Coolant Temp Gauge
#1
Coolant Temp Gauge
Quick question for the gurus. I have an '88 Xtracab with a '94 22re swapped in. The coolant temperature gauge works, but it will only ever climb to maybe an 1/8" above the bottom mark. That is even when crawling around on trails really slow when it should be getting hot. It does move, just hardly at all. Did the sender change somehow between these years that my reading seems to be so low?
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#6
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When you do get the thermostat make sure it for the right temperature. I believe OEM is 195 degrees. If you get one that is colder you will be running rich condition and your gauge will never rise very much. Also check your fan clutch, it may be bad keeping your engine too cold.
#7
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When you do get the thermostat make sure it for the right temperature. I believe OEM is 195 degrees. If you get one that is colder you will be running rich condition and your gauge will never rise very much. Also check your fan clutch, it may be bad keeping your engine too cold.
From the 93 Truck FSM ( http://personal.utulsa.edu/~nathan-b...51thermost.pdf ) the 22re engine t-stat is:
86–90*C (187–184*F)
Last edited by mt_goat; 04-15-2010 at 01:28 PM.
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#9
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#10
When you do get the thermostat make sure it for the right temperature. I believe OEM is 195 degrees. If you get one that is colder you will be running rich condition and your gauge will never rise very much. Also check your fan clutch, it may be bad keeping your engine too cold.
From the 93 Truck FSM ( http://personal.utulsa.edu/~nathan-b...51thermost.pdf ) the 22re engine t-stat is:
I run with a wide band air/fuel ratio gauge and a 20* cooler t-stat and can say running a cooler t-stat doesn't make you run rich.
I run with a wide band air/fuel ratio gauge and a 20* cooler t-stat and can say running a cooler t-stat doesn't make you run rich.
#11
When you do get the thermostat make sure it for the right temperature. I believe OEM is 195 degrees. If you get one that is colder you will be running rich condition and your gauge will never rise very much. Also check your fan clutch, it may be bad keeping your engine too cold.
#12
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Sounds like a case of not broken, doesn't need fixing. I would say that is the normal position for your gauge, with the setup that you have.
If you really wanted to check everything out, you could check the temp. sensor's resistance at various temps, from cold to normal operating temp. If you want to make sure the gauge will tell you that you're overheating before problems would occur, you could remove your sensor, but leave it hooked up. Run longer wires if you have to. Then, place the sensor in a container of really hot water, maybe close to boiling. Turn your key on, and see what the gauge does. If it doesn't read any higher than normal, you have reason to fret. If it does read higher than normal, you know that you don't want to see it there, but everything is working ok.
If you really wanted to check everything out, you could check the temp. sensor's resistance at various temps, from cold to normal operating temp. If you want to make sure the gauge will tell you that you're overheating before problems would occur, you could remove your sensor, but leave it hooked up. Run longer wires if you have to. Then, place the sensor in a container of really hot water, maybe close to boiling. Turn your key on, and see what the gauge does. If it doesn't read any higher than normal, you have reason to fret. If it does read higher than normal, you know that you don't want to see it there, but everything is working ok.
#13
Sounds like a case of not broken, doesn't need fixing. I would say that is the normal position for your gauge, with the setup that you have.
If you really wanted to check everything out, you could check the temp. sensor's resistance at various temps, from cold to normal operating temp. If you want to make sure the gauge will tell you that you're overheating before problems would occur, you could remove your sensor, but leave it hooked up. Run longer wires if you have to. Then, place the sensor in a container of really hot water, maybe close to boiling. Turn your key on, and see what the gauge does. If it doesn't read any higher than normal, you have reason to fret. If it does read higher than normal, you know that you don't want to see it there, but everything is working ok.
If you really wanted to check everything out, you could check the temp. sensor's resistance at various temps, from cold to normal operating temp. If you want to make sure the gauge will tell you that you're overheating before problems would occur, you could remove your sensor, but leave it hooked up. Run longer wires if you have to. Then, place the sensor in a container of really hot water, maybe close to boiling. Turn your key on, and see what the gauge does. If it doesn't read any higher than normal, you have reason to fret. If it does read higher than normal, you know that you don't want to see it there, but everything is working ok.
#14
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You're using a crappy factory analog gauge that is notorious for failing. You want to to know the accurate temp of your motor you need to run an aftermarket temp gauge with a number readout.
