SteveG S4

Normally my oil temp gradually increases as the car warms up, stabilizing somewhere under 250 degrees. Lately I've noticed the temperature occasionally going up to around 300. But today it went totally wacky on me.

Glanced down and noticed temp was around 300, cruising at a steady 75 mph in 6th gear, on a 60 degree day. No way the oil should be that warm. Then the temp climbed to around 325 (one tick shy of the right edge of the guage!), and then slowly (in a matter of minutes) fell back down to around 275. Then later it went back up to 325, and I watched it then fall to 225 in a matter of just 20 seconds or so! I mean, the needle just made a smooth sweep of 100 degrees in a matter of seconds. After that, it stayed around 225 for the rest of the trip (30 minutes).

So what do you think - do I have a bad oil temp sensor, or is something else wrong that is actually making the oil temp swing like that? Other info - oil level is fine, but I am due for an oil change - nearing 5000 miles on Mobil 1 5W-30.

Nick Gustas

Bad sensor.