5.3 rebuild guestions

[iamdub]

Engine has 158k on it. I am the second owner. Oil changes have been Penzoil Ultimate Platinum and Wix filters. I am getting low oil pressure. Turn the truck off for a few restart and I am good for a little bit and comes back. Have about 20 psi and slowly drops until the alarm comes on. So I was thinking of a rebuild. I want to delete the dod and I need to replace the cats. If the bearings are worn and causing the low oil pressure. I was thinking now would be the time to do the rebuild.
I have rebuild motors before 350, Chrysler 3.8 and 3.3l engines.
If I rebuild what oil pump is recommended? High volume?

158K is NOTHING on these engines. It shouldn't need a rebuild. There are a handful of well-documented causes for low pressure as well as false low pressure readings on the gauge. Unless you're just bored and wanna tear into it, I wouldn't take it apart.

Properly diagnose the cause of the alleged low oil pressure, which begins by first confirming that you do, in fact, have low pressure. I support deleting AFM. If you have sound reason for pulling the engine (such as resealing it to fix oil leaks) and you're already geared and psyched up for it, that would be a great time to delete AFM.

I did this in 2020 when mine hit 200K miles. Pulled it, deleted AFM, made a few upgrades and sent it. Compression and cylinder walls were great and bearings were okay. You're using great oil and filters and I doubt you beat on yours. I'm strongly betting you have a failed O-ring.

 

[swathdiver]

Yes, 2 ton engine hoist is no problem lifting the engine, even boom extending all the way out.

You sure about the 2-Ton being able to do that? I thought we needed to use 3-Tons for the reach? @randeez

 

[strutaeng]

You sure about the 2-Ton being able to do that? I thought we needed to use 3-Tons for the reach? @randeez

Um, I thought my HF hoist was 2 ton, but it looks like it's just a 1 ton. I lent it to my brother but it's the gray version. I'm pretty sure it's the same as this one: https://www.harborfreight.com/1-ton...2ReE-bcKPUp88JFgwb7RR0vPWjJtAD1gaAvkREALw_wcB

The out-most notch says 1/4 ton, so like 500lbs fully extended. I dropped in my 5.3 iron block L59 on my Silverado fully extended, but w/o any accessories. But when I went to pull the engine, I yanked it out fully dressed along with the 4L60e. I don't remember what boom notch it was in, however. That was too unwieldy though. Don't recommend that.

Iron block LS engines w/accessories are around 550 lbs -ish IIRC. Aluminum versions are like 100 lbs lighter? Something like that.

 

[donjetman]

I've picked up many a 500+ Lb iron block big block chevy with trans and TC still attached with my harbor freight engine hoist.

 

[donjetman]

I am considering pulling my 5.3 in my 2009 4x4 tahoe and doing a rebuild.

I am looking for any advise, like what to replace and brands. I would like to delete the DoD. Will a 2 ton cherry picker be big enough to pull the motor and any recommendations on a engine stand?

Thanks in advance for any help.
Erik

Possible o-ring leaking that can cause low oil pressure:
oil pump pickup tube o-ring
oil galley barbell o-rings
VLOM cover to oil towers o-rings

 

[Geotrash]

I'll add my voice to the chorus of those saying that at 158K your engine has AT LEAST another 200K in it. The bottom end is built hell-for-stout, so a DoD delete and a refresh of the heads, plus a Blackbear tune, will do wonders. It will feel like a new truck.

Yours doesn't have VVT, so you can choose either a single bolt cam, or from an even wider array of 3-bolt cams. In general though, I wouldn't go too wild on the cam for daily drivability. I have the Cam Motion Stage 2 Truck Cam in my '12, and they also make a grind specific to the 5.3. It's a beast for performance but idles smooth, making it a great sleeper and the stock torque converter works great with it. If you choose the "low-lift" version, you can also use the stock LS6 valve springs.

LMG 5.3L Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More

The LMG engine is a 5.3L Gen. IV iron-block engine used in GM trucks and SUVs between 2007 and 2014. For marketing purposes, it was also known as the Vortec …

www.onallcylinders.com

 

[Dustin Jackson]

Here is the part number of the best factory cam you can put in there, it's a direct replacement you just need to convert to a 3 bolt cam sprocket.

12583623

 

[houstontaylor]

My 2003 Tahoe didn't even burn any oil until 290,000 miles when it suddely started guzzling oil. I had it replaced with a GM remanufactured one and 340,000 miles now. So cylinder wear may not be your problem.

 

[Marky Dissod]

Here is the part number of the best factory cam you can put in there, it's a direct replacement you just need to convert to a 3 bolt cam sprocket.

12583623

Tough to find for under $200, some places selling for as high as $350.
Wonder how much more cam is possible for $400?

 

[Just Fishing]

if your engine starts making ticking noises when the pressure drops, then it might be something like the oil pump, pickup O-ring, etc.
otherwise, it's probably just the sensor.

also don't overfill.
LS's are very sensitive to it, the oil starts getting bubbles and the oil pressure gage will start waving at you.

I had it bad when I tried to run the high-volume pump, but I also still had the bypass in the pan at that time.
So bad I could see bubbles on the dipstick!

I think others mentioned it, check the O-ring by either temporarily overfilling, or even better would be to park it on a slope so the oil in the pan goes to the front of the engine.

And I get better oil pressure using the AC Delco filters.