Low oil pressure

[flyboyron]

My 2009 Silverado with the 5.3L V8 has always run well, and I am always driving it easy.

This is the normal oil pressures I read on the gauge whether or not how accurate it is.

Cold Idle 35psi

Before the engine is fully warmed up at 2,000 rpms the oil pressure is at 60psi.

Engine warmed up at 65 mph the rpm is at 2,000 oil pressure settles down about 40psi.

I noticed this week the following...

Cold Idle 30psi

Before the engine is fully warmed up at 2,000 rpms the oil pressure is at 35psi.

Engine warmed up at 65 mph the rpm is at 2,000 indicating about 30psi.

The oil pressure indicator never got over 40psi no matter rpm I was at.

I checked the oil level on the dipstick and it read at the 1^st dot. I guess that is ¼ of a quart low.

This oil pressure seemed low to me.

I thought maybe the oil viscosity was compromised because the oil has about 7,000 miles on it, showing 30% oil life remaining and I usually change it when it gets down to about 10 – 15% remaining.

So I went and had the oil changed to see if that had any effect on the oil pressure and yes, it did. The oil pressure is now back to normal.

I would have never thought the oil viscosity would change as the oil gets older.

I had the last oil change done at the dealer, and was wondering if this is because the dealer used a cheap oil.

Before these Oil Life Remaining gadgets, I changed the oil in my vehicles every 5,000 miles. The truck is supposed to use 5w-30, and I never thought the oil pressure would drop when the oil gets more than 5,000 miles on it.

Any ideas?

[swathdiver]

This has been my experience as well.  In addition, I've noticed lower oil pressure with certain oil filters, like the Mobil One Extended Performance filter drops my pressure about 3 psi compared with the K&N with the 1" nut welded to the end.  I change my oil at around 5000 miles which usually says about 30-35% on the OLM.

 

Do you have an LC9 or LMG?  My truck has the former.

[garagerog]

I'm sure some of the oil experts will weigh in on this, but it's my understanding that as oil accumulates miles, the add pack wears out including viscosity modifiers. With increasing mileage the stated viscosity range moves to the lower end of such range resulting in "thinner" oil and lower oil psi.

[flyboyron]

3 hours ago, swathdiver said:

This has been my experience as well.  In addition, I've noticed lower oil pressure with certain oil filters, like the Mobil One Extended Performance filter drops my pressure about 3 psi compared with the K&N with the 1" nut welded to the end.  I change my oil at around 5000 miles which usually says about 30-35% on the OLM.

 

Do you have an LC9 or LMG?  My truck has the former.

I am not sure!  I see that I have the 5.3J (LY5) with the 4L60E transmission.

[swathdiver]

20 hours ago, flyboyron said:

...I have the 5.3J (LY5) with the 4L60E transmission.

Ok, forgot about that one.  It's an iron block motor and those pressure are good for an iron block.  The aluminum block engines, because of their greater tolerances, run less oil pressure at a higher volume.

[carnau]

On 5/8/2020 at 1:36 PM, flyboyron said:

My 2009 Silverado with the 5.3L V8 has always run well, and I am always driving it easy.

 

This is the normal oil pressures I read on the gauge whether or not how accurate it is.

 

Cold Idle 35psi

 

Before the engine is fully warmed up at 2,000 rpms the oil pressure is at 60psi.

 

Engine warmed up at 65 mph the rpm is at 2,000 oil pressure settles down about 40psi.

 

I noticed this week the following...

 

Cold Idle 30psi

 

Before the engine is fully warmed up at 2,000 rpms the oil pressure is at 35psi.

 

Engine warmed up at 65 mph the rpm is at 2,000 indicating about 30psi.

 

The oil pressure indicator never got over 40psi no matter rpm I was at.

 

I checked the oil level on the dipstick and it read at the 1^st dot. I guess that is ¼ of a quart low.

 

This oil pressure seemed low to me.

 

I thought maybe the oil viscosity was compromised because the oil has about 7,000 miles on it, showing 30% oil life remaining and I usually change it when it gets down to about 10 – 15% remaining.

 

So I went and had the oil changed to see if that had any effect on the oil pressure and yes, it did. The oil pressure is now back to normal.

 

I would have never thought the oil viscosity would change as the oil gets older.

 

I had the last oil change done at the dealer, and was wondering if this is because the dealer used a cheap oil.

 

Before these Oil Life Remaining gadgets, I changed the oil in my vehicles every 5,000 miles. The truck is supposed to use 5w-30, and I never thought the oil pressure would drop when the oil gets more than 5,000 miles on it.

 

Any ideas?

 

Was a GM filter used? You could have some trash in the screen and when you removed the oil filter the oil drained down and out from the oil pressure sensor passage. If it does it again, I would recommend removing the oil filter, oil pressure sensor, replacing both filters and cleaning the passage out. You can do that by following this video.

 

Also, Anywhere in the cross stitched area is considered full. So the first dot on this vehicle is actually full. It could have oil trapped on top of the heads causing it to not be higher than where it was showing.

 

If the oil is below the cross-hatched area at the tip of the dipstick, add at least one quart/liter of the recommended oil. This section explains what kind of oil to use. 

Normal oil level is anywhere between the cross-hatched area.

 

 

 

 

[flyboyron]

That dipstick is not correct. I looked in my manual and it shows the same one you put here, but my truck has a different one.

I took a picture of it and attached it to this reply. Mine only has 4 dots and not 5.

Years ago they used to be like the one showing in the manual but mine has one less dot. I guess they removed it to save money.

I could never figure out where exactly 1/4 qt is, or even half quart low, but made general assumptions. So now maybe they went to 1/3 quart low at the second dot from the top, and then 2/3, and then 1 Qt at the last dot.  Or maybe its in ounces. The first dot 10oz, the second 20oz, and the bottom dot 30oz, close to 1 quart. Who is going to argue over a couple of ounces here or there. Yes the top dot is full.

Thanks for posting the video. I had heard about that procedure and knew if the oil pressure did not come up with an oil change, I would have to look into having that done.

Everything is fine now, the oil pressure is where it has been in the past.