98 LS400 overheating/malfunctioning temp gauge?
#17
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#18
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So I drove my LS for the first time in weeks the other day.
Temp gauge is still two bars higher than it should be. Oddly the auxiliary electric engine compartment fan is running all the time now. It's running at like 100% speed, and is really loud. I thought it was only supposed to run if you're pushing the car/driving in a really hot climate?
It's only about 90F here (32C). Is this fan driven by the temp gauge? Or is my temp gauge issue just a symptom of something else?
Thanks.
Temp gauge is still two bars higher than it should be. Oddly the auxiliary electric engine compartment fan is running all the time now. It's running at like 100% speed, and is really loud. I thought it was only supposed to run if you're pushing the car/driving in a really hot climate?
It's only about 90F here (32C). Is this fan driven by the temp gauge? Or is my temp gauge issue just a symptom of something else?
Thanks.
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So I drove my LS for the first time in weeks the other day.
Temp gauge is still two bars higher than it should be. Oddly the auxiliary electric engine compartment fan is running all the time now. It's running at like 100% speed, and is really loud. I thought it was only supposed to run if you're pushing the car/driving in a really hot climate?
It's only about 90F here (32C). Is this fan driven by the temp gauge? Or is my temp gauge issue just a symptom of something else?
Thanks.
Temp gauge is still two bars higher than it should be. Oddly the auxiliary electric engine compartment fan is running all the time now. It's running at like 100% speed, and is really loud. I thought it was only supposed to run if you're pushing the car/driving in a really hot climate?
It's only about 90F here (32C). Is this fan driven by the temp gauge? Or is my temp gauge issue just a symptom of something else?
Thanks.
![](https://cimg0.ibsrv.net/gimg/www.clublexus.com-vbulletin/440x294/radiator_temp_sensor_019f1b618643d60cccab9926a582e4eac787edd2.png)
#20
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my a/c fan on my 98 LS runs 100% of the time as well. I ordered the ECT switch connector that is shown in the pic a few weeks ago. Have not put it on yet. Anyone have any thoughts on the best way to replace this. I assume coolant will be lost if the old one is removed and replaced ? Do i open the petcock and let the coolant drain out and then replace it ? hopefully that will resolve my a/c fan running all the time. thanks
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BNastee (03-23-22)
#22
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I had the same problem with my 1990 LS400 with 280K miles.
Temperature gauge showed above Cold line in the morning before even car was started. After running the car for a bit the gauge would rise between half and full line.
Following checks were done: Coolant level normal with no leakage, Fan clutch working properly, Replaced the Temperature Sendor Gauge (83420-16020), Coolant was flushed 20K miles ago, Thermostat fairly new.
Unfortunatly nothing worked and I was going to look at the Temperature Receiver part in the cluster until I decieded to gently tap the cluster which fixed it. I am ecstatic.
If your temperature gauge is starting above cold even thouigh the car is been sitting over night. Turn the ignition on and gently tap the cluster above the left/driver side of the dash.
Thanks.
Temperature gauge showed above Cold line in the morning before even car was started. After running the car for a bit the gauge would rise between half and full line.
Following checks were done: Coolant level normal with no leakage, Fan clutch working properly, Replaced the Temperature Sendor Gauge (83420-16020), Coolant was flushed 20K miles ago, Thermostat fairly new.
Unfortunatly nothing worked and I was going to look at the Temperature Receiver part in the cluster until I decieded to gently tap the cluster which fixed it. I am ecstatic.
If your temperature gauge is starting above cold even thouigh the car is been sitting over night. Turn the ignition on and gently tap the cluster above the left/driver side of the dash.
Thanks.
Last edited by khebre; 06-06-20 at 08:25 PM.
#24
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my a/c fan on my 98 LS runs 100% of the time as well. I ordered the ECT switch connector that is shown in the pic a few weeks ago. Have not put it on yet. Anyone have any thoughts on the best way to replace this. I assume coolant will be lost if the old one is removed and replaced ? Do i open the petcock and let the coolant drain out and then replace it ? hopefully that will resolve my a/c fan running all the time. thanks
If original wiring and contacts intact, then simply replace the shell.
However, you will need to make room to access the wiring...
Connector shell replacement how-to example:
https://www.clublexus.com/forums/ls-...-housings.html
#25
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Currently have the same issue with my 2000 LS400
Temp gauge stays at 3/4 like op picture of the temp gauge.
I’ve done the following:
STILL THE SAME PROBLEM.
now debating on if i have a faulty temperature sensor? or on the post was mentioned a faulty cluster but no real solution.
instread of playing the guessing game and just keep changing out parts. has anyone come up with a solution for this problem?
also is it okay to keep driving the car with this problem? It’s because it is my daily
Temp gauge stays at 3/4 like op picture of the temp gauge.
I’ve done the following:
- flushed coolant from 3 drain plugs
(radiator, left side of engine, and right side of engine)
2. replaced thermostat with a OEM one making sure the hole is at the 12 o’clock position.filled with toyota red coolant from filler neck (on throttle body) topped the coolant reservoir to max line.
3. Burped the cooling system with the heater on blast and car at an incline in an attempt to get all the air out. STILL THE SAME PROBLEM.
now debating on if i have a faulty temperature sensor? or on the post was mentioned a faulty cluster but no real solution.
- NOTE: i did unplug the temperature sensor and plug it back in it DOES seem to be working but still the same issue the temperature gauge sits at 3/4 with no signs of struggle or hesitation.
- NOTES: same issue no check engine light and measured temperature with a gun it stayed between 185-195F and never exceeded 200F from normal driving.
instread of playing the guessing game and just keep changing out parts. has anyone come up with a solution for this problem?
also is it okay to keep driving the car with this problem? It’s because it is my daily
#26
Lexus Fanatic
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Hook up a scan tool and read the true temperature the sending unit is piping into the ECU. The gauge reading is interpreted through software.
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BNastee (03-23-22)
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