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Discussion Starter #1
Hi Folks,

I'm still relatively new to Broncos and have a question regarding normal operating temp. Out of the 2 Broncos I own, only the 93 runs. So I can't use the other one to compare the temp gauge needle among the two.

When I first got the 93 a few months ago, I noticed that the temp gauge needle rarely ever reached the letter "n" in the word "normal" on the face of the temp gauge unless I had driven it for more than an hour. The thermostat was recently replaced with a new, OEM one from the dealer. I noticed that the old thermostat was stuck open, which explains why it took so long to reach normal operating temp. It now reaches normal operating temp fairly quickly, within 10 minutes.

But where is the temp needle gauge supposed to be for it to be normal? In between the letters "o" and "r", or right in the middle of the gauge face, right on the letter "m"? With the old, stuck thermostat, the temp gauge needle would usually get up to the letter "r" after driving it for 2 hours. Sometimes it would sit right in the middle, on the letter "m" if I pushed it up a hill. With the new thermostat the needle is on the letter "r", and sometimes on the letter "m" if I push it. Is that normal, or is it running a tiny bit too hot?

FWIW, the temp needle on the other cars in my family (Toyota and Chevy van), all stay a bit under the half-way mark, no matter how hard I drive it, not right in the middle of the halfway mark like it does on my 93 when I push it.

The 93 has a 302, E4OD combo. I also drained the old coolant and had it flushed.

Thanks for any extra info.
 

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The temp gauges isn't completely an idiot light, it just doesn't have the temp scale on it. The oil pressure gauge on 87s and up is an idiot gauge and only registers Normal of ~6psi.

To answer your question, Normal could be anywher from `180 to~ 215 F. There are two sending units on my 90 EFI, one for the shit gauge and one for the computer.
 

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The Anti Yam!
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BlueBronco said:
The temp gauges isn't completely an idiot light, it just doesn't have the temp scale on it. The oil pressure gauge on 87s and up is an idiot gauge and only registers Normal of ~6psi..
My books say 8psi

It may not completly be an idiot light, but they are verry inakurate. My budies temp gage in his 93 Mustang GT would go up a notch every time you turned on or used something electrical :shrug

The Factory gage in my 86 would act completly eratic, absolutly no rhym or reson to it. Swtched to mechanical gages and every thing read normal and verry stable.
 

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Discussion Starter #5
Thanks for the replies, fellas. I hadn't thought of installing a mechanical temp gauge. That sounds like a good idea. My temp gauge seems to be working with some form of accuracy, but unfortunately it doesn't provide an accurate temp reading in Fahrenheit. It read a cool reading when it had the old thermostat that was stuck open, and slowly moved to a warmer reading as it warmed up.
 

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I don't think they are too unreliable. That is, I know the oil gauge works enough to let you know when there is no oil in there. One time when I was working away from home for a construction company...they didn't tighten the drain-plug and the oil drained out resulting in irradic gauge reading(s).

But in the long run, I would like to put an completely different set/type of gauges.

:beer
Bill
 

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The guages work. They may not be insanely accurate to the degree, and they do all sort of have their own charcter. Mine runs just below the "N" on cold days, and around the "O" on warm ones. you can see it heat up, and cool down when the thermostat opens. If it starts rising to the "MA", I know it's time to crank the heat and start thinking about pulling over.

brad
 

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Screw the Jeep Thing
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As long as the factory guages read in the normal range thats all that matters. If it get outside of that range thats when you start to worry.

Since we're throwing out examples here. my '93 Bronco's Temp guages on days when it's below 10 degrees will stay below Normal for 10-15 mins. Then shoot up to amost out of the Normal range to Hot. IT will over there till the next time I mash the gas, then it will go back ot it's normal position right about the O.
 

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Discussion Starter #9
Thanks for the replies, Brad and Bronco85. If my temp gauge is "accurate", then mine may be running a bit warmer than Brad's. After it heats up, mine goes past the "n" and hovers around the "r". If I mash on the gas, it'll get up to the "m" and stay there. I've never seen it go past the "m", though. If I let off the gas, it'll drop back down to the "r". I'm wondering if the reason the old thermostat was stuck open is because the previous owner made it that way?
 

