermostats on the truck but the heat works well and gives no issues

 

[1994xlt]

It only goes halfway because the threads are pipe threads or commonly known as NPT threads. They are tapered, they are smaller and then get larger diameter as you move up the sensor. All pipe threads are tapered, so they wedge themselves tight and give a watertight seal.

So be careful when tightening components with threads like this. The intake has plenty of meat around the hole, but I have ran across aluminum transfer cases with tapered pipe oil drain plugs, and someone has tightened them too tight and cracked the case of the transfer case causing a leak.

Your sensor for the gauge cannot trip the check engine light. There is a separate sensor for the computer, and that one can trip the light. More modern trucks have all this integrated together, but your older truck has it separate.

Well shot that means my check engine light is somthing else…