Might be my worst nightmare.... low oil pressure, tick noise after 75+mph

^^ to add, they're for getting air out of the cooling system and maintaining it's self-bleeding behavior. Hence why the things are so tiny - they don't need to be large to pass some bubbles.

Gentlemen. I have a new to me 2005 5.3l Yukon SLT. 236k At purchase I had a tick at start and went away as it warmed. Had oil and filter changed within that first hour. After 200 original miles, tick came back and stayed longer. Then stayed all day. Stopped driving. Researched everywhere. Solution. Used Motor Medic Motor Flush. (cold engine. run 5 mins max at idle.) changed oil and filter. New oil Valvoline blended high mileage oil and wix filter. added 1/3 qt. Rislone. Oil drained was dirty and had some blobs in it. (Pre- purchase inspector scoped engine and found nothing in the top end.) Have not heard tick or anything from engine in 400 miles. I had a low oil pressure of 20 lbs. now back to 39 lbs. Not as high as when purchased, pressure was almost 50 lbs. I am happy. Plan to flush once more in 1-2k just to be sure. The oil galleries seem to be affected by sludge. Lots of ticking and stuck lifters. Post 2005 are horrid and need to be either manually released and cleaned with Chem-12 or socked with it to keep the sticktion from causing the ticking. PS there is a screen under the oil pressure sender. replace after cleaning the engine. It is like $4. It affects the sender.

Sockeyedsushi said:

Gentlemen. I have a new to me 2005 5.3l Yukon SLT. 236k At purchase I had a tick at start and went away as it warmed. Had oil and filter changed within that first hour. After 200 original miles, tick came back and stayed longer. Then stayed all day. Stopped driving. Researched everywhere. Solution. Used Motor Medic Motor Flush. (cold engine. run 5 mins max at idle.) changed oil and filter. New oil Valvoline blended high mileage oil and wix filter. added 1/3 qt. Rislone. Oil drained was dirty and had some blobs in it. (Pre- purchase inspector scoped engine and found nothing in the top end.) Have not heard tick or anything from engine in 400 miles. I had a low oil pressure of 20 lbs. now back to 39 lbs. Not as high as when purchased, pressure was almost 50 lbs. I am happy. Plan to flush once more in 1-2k just to be sure. The oil galleries seem to be affected by sludge. Lots of ticking and stuck lifters. Post 2005 are horrid and need to be either manually released and cleaned with Chem-12 or socked with it to keep the sticktion from causing the ticking. PS there is a screen under the oil pressure sender. replace after cleaning the engine. It is like $4. It affects the sender.

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Thank you! I changed the oil sending unit, and underneath it, there was no filter. I'm guessing it was missing. I will buy it and place it, I will change the coolant crossover lines because I think they are the wrong ones. Plus they need the gasket changed, tiny leak. Also will change the knock sensors, keep getting a code on it.

I'll do this motor flush before I do the oil pick up tube ring replacement, or should I do that first?

I am a little worried the flush will loosen up gaskets leaks if any
But I rather have a leak I can change than no oil pressure.

Thanks again for the valuable input.

Sent from my SM-N960U using Tapatalk

DenaliReyes said:

Thank you.

The oil pressure stays steady at 20 after it warms up. But I would have to drive it for that because if I just turn it on, it goes up to 30nthen down to 5 and the alarm goes on.

I have to steady rev it to keep the pressure above 20.
After a while like 10 mins of driving it stays at the low 20sh.

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20 is low, I've got 150K on my 06 Yukon XL , using 10W-30 Castrol Synthetic and my pressures are always 50 to 55 even in 100* weather, even at idle.

First post here. Be patient.

I had a similar problem recently.
Bought a 06 5.3 Vortec. (My second Tahoe, love them)
Oil pressure would hover around 10 at idle, (40 at best after warm and acceleration.)
Would drop dangerously lower than 10 sometimes.

Tick would come from the same area you mentioned randomly, but not until at least 15 minutes driving.

One mechanic checked it out, couldn't duplicate, changed oil and sent me on my way.

