Oil pressure went nuts

[Snow Shovel]

I have a 2004 Silverado 2500HD, 4wd, 6 liter gas engine. Manual transmission; 105,000 miles.

 

Friday I was at work in the parking garage and noticed I had no oil pressure. Engine was running fine, but I stopped, made sure I had oil in the engine and looked for massive spillage. Everything looked good, so I started it up again and it went right to 40 pounds. It acted right the rest of the day.

 

Saturday on the way back from the dump I noticed 80 pounds of pressure and climbing. Changed the oil and it looked good. No antifreeze in the oil, no grit, no shavings on the magnetic plug. After I changed the oil, pressure came back to 40 lbs and I felt like I had fixed it.

 

Sunday nothing abnormal noted.

 

Monday driving to work, about three miles into the drive, and I have 60 pounds and climbing. I have a 5 mile drive total and by the time I got to work, it was 80 pounds and climbing. On the drive home the needle kept moving clockwise until it was way past 80, all the way to the 5 o’clock position.

 

When I turn the key all the way on without starting the engine, I can hear relays under the hood clicking. Don’t know if they have always done this, but now I notice it. When I turn the key off, the oil pressure gauge needle either stays where it was or it will move a little counter clockwise; it does not move all the way counter clockwise and park itself like the other gauges. Throughout all of this the engine runs fine, no smoking, clanging, not so much as a minor throttle fluctuation.

 

So I am guessing an electrical problem between the engine and the gauge. Any idea what I should check? Thanks.

[Snow Shovel]

OK. I managed to goof up this post. Meant to put it under "technical". I will do that now.

 

Guess at 4 am the coffee just isn't strong enough.