Hi, gang:
The oil pressure gauge in my 89 Caravan 3.0 has been reading goofy (and generally lower than I'd like) for a few months, now. The whole mess seemed to be triggered by a local shop that put 5W-30 into the engine during an oil change, when I've been running 10W-30 or 10W-40 for years. Before that oil change, no issues with the oil pressure gauge AT ALL. After the change, on the same day, I noticed that the pressure reading dropped when I was cornering at very low speeds. I can't prove it, but the coincidence seems odd. Fine for five years, then goofy starting 15 minutes after the oil change in question...
Sometimes, when I come to a stop after the engine's warm, the oil pressure gauge will plunge. It doesn't do this when it's cold -- and in Minnesota, it's COLD!
Last night, when I drove to work, about 6 blocks before I arrived, the oil pressure gauge dropped to nothing. As I was slowly driving the rest of the way, the needle would occasionally climb up a bit, then drop off to nothing again (triggering the "check gauges" light on the dash).
After work I topped off the oil (half-a quart below full) and fired up the beast. As it has been for the past few months, it started and ran fine, despite the fact that there was now NO READING from the OP gauge at all. I drove home 10 miles at 30-40 MPH, got home and parked, and listened to the engine. It was smooth-sounding and seemed to be running just fine (as it had all the way home).
QUESTION: If there truly was no oil pressure, wouldn't the engine start to clatter?
I hope like hell it's the sending unit. I'm trying to find a buddy with a manual pressure gauge...but I have to drive back to work in the morning. :)
Any ideas?
Thanks, as always,
--Kirk in MN
P.S. It really sucks working on the car when the wind chill is 40 below zero...