HOW TO: TEST & FIX LOW OIL PRESSURE IN YOUR 5.3L OR OTHER LS?

STEP BY STEP-TEST AND FIX LOW OIL PRESSURE ON MY 2002 5.3L (1500 SILVERADO) WHY IS IT LOW? WHAT COULD IT BE? ELIMINATE THE POSSIBILITIES. START WITH THE EASY STUFF. WORK TO THE MORE DIFFICULT. WE LOOK AT OIL LEVEL, OIL PRESSURE SENDING UNIT, CHANGE VISCOSITY, CHECK FOR BEARING WEAR OR DAMAGE. WE EVEN COVER OTHER POTENTIAL CAUSES, BUT FINALLY SOLVE THE QUEST FOR PRESSURE MYSTERY. CHECK OUT WHAT IS WAS AND HOW I FIXED IT-WORKS ON JUNKYARD MOTORS TOO!

[jakematthews]

I worked with a guy who condemned 5 LS based engines for low oil pressure. Each engine was replaced with either new or rebuilt. The tech ALWAYS ended up with the old engine. He’s then replace the CORRECT part to replace, and sell the engine and pocket all the cash. When I let the service manager know, I’m the one they reprimanded. People like those guys make good mechanics look really bad. If you’re in the Boise Idaho area and you need automotive work done, call around. If someone named Rocky answers the phone, don’t go to that shop.

[reevinriggin]

Changed an LS oil pump on a very similar truck with a 5.3L that had 408, xxx miles and it was just flat worn out. Not to mention the exact same O-ring on the pickup was also cracked. This particular truck had less than 10psi at idle. No engine problems noted. Oil pressure restored and it is still running to this day. These are really good engines. And that is coming from a die hard SBF fan.

[ddforrester]

I changed the engine oil in my 2013 GMC Sierra a week ago. I've had this truck for over two years and have grown accustomed to where the oil pressure guage rests throughout the warming cycle and normal operation.
This time I used the usual Pennzoil 5W-30 Platinum Full Synthetic along with a new-to-me ACDelco PF48E filter that was available locally. I usually have a couple Wix 57060XP on the shelf but had run out and couldn't find one locally.
I drove to work the next day and at the first traffic signal I noticed my oil pressure guage reading a bit lower than usual. The truck is usually at 30-35 PSI idling in drive and 40-45 driving at 1.5k-2k RPM. But now it was 18-20 PSI idling and 22-26 PSI while driving.
I started watching YT videos trying to diagnose the oil pressure issue myself. I added a drop of Lucas Oil Stabilizer, no change.
I dropped the oil pan (pain in the rear) and changed the fabled o-ring, no change.
I bought a new oil sending unit. Before replacing that I decided to pause and ask...
WHAT CHANGED?
AHH. The oil filter was a different brand. Maybe that's it?!
This morning I climbed under the truck with a drain pan and swapped out the brand new ACDelco PH48E with a brand new Wix 57060XP filter. Topped off the oil and started the truck up.
Dog gone it! The truck was BACK to the normal oil pressure readings of 30 - 45 PSI.
I don't know if the new ACD PF48E had a bad check valve or the media was too restrictive...
Fellers, if you find yourself parts-cannoning after a similar situation stop first and ask yourself: WHAT CHANGED?
I'm relieved that my truck isn't busted and it was a simple oversight.
I hope this helps someone out there.

[kid]

my dads 04 chevy silverado has a 5.3 ls motor and some years back it started reading low oil pressure but then the volt meter started acting up and then i did some research and found out that the instrument clusters in gm cars and trucks had some serious issues, so i went to my local napa dealer and got another updated cluster and the oil pressure issue was solved i really appreciate you showing us how you figured out your issue thanks for that!

[stevelacker]

1) so glad you didn’t just say “10 psi per 1000 rpm, that’s good enough.” :) Sure that’s fine for some engines, but when you see a sudden change, the fact that it CHANGED is much more important than the actual pressure.

2) Weirdest one I ever had was on a 440. As you know they have an external oil pump and the oil pressure regulator is built into the pump cover. The cover is an iron casting that incorporates the filter mount, and internallyhas a machined passage with a spring-loaded piston that lifts at the set pressure and dumps excess oil from the pump outlet to the pump inlet (remember this for later...). This particular engine had lost an engine mount, shifted sideways, and bumped against the subframe (which I didn’t know at the time). I fixed the mount and drove a few weeks with no issues. Then one day, as everyone with a big block will occasionally do, I let ‘er rip to redline through first gear and enjoyed the screech when it shifted to second. But when I Iet off at cruise speed, I had about 30 psi instead of the usual 65. At idle it was less than 10 instead of the usual 25. Uh oh. I decided to change the oil and check for glitter- none, not even in the filter pleats. Put in new oil, filled the filter, and cranked her up... ZERO oil pressure! Ran it plenty long, and the lifters were getting very noisy, so I knew I had an issue. Long story short, when the oil pump cover kissed the subframe when the motor mount broke, it slightly dented the machined cylinder in the cover casting where the relief valve piston rides. My WOT blast had made the relief valve travel it’s full length for the first time since the motor mount broke, and the relief valve piston hung in the open position because of the pinched spot in the bore. Since the pump and oiling system were full, I just had low pressure... but as soon as I changed the oil it allowed air into the pickup tube and pump, and with the relief valve open and effectively connecting the inlet to the outlet AND being filled with air instead of oil, it couldn’t draw oil up the pickup tube and to the pump at all. Pulled an oil pump cover out of my parts pile, cleaned it and checked the piston travel, installed it, and all was well. That was 25+ years ago and that engine is still running well today.

