K-temp -128 in cluster?? (FIXED)

mam4.6 · #1 01-25-2016, 02:10 PM

Hey, fellow X'ers. Haven't posted in awhile, but I lurk daily. Got a new issue that came up. One of my coolant hoses split the other day, so I reinstalled it, and filled it back up with coolant/distilled water and led the system. The only problem is that my temperature needle stays pegged above red, and the ktemp readout says -128. The only conclusion I've come to is that there is an open circuit somewhere, and both readout are in their default positions. But I thought the items readout and the needle got their info from separate sensors? Where do I start looking?

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David.X5 · #2 01-25-2016, 02:40 PM

Did you check the electrical connectors (temp sensor and thermostat) on the water pump and thermostat were all put back and fully seated? Seems like the place to start.

mam4.6 · #3 01-25-2016, 07:14 PM

Checked all of that, unseated and reseated, to no avail. Is there a chance the sensor just sent bad?

David.X5 · #4 01-25-2016, 08:12 PM

hmmm. not an easy one.

So, yes, I have no problem imaging you have a defective temperature sensor. It happens.

I would check the grounding first - do you have good ground between the block and frame (the ground strap is in front of the right front wheel, attaches to (or near) the motor mount. Second is the mounting of the sensor itself - any chance you used rtv / antisieze / teflon tape that might be interfering with the ground connection?

The good news is that the sensor can be replaced without dismantling the water pump and thermostat assembly...

mam4.6 · #5 01-25-2016, 10:26 PM

Thanks for the suggestions. I'll make sure and check the grounding before continuing with anything else. No, I haven't used anything on the threads, either. Should be fairly simple to swap out the sensor, as I have one laying here. I'll try that this week sometime...

mam4.6 · #6 01-26-2016, 05:13 PM

So I replaced my double temp sensor, the one that screws into the block. Still does the same thing. I did notice my lower radiator hose isn't getting hot. So?? Could it be I have a bad thermostat? It was replaced with an oem piece less than 2 years ago...

bcredliner · #7 01-26-2016, 05:54 PM

There may still be air in the system or the coolant could still be low. Won't hurt to bleed the system again.

mam4.6 · #8 01-26-2016, 06:13 PM

Would you drain again? I've open the cap and cycle the heater valve, revved the engine, etc, the normal steps for bleeding, and can't get any more bubbles in the expansion tank.

mam4.6 · #9 01-26-2016, 06:19 PM

I might add I'm getting good cabin heat...

bcredliner · #10 01-26-2016, 06:23 PM

Quote:

Originally Posted by mam4.6

Would you drain again? I've open the cap and cycle the heater valve, revved the engine, etc, the normal steps for bleeding, and can't get any more bubbles in the expansion tank.

No, top off the coolant, bring the engine to temperature with the heater at max heat, leave the cap on and open the bleed screw which is new to the expansion tank cap. Leave it slightly open wait until no bubbles come out. You are getting heat from the heater?

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