Engine tick with low oil pressure

Sharpz · October 19, 2023

If this has been addressed somewhere, I am sorry for reposting. I did as many searches as I could but could not find what I was looking for. I have a 2004 gmc sierra 1500 4x4 w/ 5.3 motor. The Motor has 400k on it, and up until recently has had zero internal problems. What changed was my oil pressure started dropping, and when driving would be up past 40 psi, but when I would come to a stop, it would drop to 20, and then progressively it got a bit worse until it would hardly ever get over 40, and would idle to where the low oil pressure warning would come on the display. If I didnt drive the truck for a few days, it would start up with a tick. This was my daily driver and I couldnt just not use it, but I made efforts to pinpoint thep issue/s. I first swapped out the oil pressure sensor with a new offbrand one, and the readings were not exactly the same, but did seem to be a bit higher. Thinking this might be the problem I purchased a new AC Delco OPS and it was exactly like the original. Thinking the next step was possibly the O ring on the pick up tube, I decided to drop the oil pan, since mine was leaking a bit of oil. When I dropped the pan it was clear that it had never been done. Even though I only ever used full synthetic motor oil, and ac delco filters, changing every 3k, there was some build up in the pan. I remember using marvels mystery oil a few times, but stopped using it long ago. I cleaned the pan so that it was clean, as well as the splash guard. I took the oil pressure tube down, and cleaned it up the best I could without a parts washer. I replaced the o ring with a new one and reinstalled everything. No change on the oil pressure. I did not have a tick at this time, as long as the truck didnt sit for multiple days, and even then it would go away after about 7-10 miles of driving. I purchased a new high flow oil pump, thinking this was the next step, but realized I had to drop the pan again and go back through that process and I just didnt have the proper time, and realized tools for this to happen. I did purchase a new HB removal tool and started tearing into the front side of things, before I realized my torque bar only went to 150 flbs, and needed one that went to 240. I also found out after I needed a install bolt for the HB all of which needed to be ordered. Frustrated I put everything back as I didnt have the time any longer and needed the truck. A few days had gone by, and I was driving for about 1 1/2 miles, the truck sounded good, still oil pressure issues but no tick. Then it just shut off. I never changed the fuel pump since I had the truck and assumed this is what happened. I changed out the fuel pump but the truck would not start. It would crank like it wanted to start, but just not catch all the way. I didnt have a fuel pressure tester but when I pressed the port it would spray pretty good, each time I cycled the key. I couldnt find anything else wrong. No codes for anything new, just the existing 02 sensor and the air filter sensor. Frustrated I cranked the engine and pressed down on the gas petal and it started up, and has fired every single time since without fail, runs drives has plenty of power, but now I have a tick.. This is a fresh oil change and I even added lucas to see if it might help, but still a tick and low oil pressure. So here I am, asking for where to go from here. I still plan on doing the oil pump swap out, as Now I have all the tools I need for that, but something I did notice in the last 4 oil changes I have done, all with in a month and less then 1k miles, was a little bit of fine metal on the oil plug. Nothing crazy, but its there.

My questions to all of you are other then the oil pump, new Red o rings, and not black o rings. What can I do while I have this this apart, the oil pan will be down. The oil pump will be open. I have heard a new timing chain probably is a good idea, but really isnt needed.

I do have a 5.3 with 200k miles on it from a new style 99 1500. It always ran good. I planned on putting this in something the same year, 99-02 but if it would work in my 04 I would be open to that.

Grumpy Bear · October 19, 2023

400K! Good for you!

She's tired and bearing clearances have opened up to the point the pump can no longer supply her needs. Be my best guess. The high-volume pump will help. If fact it was made for this situation. But in the meantime, if it were mine, it would get a belly full of 20W50. That will slow the leakage rate. Save that worn bearing from complete failure. Buy you some time. If you keep going as is, a bearing failure is in your future. If this helps, then you have conformation. If it doesn't it could be build up in the oil feed galleys. Lifter tick on high milers can be feed related or it can be worn lifter bores or leaky lifters. As yours is tied to the oil pressure them the 20W50 will let you know in short order what's what.

On that fail to start; likely got flooded when you primed it. Cleared when you cranked it matted. As it should.

Sharpz · October 19, 2023

I will definitely try that 20w 50 after I change this pump. .Thank you for the input. Its been such a reliable truck that I hate not to try everything I can to keep it going. I havent drove it since the tick happened, just meshed the gas pedal while in gear to see if it lost any power, it happily spun the tires. Thanks again.

