low oil pressure

woodbutcher

Well-known Member
I bought my 2013 GMC Sierra 1/2 Ton, 2WD with 5.3 engine new in 2013, and the oil pressure gauge showed low readings from day one. When it was cold it would show less than 40 psi, and after warm-up it was down around 30. I have 35K miles on it now, and oil pressure readings are probably 30 psi at best. The factory gauge doesn't show numbers, so I'm guessing. I'm hoping the O-ring on the pickup tube is the problem. Replacing it would be easier than replacing the pump, but I'll probably hire it done. Does anybody have experience in comparing the cost of this job to doing the oil pump replacement at the same time?

Butch
 
Those don't run very high oil pressure.

That's about what mine runs, same same truck, same engine.

I've never looked up the specs, but everyone told me not to worry, that's normal.
 
I ordered my Ford Club Wagon new in 1990. Always changed oil every 3k miles. After about 150k miles I noticed the pressure getting slightly lower as the years passed. I knew (from decades in the business) that Ford bearings were "softer" (some may argue this) and resigned myself that even though I kept up on oil changes the engine just plain wore down. Before pulling the bottom end off the engine I decided WTF, I'll try a new oil pressure sender first. Pressure went back to like when it was new. May be worth a try.
 

old adage I've always heard is you only need 10psi for every 1000 rpms the engines turn.

I had to put a new 5.7 in my 2008 suburban and brand new it only ran 30 psi at idle and about 40-45 at high speed... mechanics tell me that's plenty.. BTW I use Mobil 1 and change at 5k

john
 
Same truck, year and engine here. 38 psi at highway speed, warmed up in the summer when new. 122,000 miles on it now, has dropped to 36 psi. Also use Mobil 1.

I wouldn't worry about it.
 
remove the oil sender unit and see if the screen is plugged.
Chevy Engine Oil Pressure Sensor


The Chevy engine oil pressure sensor problem has been going on for a long time. With that said, the vehicles with the most pressure switch problems fall in the range of V-8 engines from 2003 through 2012. At some point in the model year of 2007, Chevrolet realized an issue existed.

They decided to place a filter screen around the Chevrolet engine oil pressure sensor. They did this because they believed sludge and debris found its way into the sensor. Not only did this not fix the problem, it created another. Now sometimes when you pull the protective filter screen out, you find it completely clogged.
 
Did you check the pressure with a mechanical gauge? In nearly 50 years as an auto tech I replaced a lot of sending units. By the way an mechanic gets paid for his labor but a tech gets paid for his knowledge! LOL We all start as mechanics !
 
Most of the Onan engines. Start at 40-45 pounds. When hot drop to 30-38 pounds. I would guess that would be a normal range on that engine.
 

Crank driven oil pump on my 6.0 failed on startup .replaced the plump with a high volume unit from Chev racing division .
Holds 30psi at idle 284$ over 200,000 on the engine .
 
I'm using full synthetic Castrol. The oil pressure never concerned me too much, but it is lower now than it used to be.
 
I have a 2010 Sierra 1500 with the same engine. About 80,000 miles or so on it.

I just got home from about an hour's drive and the oil pressure drops just below 40 at an idle and gets to between 40-50 while driving. Synthetic oil. That hasn't changed in the 10 years I've owned the truck.

Those engines will use some oil on highway drives when the computer shuts down cylinders. I forget the details why, but there is a fix you can do. You can google it, there are a lot of sites that can tell you about it. I usually just add a quart between changes, that's cheaper than the fix.
 
Comments about the sending units reminded me. Remember when graphite oils came out around 1980? I started using it in my Scout and 76 Plymouth 360. After a few months the oil pressure on the Scout was gradually dropping. The Plymouth oil light came on earlier and earlier when slowing down till it stayed on at 35. I put a mechanical gauge in place of the sender and it was 40 at idle. Stopped using the s**t and they both eventually came back to normal. That stuff didn't stay on the market long.
 
I have a 2000 with the 5.3 engine, 216,000 miles on the clock. It holds 60 lbs oil pressure on the road--when the oil is fresh.

When the oil has several thousand miles on it, the pressure drops to 40 on the road. It's always been that way.
 
What oil filter are you running? Certain brands tend to lower the oil pressure. Try a wix or napa filter. I've had 2 different trucks do it with 2 different brand filters. Ac delco was one of them, but I've also run delco successfully. Luck of the draw i think.

Those 5.3 engines also have a second pressure relief to lower the oil pressure to the valve train for the active fuel management, so the probably never show real high to start.
 
I don't know if they are the same but my 2013 6.0 only reads about 40 psi cold. At highway speeds it drops a couple and drops a couple more at hot idle.
Had two 6.0s before this one and they read about the same. Both went to 200K before I traded.
Here's an idea I had and have wondered about:
Could GM have reduced oil pressure as a means of increasing mileage? It takes more energy to produce and hold 50 psi than it does 40 psi. In these times of extreme efforts to maximize mileage maybe?
 
Those engines have variable valve timing that uses a oil pressure operated solenoid. When the system has problems the oil pressure can drop and excessive oil can spray up on the cylinder walls and cause oil consmuption bacause they use a high volume oil pump.
 
Use a WIX 7045 and your pressure will increase. The oil pickup o'ring is an old wives tale with the 5.3. They did have some issues pinching that ring on assembly in 1999, never seen it since. I've been around the LS engine since the beginning, worked at a GM dealer then.
 
GM gauges are notorious for poor readouts for the past 15 years - rebuilding the entire gauge panel on everything from Impalas to pickups has become quite the cottage industry.
 
The number has me confused, Sprint. I ordered two Wix 57045XP from Amazon, and I hope I didn't make a mistake. All the Wix charts call for Wix 57060 on this pickup. Will the 57045 work?

Butch
 

cvphoto71326.jpg

57045 is a longer oil filter than original. It will fit fine, and presumably will have more filter media in it. I use them on my 5.3 and 6.0.
 

If you have only been looking at the dash oil pressure gauge that has no numbers, how is it you came up with the numbers you posted??
You might be worrying about nothing.

A real mechanical gauge might even show higher pressure than recommended.
 
The stock gauge has a 40 centered on it with lines that divide the rest of the face into equal spaces. It's just a guess as to what the actual reading would be. Yes,
a mechanical gauge would be more accurate.

Butch
 

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