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.

[jhm]

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.

I would guess a sensor. I had something smilar this morning. It is 10 degrees outside, has been for days, and as I was driving I noticed the oil pressure pegged at 70. Made no diff if I sped up or slowed down. No engine noise, ran fine. I am waiting to see if it changes today.

[hardav]

I would first replace the oil sending unit> It is located at the rear of the engine, approximatly center to drivers side center. Can be a pain if you have big hands. You will need an oil sending unit socket,($5) you need the 1 1/16" socket. these sockets are made specifically for the sending unit, a socket out of your tool box will not work. A 3 to 6 inch socket extension will really help also.

the Sending unit is about $40.

It sounds like a sending unit problem so fot Less than $50 you could have it fixed.

Good Luck