Temp gauge pegged

[Jethro Tull]

I took my '91 Explorer to the car wash to de-grease the engine, as I do about once a year for the past 19 years (I bought it BN).

This time, as I started it up to drive off, the temp gauge just moved all the way over to the right and stays pegged there.

The engine was cold at the time and the gauge was in the normal postion on the way to the car wash (only a couple of blocks from home). It's running perfectly as near as I can tell.

Obviously some water got into a connector somewhere and has caused a short...any ideas? Think this will dry up and fix itself? Or could there be something damaged that I need to replace? First time in all these years it's ever happened.

Thanks!


4.0L V6 5 spd. MT

 

[BrianDye]

Anything you do special? I wanna do that too, mines so dusty, and im scared that ill short something out or mess something up...

 

[Jethro Tull]

Remember that the engine compartment is open on the bottom as well as large portions of the front, so rain and road water get in there all the time.

Usually I just use the high-pressure wash wand, soap first, then rinse. When it's really greasy, like this time (I had some PS line leaks and it was pretty messy) I warm up the engine then spray on some regular kitchen oven cleaner. Give it a few minutes to work then the high-pressure soap spray followed by a good rinse. It's a good opportunity to do the PS lines behind the front wheels, as well.

Nothing bad has ever happened in all these years until that darn electrical short today. I'm hoping that it dries out on it's own.

I wash the engine bay on my Subaru and Mazda the same way, no problems.

 

[explorerguy89]

could have shorted the wire for the temp sender which is next to intake on top of the motor

 

[Jethro Tull]

could have shorted the wire for the temp sender which is next to intake on top of the motor

Thanks! If it doesn't clear itself up when I turn it over tomorrow, that's the first thing I'll check. Getting too dark to do much good out there today.

 

[shaggymane]

Mine started doing that too but not after washing. After sitting for the night it would peg the temp gauge all the way to hot and then slowly come down to normal as the engine warmed up. Since there's no way that could be accurate I just changed the sending unit.
Works properly now. After 155K sensors are starting to go.

 

[Jethro Tull]

I went out and started it up today, drove to the gas station and filled it up. The gauge is it's old self again, working perfectly. Whatever water got in there and caused the short evaporated overnight.

Once the weather gets warmer, I may change the sending unit and check the connector just because, as shaggymane noted, it's time.

BTW, even after 19 years and 128,000 miles, I still get 19-20 mpg from this vehicle. I do buy mid-grade gas because she knocks with octane below about 89.