Scan Gauge temp vs Toyota Gauge temp

JohnnyFish

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Coming across Arkansas yesterday, my new-to-me Scan Gauge 2 on my new-to-me truck showed a temperature spike from the normal 184-195 to 220, while the Toyota gauge didn't move. Did I have a steam pocket near the temperature sensor that feeds the ECU? Any idea what's going on here? Once the temperature spiked, it couldn't recover until I stopped for 20 minutes or so to let the truck cool.

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Irish Reiver

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I am assuming by Toyota guage you mean the guage in the bottom left of the display. You will notice that guage does not have any gradient marks or labels-same with the oil pressure guage. Bottom line is that the temp guage is more or less just for looks. The needle points to a meaningless point that is normally half way between C and H. There are electronics that keep it there even when your engine is cooking. If per chance it ever moves north of centre then chances are your cylinder head is cooking beyond well done.
On the positive side your choice of having a scan guage will give you an accurate measurement of what is really happening in your engine and quite possibly the opportunity to take evasive action if you see something untoward...unIike the Toyota guage.
 

StaticTorque

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I am assuming by Toyota guage you mean the guage in the bottom left of the display. You will notice that guage does not have any gradient marks or labels-same with the oil pressure guage. Bottom line is that the temp guage is more or less just for looks. The needle points to a meaningless point that is normally half way between C and H. There are electronics that keep it there even when your engine is cooking. If per chance it ever moves north of centre then chances are your cylinder head is cooking beyond well done.
On the positive side your choice of having a scan guage will give you an accurate measurement of what is really happening in your engine and quite possibly the opportunity to take evasive action if you see something untoward...unIike the Toyota guage.
This x2
If that needle ever gets up to the red, it’s already too late. Means basically nothing. I have an Ultra Guage and love it. This has recently happened to me sitting in traffic when it’s been 90+ degrees out.
Personally it keeps happening occasionally so I think I’m going to replace the fan clutch.
 

REKCUT

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Your factory dummy gauge settles in at the mid point once it reaches about 180 and doesn't move again until you go above 220. Thats why a scan gauge type reading or installing a digital one is very important. Many folks out there have no idea that their truck is struggling with cooling issues until its to late. Mine sits at 192 constantly and might go up to 196 if on a very long low rpm hill climb.

If you can see that your truck is getting into the 200 plus range and can work out the issues before you end up in the danger zone your so much better off. Usually its a van clutch issue but many other things may need serviced in the cooling world.

That factory "gauge" is really more of a "hey dummy, your truck is melting down" kind of message
 

Tedward

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The factory gauge can be modified.
Raven Tai temp gauge mod that got worked out a long time ago.
I did it and it and the needle does sweep more that before.
I've watched the factory gauge and the ultagauge. The factory gauge will move a bit as the temps go up/down as shown by the ultragauge.
I thought it was cool and did it. Just another cool idea from the minds of Mud.
 
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Of course it’s not the only vehicle where this is the case, but strange that they’d build such a fantastic machine like an 80 with a virtually useless stock gauge.
If Mr. T wasn't worried about it, maybe all this Mud OCD and talk of doom and HG popping if you occassionally spike up to 220 deg F is inflated? Otherwise why isn't the AC cutoff temp lower than 227 deg F? :hmm:
 
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True, but would be nice if it functioned more like the raventai mod, indicating temperature changes before it really starts to climb
Yeah I have the raventai mod, though sometimes I wish I didn't since I tend to worry when it goes into the red (even though it is only 217 deg F). :)
 

FMC80

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I noticed your oil pressure gauge is quite low compared to mine. Mine usually sits near the “H” but maybe that doesn’t mean anything like the temp gauge.
 

flintknapper

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Yep, the factory temp gauge is famous for it's 40° 'dead spot'.

Not sure the intent....unless it was to spare U.S. 'Soccer Moms' any concern with a constantly fluctuating temp gauge.

But it is....what it is.

It has sold a lot of ScanGauges...that's for sure.

ScanGauge temp.jpg
 

Heckraiser

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As stated above, the stock gauge is actually an idiot light in disguise. It will only warn you once you're already overheated. I've had my AC cut out a couple times before the gauge moved.
 

flintknapper

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As stated above, the stock gauge is actually an idiot light in disguise. It will only warn you once you're already overheated. I've had my AC cut out a couple times before the gauge moved.

Stock temp gauge has an approximately 40°F 'dead spot' where the gauge's needle will either not move, or not move enough to be readily noticed.
 

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