High oil pressure - failed sending unit?

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Jul 14, 2020
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Driving this morning I assumed I lost next gauge on my defective instrument cluster (2005 Silverado - normal problem). The tach and fuel and oil pressure were the last remaining functioning gauges. I looked over to verify normal oil pressure on torque pro and it read over 80 psi.
 

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What weight oil? Warm or cold engine? What is the engine speed?An oil pump issue can cause high pressure. I would further test with an actual pressure gauge installed before coming to any conclusions.
 
You should never snap a pic at 200 plus MPH! ;)Nothing mechanically wrong here. Your instrument cluster stepper motors are giving up the ghost. My 2005 was doing the same and I took the cluster (easy to remove) to my local speedometer shop. $200 for a total rebuild, (back to me in 1 day) and has worked like new for the last 3 years. (y)
 
You should never snap a pic at 200 plus MPH! ;)Nothing mechanically wrong here. Your instrument cluster stepper motors are giving up the ghost. My 2005 was doing the same and I took the cluster (easy to remove) to my local speedometer shop. $200 for a total rebuild, (back to me in 1 day) and has worked like new for the last 3 years. (y)
I assumed that was the case as the gauges are all failing one by one but the other picture of torque pro proves that not the case on this one.
 
What weight oil? Warm or cold engine? What is the engine speed?An oil pump issue can cause high pressure. I would further test with an actual pressure gauge installed before coming to any conclusions.
0w40. Yesterday hot idle oil pressure was 34psi and now it's about 78. Over 90 at cruise rpm.
 
By looking at the other gauge readings ........I would assume the oil pressure gauge doesn't work right either .
 
Let's just pretend we didn't see the instrument cluster and look at the data from the ECM. It actually seems to be getting higher and higher. It was around 80 at idle when I first noticed the issue and now it's 108 psi at 546 rpm. Climbing to over 120 at cruise.
Sending unit or oil pump issue?
 

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Let's just pretend we didn't see the instrument cluster and look at the data from the ECM.
OK, I see what you’re saying now. Those are some high OP readings for sure. My 05 5.3 is at about 50 psi on cold start and around 45 at hot cruise.
Sending unit or oil pump issue?
You’re on the right track.
would further test with an actual pressure gauge installed before coming to any conclusions.
Plus, what Lubener said.
 
OK, I see what you’re saying now. Those are some high OP readings for sure. My 05 5.3 is at about 50 psi on cold start and around 45 at hot cruise.

You’re on the right track.

Plus, what Lubener said.
It's almost for sure the sending unit because it eventually became permanently stuck at 134.6 psi on my drive home. It never moved from there until I shut it off and restarted and it went back to 107 at idle.
Normally it's same as yours, 50 cold start and 45 hot cruise. 33 at idle give or take.
I'm going to order a sending unit for it and the little adaptor gasket that's leaking also.
 
I will try to get a mechanical gauge on it, when I have the sending unit removed, so I know for sure what it is.
 
Replace the sending unit, Extremely common on '03-'13 GM trucks. As failure prone as OE sensor are....Aftermarket ones are worse!

No AFM Solenoid Screen on a 2005 model.
Well this one at least lasted 235k miles and 10,300 hours, as far as I know. I ordered an OEM Ac Delco sender along with fel pro oil filter adapter gasket and a Mahle oil pan gasket so I can remove it and inspect/clean the pan while I'm at it.
 
Not saying it's impossible for one to last that long.

Change the pick-up tube O-ring while you're in there. If you're chasing an oil leak.....The Rear Engine Cover Gasket is likely leaking, On a 4x4 GMT800, It's easiest to yank the engine & do a complete re-seal. 2wd's can be done pretty easily with the engine in the truck & pulling the transmission.
 
Not saying it's impossible for one to last that long.

Change the pick-up tube O-ring while you're in there. If you're chasing an oil leak.....The Rear Engine Cover Gasket is likely leaking, On a 4x4 GMT800, It's easiest to yank the engine & do a complete re-seal. 2wd's can be done pretty easily with the engine in the truck & pulling the transmission.
I would if I could but it's a 4wd and I don't feel confident attempting that on my own. I've been watching the oil pressure like a hawk and it hasn't changed in the past 2 years so I'm hoping I won't have the oil pump o ring issue. It only appears to be leaking at the oil filter adapter gasket as far as I can see. I might not end up doing the oil pan until the summer anyway. I get to do this work laying on soaking wet concrete with slush falling down on me off the truck.
 
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