Water Temperature Icon

[bwatson0330]

Hello,

My water temperature ICON on the instrument panel lights up after driving about 15 miles. The temperature guage seems to be working fine. The needle is in the cold position when I first start the car and then moves up to the middle range. This just started happening a couple of days ago. Does anyone have any ideas? 1993 LS400

Thanks.

[landar]

I will take a stab at this. Perhaps there is a sensor on the coolant reservoir that is either faulty

or your coolant reservoir really is low. The sensor is trying to warn you that the coolant is low before

the car actually overheats. That may be why the temp gauge reads normally. It isnt low enough to cause

a real problem just yet.

Really quite elementary, my dear Watson.....(sorry, couldnt resist) :whistles:

[bwatson0330]

I will take a stab at this. Perhaps there is a sensor on the coolant reservoir that is either faulty

or your coolant reservoir really is low. The sensor is trying to warn you that the coolant is low before

the car actually overheats. That may be why the temp gauge reads normally. It isnt low enough to cause

a real problem just yet.

Really quite elementary, my dear Watson.....(sorry, couldnt resist):whistles:

Thanks Landar,

That was the first thing I checked. I noticed the collant reservoir was a little low so I filled it to the proper level. I also half way pulled of the cover to the left of the fill cap (must be the sensor) and it was all "gooey". Probably shouldn't have touched it at all. Even after filling, it still comes on. I did notice a small "dent" in the top of the reservoir cap. It may even have a small hole in it. Not sure nothing seems to be venting out of it.

Thanks for your response.

[landar]

It sounds like you are on the right track and that it is a misbehaving sensor or connector.

Electrically, I am not sure how the sensor works but it is probably rather simple. Perhaps grounding

a wire will fool the computer into thinking the fill level is fine. But then again, maybe it is looking for

+12 volts. In either case, that of course is not a long term solution, only verification.

I would be searching for a new sensor or cleaning the one you have. Pull out the entire reservoir

system and give it a good cleaning. If it is really messed up you might even check with a local

junk yard for an entire reservoir system in better shape.