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Mine is around the O or R as well...sorry I didn't put this in my first post, I meant to.

Anyway, just bear in mind that all engines are different and it could very well be higher or lower than that. You'll know soon enough after keeping an eye on it what normal for your Bronco is.

:beer
Bill
 

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Discussion Starter #12
Sounds like most have it around the "O", and sometimes "R" if it gets warmer. Yep, real technical - hehe. Mine's seems to be a tad bit warmer than y'all's, but Bill brings up a good point. Thanks for the info, fellas.
 

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Yep different trucks will read different.

You had 3 engine choices: 300, 302, 351
bunch of Thermo choices: 170, 175, 180, 185, 190, 195(These are the ones I've been offered at parts stores)
Tranny sizes: This does affect engine temp alittle when the tranny gets hot.
Then of course you have driving style.

I once heard that the letters on the guage represent what thermost you have in the truck N being the 170 and L being the 195. I don't know if this is true or not though, I've never tested it. I run a 180 Thermostat in my '93 Bronco and normal driving and idle it runs between the "O" & "N" so it kinda makes sense that way.
 

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i'd be cautious about buying an aftermarket mechanical gauge. i have tranny temp, coolant temp, and oil pressure. probably the three most stressfull and i have them all in my eyesite every minute i drive this thing on the highway. you won't be able to take your eye off the gauge... you get nervous if it ever goes 1 degree over the 195 degrees or whatever. it doesn't matter as long as it stays within a range, but a range in the "middle." of course, just my opinion. and if you just have to get a mechanical, i've had many different brands. it really doesn't matter. if you can though, stay away from wal-mart.
 

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I don't think they are too unreliable. That is, I know the oil gauge works enough to let you know when there is no oil in there. One time when I was working away from home for a construction company...they didn't tighten the drain-plug and the oil drained out resulting in irradic gauge reading(s).
No oil pressure gauge is intended to monitor oil level. If anyone uses it as such you run a very real risk of shortening the life of your motor. The only thing that can monitor oil level is the dipstick.

The physical size and layout of the gauges changed between model years, so for one person with an '89 to say he's reading "R" while a guy with a '93 says the same thing is completely useless. Furthermore the accuracy of the gauges vary from truck to truck, even within the same model year. The best you can hope for is to say that your gauge is accurate *relative to itself.*
 

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TTBlows said:
Furthermore the accuracy of the gauges vary from truck to truck, even within the same model year.
Hell, and with the ages of the trucks we're talking about, it's not uncommon for the gauge to vary a little from day to day with humidity or ambient temperature.
 

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The Anti Yam!
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seboh said:
Hell, and with the ages of the trucks we're talking about, it's not uncommon for the gauge to vary a little from day to day with humidity or ambient temperature.
Exactly what I meant, unreliable.

Heck I've seen humidity mess with these things.

Mechanicals rule.
Very acurate.
tells you the actual temp/pressure with real numbers..
unaffected by temp electrical or humidity.

Cheap acurate insurance against engine damage.
 

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Yeah, but that doesn't mean much. One day, the needle is midway on "N", the next day it's between "O" and "R". When it swings way out to the right, the motor is still hot.

And an aftermarket electrical gauge will be as accurate as a mechanical. The mech. gauge might have faster response (depends on the brand and model), but not enough to matter with our motors. If you're going to buy mechanical, do it because you want full-sweep or something. But understand that a mechanical oil pressure or mechanical fuel pressure gauge can be dangerous if the line fails.
 

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seboh said:
Yeah, but that doesn't mean much. One day, the needle is midway on "N", the next day it's between "O" and "R". When it swings way out to the right, the motor is still hot.
Yep. You get to know real fast that when that needle swings past the "M" at a decent pace you probably need to pull over.

The gauges take a couple seconds to respond, but if you watch your gauge on a regular basis you get used to the behaviour of your truck. You'll be able to read that thing as well as any other gauge out there.

brad
 
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