The guages in my SR5 cluster, my brothers and ive even had a standard cluster gauge fail. It's common.
a 180F T-stat is to low. In my own experience with T-stat experimenting, once to much fluid begins circulating in the block the motor never heats up to operating temp. This is caused by 3 reasons, first one is obvious, no t-stat, second one is a t-stat thats rated to cool (180F) ...
btw the FSM says the T-stat should open between 187 and 194F,
http://personal.utulsa.edu/~nathan-b...51thermost.pdf
This page in the 93 FSM is a mistype, "187-184" ... 86C-90C is 187F to 194F. This is the range at which time the valve begins to open, it should be completely open by reaching 100C (212F)
The third reason a motor won't run up to operating temperature is an oversized gas release nipple (or hole). Any hole larger than 1/16" is gonna be to large on a 22r. This is a hole that is drilled through the T-stat flange to allow gas (air) to move through the stat and still restrict fluid movement. To big of a passage and to much fluid moves through the t-stat which makes the motor take longer to heat up or it never will (depending on how large you've drilled your hole) .. I've never seen a t-stat that came with this nipple cause this, only seen this by drilling a hole to large into a t-stat that doesnt have this factory hole.
The hole is critical as well. Without the hole air gets trapped below the -stat as the motor cools and the t-stat closes. When the motor begins heating up, the t-stat doesnt reach it's opening temperature so it doesnt open, which causes the motor to overheat.
The usual sympton of this is seeing the needle rise at a normal rate, but never level off at in the "middle" It'll continue rising then suddenly drop down rapidly (as the t-stat finally opens as the wax melts) or in my own experiences, may not drop at all, but a good rev of the motor creates more pressure in the cooling system and allows coolant to finally reach the t-stat so it opens.
This is extremely bad for the motor, you're asking for a headgasket failure or the head to crack. (I've had both happen as a result from overheating)
I have a aftermarket temp gauge obviously and I run at 195-198F all day long, the E-fan I run is set to about 208F and does an excellent job of not allowing the motor to run over 210F .. I also sport a 3-row Radiator.
Goodluck mate! cheers
The guages in my SR5 cluster, my brothers and ive even had a standard cluster gauge fail. It's common.
a 180F T-stat is to low. In my own experience with T-stat experimenting, once to much fluid begins circulating in the block the motor never heats up to operating temp. This is caused by 3 reasons, first one is obvious, no t-stat, second one is a t-stat thats rated to cool (180F) ...
btw the FSM says the T-stat should open between 187 and 194F,
http://personal.utulsa.edu/~nathan-b...51thermost.pdf
This page in the 93 FSM is a mistype, "187-184" ... 86C-90C is 187F to 194F. This is the range at which time the valve begins to open, it should be completely open by reaching 100C (212F)
The third reason a motor won't run up to operating temperature is an oversized gas release nipple (or hole). Any hole larger than 1/16" is gonna be to large on a 22r. This is a hole that is drilled through the T-stat flange to allow gas (air) to move through the stat and still restrict fluid movement. To big of a passage and to much fluid moves through the t-stat which makes the motor take longer to heat up or it never will (depending on how large you've drilled your hole) .. I've never seen a t-stat that came with this nipple cause this, only seen this by drilling a hole to large into a t-stat that doesnt have this factory hole.
The hole is critical as well. Without the hole air gets trapped below the -stat as the motor cools and the t-stat closes. When the motor begins heating up, the t-stat doesnt reach it's opening temperature so it doesnt open, which causes the motor to overheat.
The usual sympton of this is seeing the needle rise at a normal rate, but never level off at in the "middle" It'll continue rising then suddenly drop down rapidly (as the t-stat finally opens as the wax melts) or in my own experiences, may not drop at all, but a good rev of the motor creates more pressure in the cooling system and allows coolant to finally reach the t-stat so it opens.
This is extremely bad for the motor, you're asking for a headgasket failure or the head to crack. (I've had both happen as a result from overheating)
I have a aftermarket temp gauge obviously and I run at 195-198F all day long, the E-fan I run is set to about 208F and does an excellent job of not allowing the motor to run over 210F .. I also sport a 3-row Radiator.
Goodluck mate! cheers
Last edited by drew303; 05-04-2010 at 07:37 PM.
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My money is on either the sensor reads at a different resistance than the earlier sensor or the gauge is failing....with the likely culprit being more towards the gauge failing. I have the SR5 cluster in my 95 truck and my voltmeter is pegged at 18 volts. I thought my new alternator was failing so I took it in for warranty work only to find out it tested fine but that the gauge is bad.
I'll eventually put an aftermarket gauge in but after i get bigger tires and some new paint!
I'll eventually put an aftermarket gauge in but after i get bigger tires and some new paint!
#17
Contributing Member
btw the FSM says the T-stat should open between 187 and 194F,
http://personal.utulsa.edu/~nathan-b...51thermost.pdf
This page in the 93 FSM is a mistype, "187-184" ... 86C-90C is 187F to 194F.
#18
Contributing Member
You have it backwards, closed loop is where the ECU is using all the sensors for A/F ratio feedback and adjustment. Open loop is where it runs rich (like at startup or wide open throttle). BTW I'm usually out of open loop before I can get out of the driveway, way before the t-stat opens or before it gets close to OP temps. Running a cooler t-stat will not in my experience cause you to run rich and I monitor my A/F ratio constantly.
Last edited by mt_goat; 05-05-2010 at 06:05 AM.
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