Was out on the Hassayampa yesterday in the sand and when pulling back onto the shuffleboard dirt road to head out, I noticed the temp gauge was flickering up and down from mid-point (normal temp) to HIGH - very unusual. Sand was fairly hard packed, and not a lot of bogging/slippage.
I immediately pulled over, and noticed that when the engine went to idle, the Temp Gauge needle immediately went to mid-point (normal) and was rock steady. Just to be sure, I opened the hood and checked overflow bottle, radiator cap, and saw no signs of overheating, whatsoever. Oil pressure was normal and level topped off before our last club meet, but checked that again to be sure - no problems there. Engine fan was working fine and pulling plenty of air through the radiator, no CEL, no loss of power, no signs of overheating. I wasn't running A/C either.
Got back on the road and noticed that if I accelerate, the Temp Gauge will peg to the HIGH range, and as soon as I let off the gas pedal, it immediately drops back to rock steady at the mid-point. Drove it gingerly across Carefree Hwy back toward I17, and replicated the behavior under steady state cruising (cruise control set at 2k RPM = 60mph). If you watch the needle, it actually ticks as it bounces off the HIGH limit within the gauge, flickering at a high rate as if it's mounted on a spring. Let off the throttle and coast = goes back to rock steady at mid-point. Step on the gas, and it pegs the needle at HIGH.
Took a good look at everything when I got home and nothing out of the ordinary. Checked it again on a trip today (freeway speeds), and exact same behavior. No other engine work has been done, haven't topped off the radiator recently (thinking air bubble near the sensor), and checked it multiple times today to be sure it's not overheating - and it's definitely not.
Thinking this is a Temp Gauge sending unit failure, but wanted to check with the group. Scheduled oil and filter changes, new head gasket over 5k miles ago, and the PO replaced the silicone oil in the engine fan for PHX temps years ago.
Any tips/suggestions/concerns appreciated,
I immediately pulled over, and noticed that when the engine went to idle, the Temp Gauge needle immediately went to mid-point (normal) and was rock steady. Just to be sure, I opened the hood and checked overflow bottle, radiator cap, and saw no signs of overheating, whatsoever. Oil pressure was normal and level topped off before our last club meet, but checked that again to be sure - no problems there. Engine fan was working fine and pulling plenty of air through the radiator, no CEL, no loss of power, no signs of overheating. I wasn't running A/C either.
Got back on the road and noticed that if I accelerate, the Temp Gauge will peg to the HIGH range, and as soon as I let off the gas pedal, it immediately drops back to rock steady at the mid-point. Drove it gingerly across Carefree Hwy back toward I17, and replicated the behavior under steady state cruising (cruise control set at 2k RPM = 60mph). If you watch the needle, it actually ticks as it bounces off the HIGH limit within the gauge, flickering at a high rate as if it's mounted on a spring. Let off the throttle and coast = goes back to rock steady at mid-point. Step on the gas, and it pegs the needle at HIGH.
Took a good look at everything when I got home and nothing out of the ordinary. Checked it again on a trip today (freeway speeds), and exact same behavior. No other engine work has been done, haven't topped off the radiator recently (thinking air bubble near the sensor), and checked it multiple times today to be sure it's not overheating - and it's definitely not.
Thinking this is a Temp Gauge sending unit failure, but wanted to check with the group. Scheduled oil and filter changes, new head gasket over 5k miles ago, and the PO replaced the silicone oil in the engine fan for PHX temps years ago.
Any tips/suggestions/concerns appreciated,