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Temp Gauge question

K

ktwalker01

NAXJA Forum User
Location
Jackson, WY
I searched around a bit for what the temp gauge should be reading but I'm not to sure on my 99 4.0 ax15 4x4 if this is a normal range for the temp. Anyways on the 97+ style cluster my temp reads steady at the line just below 210, I dont know if that represents 190 ish I have no idea. I recently replaced the radiator and tstat for a 195*, but somewhat of a cheap one.

Let me know if that is a normal reading or if it should really be sitting steady on 210*

I live in Miami Florida btw.
 
200-210 F is where most 4.0 engines run. There is a bit of variation between engines.

And there can also be a bit of "inaccuracy" between the sending unit and the gauge.

If you REALLY want to know, get a hold of an infrared point and shoot thermometer and point it directly at the thermostat housing.

But yours sounds fine................
 
yeah I have one of those i never trust it though, my gas mialage has gone down a bit thats why i ask.. then again with 198,000 miles you never know lol
 
Hmmmm....

Cheap thermostats and reman water pumps usually end up costing you a replacement engine. Not such a bargain after all.

Stant SuperStat Premium 195 degree.

Engine should run at 200-210 range, depending on other factors of individual vehicles.
 
It's a superstant not premium i think it was like 7$, I spray painted a spot on the thermostat housing flat black (a shiny semi reflective surface doesnt work well for those infrared guns) and i read a steady 190-205 mostly floated around 195 after about 12 minutes and a quick zip around the block w/o the ac.

But the interior gauge still read far below the 210 mark. Call me anal but i'm wondering if I should just replace this 12 year old temp sensor?.. Or aint broke dont fix it lol... thats a tough one for me to live by
 
Well, the CTS in the thermostat housing feeds data to the PCM, and the PCM sends the signal to the temperature gauge in the IP.

You can pull the CTS and clean any scale off of it and reinstall it--that may change its readings. If you replace it I recommend the dealer. There have been reports of a number of 97+ aftermarket CTS that are "out of spec" when tested.
 
Thanks, I'm gonna go on a 600 mile road trip this weekend and if the mpg is far below 23 like I normally get on the highway Ill break out the multi meter and go to town on the sensors. I feel like im driving a ticking bomb because nearly all the sensors are stock (198,000), I keep a spare cps with me always though.

The only reason I asked this was because the gauge used to always camp out at 210 and recently its been lower and my in town mileage has gone from 19 to 15..
 
When you say it's FAR below 210, how far do you mean?

What is the temp at the 1/4 mark position? Being metric, my temp guage is 40 at the low mark, 100 at the top and 125 at the high mark. Not linear, so I was guessing about 75-80 deg. C at the 1/4 spot = 165-175 F?

After changing my thermostat last month (I was going over 100, up to about 110 - 115 for a few days) it now runs cooler, about halfway between 1/4 and 100 C.

I am just wondering if it is running overly cool or if this sounds like the right spot on the guage. I seem to remember it being a hair under 12 o'clock on the dial in the past.

I have not done a point and shoot measurement, need to borrow a thermometer for that. I'm just wondering if I am misremembering where the needle used to sit.
 
While we're on the topic of temp gauges...what's the # of the line between 100 and 210? I've got a 93 and my temp likes to sit at that line =/
 
Bdiddy11 said:
While we're on the topic of temp gauges...what's the # of the line between 100 and 210? I've got a 93 and my temp likes to sit at that line =/
Click to expand...

TEMPERATURE GAUGE RESISTANCE TABLE

Application & Test Temperature Ohms

100 F (38 C) ................... 1365.0 ohms
220 F (104 C) ......................93.5 ohms
260 F (127 C) ......................55.1 ohms

Buy yourself an assortment of resistors from RS, remove the wire from the sender in the back of the head, then start adding resistors until you get the indication on the gauge in question. That will give you an approximate idea.
 
ktwalker01 said:
Thanks, I'm gonna go on a 600 mile road trip this weekend and if the mpg is far below 23 like I normally get on the highway Ill break out the multi meter and go to town on the sensors. I feel like im driving a ticking bomb because nearly all the sensors are stock (198,000), I keep a spare cps with me always though.

The only reason I asked this was because the gauge used to always camp out at 210 and recently its been lower and my in town mileage has gone from 19 to 15..
Click to expand...
Make sure you're carrying a couple feet of extensions, a ratchet, a wobble joint, and an 11mm socket as well :thumbup:

I'd have to bet maybe your upstream O2 sensor is getting a little sluggish, or maybe winter gas has you down. When was the last time you replaced the upstream O2? If the answer is more than 100k miles ago, or never, toss a new one in it and see if it helps. The downstream I wouldn't bother changing, it is only there to tell if the cat works or not, as long as it isn't tripping a CEL (either one relating to the sensor, or one relating to the cat) you are good to go.
 
What is RS?

Curious because if i've been driving around a lot, and sitting at idle, the temp finally goes up to 200-210 but once I get going again and the air starts circulating again it goes down.
 
Radio Shack.

Sounds like your thermostat may be stuck open. Your gas mileage is probably pretty low like that, I was getting 9-11mpg with my MJ till I replaced the thermostat, which fixed my heat and improved my gas mileage (16-17mpg on summer gas driving it like I stole it.) It paid for itself after a couple days of commuting.
 
Someone said Radio Shack? (see screen name)

My mileage is down as well. Im getting 13mpg on average so far, winter gas and extended warm up times really kill the mileage. I average around 17 in the summer months. This is in my '96 with the 4.0 and Aw4 on 31" GY MTR tires. I only do city driving which does not help either.

Gave it a full tune up, new fluids, and new o2's before winter, guess my heep likes to keep the oil companies nice profitable.
 
So I averaged about 19 so I guess I was freaking out about the gauge looking funny. The o2 sesors age is unkown i got the rig in 2008 with 140k on her and now im closing in on 200.
 
Probably time to splurge on a new upstream o2 sensor.

Bosch.
 
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