What color is your radiator fluid? (plus other topics) (2 Viewers)

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***UPDATE***

Got the LX back and guess what... the rear diff now locks! :cheers:
I drove the truck straight from the dealer to the park and tried out the lockers. I now hear a sound when I turn the locker switch to RR and the rear diff light stays solid, plus I can feel the resistance when turning. The dealer replaced the rear actuator plus a switch. I asked for the bad parts, but could only keep the switch because the actuator was covered under warranty, so it needs to be returned to Lexus.

Thanks for everyone's help!
 
Bill, good job. I see your gauge sensor curve does not flatten out as much as mine. As far as protocol, I slowly heated the sensor, and was constantly stirring the water bath to ensure the thermometer and sensor were the same temp. Other than that, there is not much else to do other than watch the resistence change as it gets hotter.

In case you continue to feel ambitious, the next step is to beg, borrow, or steal a decade resistence box and to observe what the dash gauge registers when you insert resistence varying from 50 - 10 ohms between ground and the engine coolant sensor connector. Then you will know what the gauge indicates for a temp range of 160 - 250 F.

Rich
 
Bill,

Just out of curiosity what was the age of the senders you tested. I was speaking with CDan about this last week. He had ordered another sender to put in inventory so he had one gauge sender and one ECU sender. He was offering to ship them to someone for testing. I think age might possibly explain some of the differences between your measurements and Rich's. I was thinking that we had to source a sender that had a little more resistance range at the higher temp. Cary's point about clipping a resistor got me thinking that as long as the gauge sender is up to spec we might be able to add a resister in parallel with the circuit to bias the gauge so that the reading is more reactive in the temps the engine normally near. It might mean the gauge would show normal temp as a 10 o'clock position versus the 9 it does now but an elevated temp say 215 would put it in the red zone (11) and 225 would be full scale. It’s just a matter of setting up a scale instead of "marks" that mean nothing.
 
Rich,

The way I did it was to put motor oil in a metal cup and heat it slowly with a large heat gun. The thing I was concerned with was the probe is about 5" long, so I was only able to put about 3" in the liquid. It was right against the sensor. Every 5 Ohms I would hit the trigger on the Raytek and take a temp reading. I never thought of it at the time, but I have some very accurate thermometers as I process my own photographic film. Of course I don't know if I could bring myself to stick one in a cup of oil. :eek:
I have about half the wiring out of the cruiser and no battery so I can't do any of the other tests.

ppc - They are the original sensors (1997). I was disappointed in that they were covered with red rust like stuff. I think part of it is from overheating and part from the fact that the motor has been drained for over a year and just sitting. I am going to do the headgasket before I put it on the road just in case.
Ya, Cdan is a little PO'd at me about the sensors he has. He called with an idea about them and I pointed out why I thought it would not work and ruined his day. ::) Hey, 99 brilliant ideas and one not so brilliant is a pretty good average, right? :D

Bill
 
Had a couple of hours to kill this morning so I read this thread. Reminded me of overheating issues I had last summer.

Here's what I learned about the temp guage (with an OBDII scanner hooked up while towing a boat. The 80's cooling system was f'd up at the time.

-The needle stayed in its normal, center position from 185 to 221 F.
-From 222 to 231F the needle moved above normal position.
-At 232F the needle just touched the red zone.

So according to Toyota, the coolant temp can be 230F and not be in the red zone. Scary.

Ed
 
Ed,

Did your AC cut out ?

Bill
 
Bill,

Yes, it cut out at 222F. I read in your posts that it's supposed to cut out at 226F, but mine had a 2% error.

Those 4 degrees would have made a big difference. It was about 115 degrees and we had to go slow enough to keep the temp at 221 to keep the AC on.

Ed
 

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