Grumpy Bear · October 19, 2023

2 hours ago, Sharpz said:

I will definitely try that 20w 50 after I change this pump. .Thank you for the input. Its been such a reliable truck that I hate not to try everything I can to keep it going. I havent drove it since the tick happened, just meshed the gas pedal while in gear to see if it lost any power, it happily spun the tires. Thanks again.

I guess I wasn't clear. 20W50 is something for now, before the high volume pump to slow bearing leakage. You welcome.

Sharpz · October 20, 2023

yeah that does make more sense lol. Just curious as I have seen mixed things on this, but is it possible or even worth it to try and replace the rod bearings while I have the pan down? Obviously I know having this engine completely out and rebuilt would be the way to go, I just cant do it right now. If it is something that isnt a horrible project and the margin of error isnt great, the price is right for the parts.

Grumpy Bear · October 20, 2023

4 hours ago, Sharpz said:

yeah that does make more sense lol. Just curious as I have seen mixed things on this, but is it possible or even worth it to try and replace the rod bearings while I have the pan down? Obviously I know having this engine completely out and rebuilt would be the way to go, I just cant do it right now. If it is something that isnt a horrible project and the margin of error isnt great, the price is right for the parts.

I've actually seen my father do this in the 60's so I know it can be done BUT I've never been comfortable with the idea. He field built Jeep motors during the Korean Conflict. More times than not it isn't the rods anyway. Cam bearings usually go first in high milers. Just say'n......Maybe it will work? :dunno:

I've known what it is to be tapped for cash and tight on time, so I feel ya. But I think the pump and maybe even in combination with the heavier oil IF the pump alone doesn't get it done. Past that every mile is barrowed.

On 10/19/2023 at 5:37 AM, Sharpz said:

the last 4 oil changes I have done, all with in a month and less then 1k miles, was a little bit of fine metal on the oil plug. Nothing crazy, but its there.

Gritty with sparkle or soft and paste like goo?

Sharpz · October 20, 2023

more like soft and paste like. I couldnt see slivers or anything like that. I would describe it as fine filings that were saturated. I could rub it between my fingers and couldnt feel anything like sharp splinters. Also I stuck a power ful magnet in the oil I took out and in the pan itself but nothing came out on that magnet, only on the oil plug magnet and it was only on the tip of it.

update. I drained the oil and added 20w50. No change in pressure or tick. I only added 5 qts and didnt change the filter. When I get vacation I will go ahead and swap out that pump and see if anything changes. Thanks for all the advice.

Edited October 20, 2023 by Sharpz

Jworks · December 5, 2023

I ran 20w50 in a '94 4.3 engine for years. Previously used 10w40 and stp in every oil change till it started using a quart between changes. Then changed to 20w50 Castrol and stp. I finally sold it after 19 yeas with 484k miles on it. Yes, believe it or not someone bought it.

Sharpz · December 28, 2023

Just an update. I have finally got around to swapping out my oil pump. I am waiting 24 hrs for the RTV to set up on the corners of the oil pan, before adding oil, but I am 99.9 percent sure that the o'Ring I installed the first time was not seated properly. I did use the black O'ring that the parts store gave me, but I dont think it was in right. I could see most of the ring just starting to go into the oil pump, and when I installed the new pump and ring, It took like 20 minutes to get it seated. Eventually I had to take the two nuts completely loose on the pick up tube to work the ring in where it was inside the pump dead headed. I then was able thread the bolt almost home then put the nuts on. I have to do this on my tahoe and sure now what needs to be done. Bottom line, I couldnt find anything wrong with the old pump, but since I had the high flow one, I decided to put it in anyway. Hopefully no internal damage was done and I can run here another 100 miles.

Bleepster · December 29, 2023

thanks for the update - keep them coming please - this is an interesting thread.

Sharpz · December 30, 2023

Turns out that the amount of miles I have on this motor, and the low pressure was more then it could take. I do have oil pressure when driving now, around 45 psi at 3800-4000 rpm, not great by any means, but at idle it is only around 15 psi, enough to get a low oil pressure warning. The knock is still present so looks like I will be rebuilding this one. Thank you everyone who contributed to this and past threads.

Bleepster · January 2, 2024

it would be cool for you to make a thread on the rebuild

Sharpz · October 4, 2025

So at the advice of GrumpyBear I used a thicker oil. I opted to use 20w 50 mobile one full synthetic and because I didnt have the time to do a full on rebuild or swap, I figured I would drive this truck for as long as I could. The thing is the knock went away with time, I do have a tick, but nothing like I experienced before and the tick isnt all the time, the truck runs great, plenty of power and I have turned over 465k and still going. I am not saying its right or a solution by any means, just saying I think when this issue first started I was at 400k. Thank you to all who had suggestions.

Edited October 4, 2025 by Sharpz