mt_goat

Has anyone figured out what temp the factory temp gauge starts to show an overheated condition? I've had my coolant up to as high as 225 deg F (monitored by an Isspro temp gauge as well as OBDII) and the factory gauge stayed pegged in the middle without even a hint of overheating.

I'm wondering if I may have been running hot for many years and not even known it until I installed an aftermarket temp gauge. My factory gauge has never shown anything above the middle in 14 years.

That factory temp gauge seems to be only slightly better than an idiot light.

Joe's Toy

Sorry I don't have an answer for you but I've been wondering the same thing... And I totally agree with you on the idiot light thing.

curtiswyant

As long as it's not boiling over, I wouldn't worry about it. You'd be surprised how much heat your system can take

mt_goat

That's comforting. I wonder how much it effects the head gasket though, and how many people out there blew a HG because they were running hot and didn't even know it. The more it heats up the more thermal expansion there is and the more stress the HG has.

Yeah I agree, boiling coolant would be like a melt down and the worse case condition, but it would be nice to have a little warning that it is about to happen in advance of the cloud of steam from under the hood.

Robrt32

Mine stays just under half way.. The only time it tried to run hot on me it did get over half way just a little and i shut her down.. Put a thermostat in and haven't had another issue yet.. thats a couple years ago

95RunnerSR5

i'm using a sunpro mechanical gauge. All i had to do was buy the right brass fitting from lowes and drill the inside of it out a little..

AH64ID

Pretty sure I did... When flushing my engine it got 2/3 of the way to red, from the normal 1/2 way spot, not sure why as it was just at idle... Anyhow 1K later the HG blew... thats my best guess..

With OBDII I have seen as high as 202 on my 07, and the needle is in the same spot from 165-202.....

Yeah, really a fancy idiot light....

Now it would be tricky, but you could pull the temp sensor out, put it in a can of your waterless coolant, and put it on the bbq(since its easiest to get close to your truck)... see where the coolant needle moves... you will probably need a candy thermometer to see where its at. Thou the OBDII could tell you too..

neoworm0

I think a better gauge would just make me panic all the time. Everytime it moved I would think I was going to blow a stupid HG. Ignorance is bliss. I've pretty much just trained myself to constantly monitor the stock gauge. If it ever goes over where it normally sits, which it never seems to do, I'll shut her down. Probably not the best strategy but with the mileage I'm at It'll just be an excuse for a 3.4.

Sorry not much help I guess.

Kaydon

I'm pretty sure that's why the gasket in my yota blew.

notanymore

i found out that my temp gauge was messed around the same time i installed my aftermarket gauge. with the tempature sender unplugged my gauge still "moves like one might expect" but its unplugged so it kinda made me wonder how long it was like that. but the aftermarket gauge was one of the better mods iv done. but that is one thing i have wondered, just how hot overheating really is.

mt_goat

I think I found an answer from Marge:
https://www.yotatech.com/forums/show...9&postcount=52

AH64ID

Thats warm.....

Ksane

This drove me nuts when I 1st installed my AutoMeter temp gauge. There's 2 water temp sensors. The gauge in your instrument cluster reads from the sensor in your intake manifold (it reads the water temp in the engine). I hooked my aftermarket gauge up to the sensor that's on *top of the engine. That's where the water is the very hottest right before it goes into the radiator to get cooled off.
I read a post on here somewhere where a guy checked the water temp in both those places. The engine temp was nice and cool (170 or so) yet the water temp at the *top sensor (where your aftermarket gauge installs) was 220 or so. My aftermarket gauge will read up to 220 if my AC is on and I'm in slow traffic. Yet my cluster gauge (engine temp) reads right in the middle.
So I'd say the gauge on your instrument cluster is correct-it's reading the actual engine operating temp. The aftermarket gauge is reading the temp at the hottest place after it's already left the engine.
Sorry if I didn't explain it very well. It's clear in my mind but sometimes the words don't come out right.
Someone correct me if I'm wrong.
Mitzi

Ksane

I read this after I'd just posted, but it's because your temp gauge on your dash is hooked to the sensor in the manifold, not the temp sensor at the top of your engine. So it *is still working. I questioned a bunch of people about this and the only person I found who knew was 4Crawler on this forum. So oddly enough, most people don't realize it.
Mitzi

dcg9381

This may help.. This is for the ECU sensor, but you can pull the plug, put an ohm meter on it and approximate your tempature in degrees.
I use the stock ECU sender for data on megasquirt. Engine seems to run 190-204 degrees, +/- 5 degees accuracy, I'd guess.

ewong

Tech info..

The 22RTE (turbo) engine had a temp sensor on the outlet neck.
Its a good part to get to measure the temp of the coolant AFTER It leaves the intake manifold - aka abut as hot as its going to get.

I used to run an autometer "low temp" guage in there (they kept frying sensors). It was kind of fun to watch the thermostadt "pump" for the first 20+min of driving (yes - it opens and closes)

Standard driving has the temp at 200deg. Its a stock 180 thermo

HD driving (climbing, AC, summer etc) has temps in the 220 range.