[Joesworldttv]

I am having the exact same identical issue with my GMC Sierra 1999 SLE truck. I am glad I found this video. Thank you!

[unclesquirrel]

I'm more worried about the gas gauge level LOL

[joeestes]

Awesome video!, iam having the same exact problem and I watched several videos on here and said no way! My engine has a low oil pressure problem because it was rattling (valve training noise) at 5 or 10 lbs pressure! Thanks for sharing this with everyone!

[miniriderh]

Had the very same thing happen to my 2005 Yukon XL Denali. 182K miles all of a sudden the lifters started ticking on startup and after it was warm it wouldn't hold over 20 PSI on HOT idle where it used to be 40+ HOT idle. Going down highway it was about 50 PSI (not far off from normal) so I knew it wasn't the bearings. I bought a Melling High volume oil pump and new pickup tube, Installed in the garage over a 3 day weekend and BAM 50 PSI hot Idle no lifter tick 80 PSI at 6000 RPM. Melling recommend the high volume since it was a little higher mileage engine, and the high pressure spring was only really good for 7 psi up in the rev range, It didn't change much at idle and they said 80 PSI was still safe. Upon inspection I found the original oil pump pickup O-ring was in good condition, It was the Oil Pump Regulator Spring and Piston that was weak and bleeding off pressure. Have 196K miles on it now and runs great. Don't plan to spend 60K+ dollars on a new Yukon so ill be running this one for a while.

[vrswp]

Customer brought in a high-miles truck (LM7) with low oil pressure, but not all the time. He diagnosed it himself LOL and wanted the sender replaced. Still low pressure. (key statement>) Customer claimed he changed the oil himself every 2-3K and wouldn't pay for another oil change so we skipped that step. Came back a couple weeks later with the same complaint, only worse. I dropped the pan to change the o-ring and found the pan was full of sludge and the pickup was stopped up. Looked like it was full of bearing grease - turned out Mr Frequent Oil Change guy was full of shit. I cleaned out the pickup, changed the o-ring and sent shithead on his way with 50-60psi oil pressure.

[Kevin_]

I have a new to me '02 suburban with LM7. 203k on the meter and no issues so far. Its my first LS so I'm watching all the youtubes to learn all I can about preventative maintenance. Dropping the pan on a 4x4 looks like a lot of extra work.

[zackmattox]

An issue I’ve been needing to deal with for a bit, now I have more of an idea of what to check. Thanks Richard!

[andyharman]

This video is really relevant for me. My 2002 Camaro LS1 has had low oil pressure for maybe eight years. I did track days with it steadily since new, and noticed after about 10 years that it was only running about 30 psi when fully hot on track at high rpm. I have not been overly concerned about it, though, because I cut open the used oil filters and never see any bearing debris. And I have oil analyses done that never show high amounts of Aluminum or Iron. I have been assuming that it is a bad reading on the gauge, and have taken the fatalistic attitude that if that amount of oil pressure is not enough, the engine will quit running. I've been wanting to put an LS3 in it for years, but the LS1 just won't die. At 277000 miles, it's earned a rest.

[ericjernagin]

Richard I’m a fan and love your content very informative
I am a gen 12&3 ls fan 90% of the low oil pressure problems I deal with has been that oring You would be surprised at the number of asc certified trained mechanics that just don’t know and would sell the customer an oil pump that’s not needed and accidentally fix the problem with a new oil pump but only because they installed the new oring while installing the new pump ultimately fixing the issue but blaming the wrong part
My 02 surburban 386k original miles nothing but oil changes and regular maintenance op around 20 psi dropped the pan replaced green oring at operating temp 50 -70 psi
Thanks for information though I’m going to share this cuz nobody believes without seeing

[tomasw]

An O-ring. I've looked far and wide and NEVER heard of this. Thanks! And thanks to the others with the screen under the sending unit comments.

[mockingbirdanalog]

My 02 with 320, 000 started having tons of lifter noise. Not even 15-40 would quiet things down. Finally used a quart of engine flush before changing oil and it cleaned out some gunk. I also topped things off with MMO. I used this truck to pull trailers when I built houses. Later I delivered mail in the country with it. It's just a matter of time before I spin a bearing, but it's still running decent. Engine Restore helped too (not sure how adding lead and copper to oil increases compression and power, but it did). Anyway, I'll replace the o-ring. Will give me a chance to look around. Thanks for the practical video!

[michaelangelo]

The information could come in handy for us LS owners.

[mildtowildrc]

Man I got a low oil pressure out of my 5.3 after about 231, 000miles of service❤️👍Maintenance is the key to life and the oil is the blood running thru to keep it alive👍Keep it changed and try Motorkote additive for crankcase and pumps.I use every four oil changes adding 2 ounces per quart of oil.Got 238k on my H2’s 6.0 and runs like new and looks almost new at 15yrs old❤️

[stevepoythress]

Grat topic Richard; stuck oil pump bypass, tons of these back in the day.

[themrjones]

I have the Melling, ever since my oil pump failed because a burr got in the pressure relief valve. Fun job