Okay, I just replaced the radiator w/a rebuilt D-1 factory radiator, all new hoses, new LR fan clutch, (2) new sensors (one for the temp gauge & the other was for the electric fans (they both are in the thermostat housing)), a new LR 180 degree thermostat, and complete engine flush & brand new coolant. I am still having the same issues with the gage rising in town, and even more troubling, the gage jumps even higher when I use my left turn signal. Everything runs as normal on the highway & the left turn signal has no affect on the gauge at highway speeds (drove 25 miles at 70 with the left turn signal on. Should have seen the people staring ). They said there was no evidence of the heads leaking under pressure. The electric fans operate just fine too. What am I missing?? Is there a known short that would do this?

 

Do you have an OBD2 device that can give your actual temp?

 

My 97 has no sensors on the thermostat housing. The electric fans come on with AC, or under command of the ECU at other temps. The two sensors I have are near the thermostat housing, the one with a single wire is the gauge sensor. The one with a square top is the ECU temp sensor, which is reported to the OBDII port.

My 97 will make 183-185 at freeway speed with AC on, 85F outside. 180F stat.

A short to ground on the cables will make gauge read strange.

 

They are the ones!! No, I still need to get a scan tool.

 

Water pump / fan clutch?

 

head gaskets? bad ? expansion tank or cap ? there's only so many components on the cooling system

 

For a test, try taking a battery jumper cable from the negative battery post, and connect other end to the engine block. See if that changes things with the gauge jumping and turn signal. A missing ground strap can do strange stuff.

You might also check charging voltage, should be 13.8 - 14.4. Maybe your problem is related to low battery voltage at idle, and this goes away at higher rpm. In other words, the amps drawn by the blinkers should not overwhelm the alternator and make battery voltage change a bunch.

Was new thermostat installed with sprring end poking inside the block? If you had a hole or jiggle device in the flange, it should be at the 12:00 position to allow steam pockets to pass. And could be a bad stat. About $10 at parts store. You can test in a pot of water on the stove.

 

I have lite ticks with the blinker on so if you figure that out let me know I figure a bad or loose ground somewhere

 

My temp gauge will move up & down slightly with the turn signals. Quite amusing, really. Yet another reason to like the Ultragauge.

 

Definitely check the expansion tank cap. Mine lost all pressure in 2 seconds flat when I tested it. Blew me away how simple a fix that was!