Oil Pressure Gauge Extremely High After Cold Start

[Colt]

I have 2001 GMC Yukon SLT 5.3L. When I first start it in the morning and accelerate the oil pressure gauge will increase pass 80psi. After running for a while it will come back down to 40psi at idle and a little under 60psi when accelerating. Is this cause for concern or sign of something I should be aware of?

 

[bill1013]

On a cold start the oil is very thick and viscous so the pressure reads, and is, a little higher. As the engine warms up the oil gets thinner and the pressure drops down to normal. An example would be in Canada. My 1999 Tahoe was originally from Manitoba, Canada and it had a piece of metal, with an AC electrical cord that led up towards the battery then 12 ft. coiled up. The cord was to be plugged into an AC electrical outlet. It heated the piece of metal, or blanket as I liked to call it, which in turn keep the oil from getting too viscous or congealed. If the oil gets too thick the oil pump can't supply enough oil to the cylinders at start up. No oil would cause the engine to seize up. Hope this helps. Aloha!!

 

[Fless]

You might want to put a manual gauge in place of the sensor to verify the actual pressure; the sensor or the gauge could be malfunctioning.

Any history with work on the oil pump?

 

[Colt]

You might want to put a manual gauge in place of the sensor to verify the actual pressure; the sensor or the gauge could be malfunctioning.

Any history with work on the oil pump?

No, I've never had any problems with the oil pump. I'll definitely look into the manual gauge to see if I am getting accurate readings though. Thank you!

 

[Colt]

On a cold start the oil is very thick and viscous so the pressure reads, and is, a little higher. As the engine warms up the oil gets thinner and the pressure drops down to normal. An example would be in Canada. My 1999 Tahoe was originally from Manitoba, Canada and it had a piece of metal, with an AC electrical cord that led up towards the battery then 12 ft. coiled up. The cord was to be plugged into an AC electrical outlet. It heated the piece of metal, or blanket as I liked to call it, which in turn keep the oil from getting too viscous or congealed. If the oil gets too thick the oil pump can't supply enough oil to the cylinders at start up. No oil would cause the engine to seize up. Hope this helps. Aloha!!

That makes sense about the oil being more viscous at start up. Hopefully that's all it is. Thank you!

 

[Fless]

Does your gauge sit at about zero with the key on but engine not running? Or with the key off?

The numbers, if true -- and I think it would be odd that they are actual -- are concerning.

 

[Colt]

Does your gauge sit at about zero with the key on but engine not running? Or with the key off?

The numbers, if true -- and I think it would be odd that they are actual -- are concerning.

After I turn off the vehicle the oil gauge will stay at about whatever it was when the engine was running. When the engine is off and I turn the key to the on position the gauge will reset and be at zero then it will go to a little over 40 when I start the engine.

 

[clandr1]

Welcome to the forum. Here are some questions to help me understand some variables:
Where are you located (city/state)?
What oil are you using (brand, weight, etc.)?
What is the ambient temperature when this occurs?
How long have you had the truck?
How many miles have you put on it?
How many miles total are on it?
Did an oil change take place shortly before you experienced this issue?

 

[Colt]

e Welcome to the forum. Here are some questions to help me understand some variables:
Where are you located (city/state)?
What oil are you using (brand, weight, etc.)?
What is the ambient temperature when this occurs?
How long have you had the truck?
How many miles have you put on it?
How many miles total are on it?
Did an oil change take place shortly before you experienced this issue?

The truck has spent most of it's life in Virginia/Tennessee. I am currently in Nashville Tennessee. I have been using Pennzoil 5W-30 High Mileage in it since I got the truck. I started seeing this occur this summer so it's been about 80 90 degrees outside. I got the truck last December and it had 151,000 miles on it. It is currently sitting at 166,870 miles. I started seeing the problem a few weeks ago and have since changed the oil and oil filter. Since changing the oil though there has not been any changes to the erratic readings. I think it could just be a bad oil pressure sending unit but the fact that after the truck runs awhile the readings return to normal makes me wonder.

 

[Fless]

I'm suspecting the gauge itself, since it stays in place when you turn off the ignition. At that point the sender isn't powered, but I suppose there could be some kind of problem in the circuit.