Few days later, at 70mph, heard the ticking at really fast, short frequency.

Immediately took it to another mechanic for second opinion.

He wanted to change pump, but in the middle of the job saw that the pickup tube o ring was cracked. Changed that instead.

Truck runs perfect. 40psi to 65 psi.
Ticking gone.

Not sure about the coolant issue, but your oil pressure/ticking sounds very familiar.

It was at 198,000 miles when this occurred.

Ozlander said:

20 is low, I've got 150K on my 06 Yukon XL , using 10W-30 Castrol Synthetic and my pressures are always 50 to 55 even in 100* weather, even at idle.

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Thank you, I'm sure this is what I will end up doing, currently looking up YouTube videos on how to do it myself. Recently laid off so trying to penny punch as much as I can. This def helps me, thank you.

The coolant issue so far it doesn't really affect the drive.




Today I'm adding 10x30 Mobil 1 with some lucas additive and see If that helps out.

CliffGray said:

First post here. Be patient.

I had a similar problem recently.
Bought a 06 5.3 Vortec. (My second Tahoe, love them)
Oil pressure would hover around 10 at idle, (40 at best after warm and acceleration.)
Would drop dangerously lower than 10 sometimes.

Tick would come from the same area you mentioned randomly, but not until at least 15 minutes driving.

One mechanic checked it out, couldn't duplicate, changed oil and sent me on my way.

Few days later, at 70mpg, heard the ticking at really fast, short frequency.

Immediately took it to another mechanic for second opinion.

He wanted to change pump, but in the middle of the job saw that the pickup tube o ring was cracked. Changed that instead.

Truck runs perfect. 40psi to 65 psi.
Ticking gone.

Not sure about the coolant issue, but your oil pressure/ticking sounds very familiar.

It was at 198,000 miles when this occurred.

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I'd bet on pick-up o ring..on my 06 Denali w/ 195k had a bad tick on start up low/no pressure and would got away after 10 seconds or so (till the pick-up had oil back in it) was lucky enough to have access to shop with a lift dropped the front axle some and then the pan changed the $10 o ring out it back together changed filter filled with oil let it warm up good to look for leaks too it out and almost pegged the gauge and I never seen it over 45 since I bought with 133k.. not a tick since.

Breeze - Nice!
Wish I had the means to try it myself.
I was charged 800 dollars for that 10 dollar part swap out. (A shop here that's notorious for being expensive, but always solid work)
To be honest though, I was happy to give it to them.
Like DenaliReyes, I was fearing the worst!!

Breeze said:

I'd bet on pick-up o ring..on my 06 Denali w/ 195k had a bad tick on start up low/no pressure and would got away after 10 seconds or so (till the pick-up had oil back in it) was lucky enough to have access to shop with a lift dropped the front axle some and then the pan changed the $10 o ring out it back together changed filter filled with oil let it warm up good to look for leaks too it out and almost pegged the gauge and I never seen it over 45 since I bought with 133k.. not a tick since.

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I have previously posted about oil pressure issues with my '06 Denali. That truck also came from Texas with a coolant system full of water. I caught the water issue before winter. I live in Minnesota. I have seen the damage of coolant freezing, it destroys engines.

I went through all the steps to repair it, sending unit, gauge repair, o-ring, oil pump, and nothing worked. Finally got the oil tested and they found high levels of what would be bearing material. I definitely recommend the oil test. It would have saved me a bunch of time. I used Blackstone labs.

Don't try to put a screen under the oil sending unit. Your engine should not have one. They were not used until 2007 in the Yukons and Suburbans. They are not sending unit filters. they are used to filter oil to the lifters. They were used when the went to the DOD (Displacement on Demand) engines. Unless you have had an engine swap there is no screen there.

You mentioned something about the oil pressure starting around zero, then going to 20 PSI after it warmed up a bit. That may be significant. Search the other posts on low oil pressure on this site. That can sometimes mean sludge blockage in the pan or in the oil pump pressure relief. I can't remember the possibilities, but they are somewhere on this site in other posts. Most pressure starts a bit higher then drops as the oil warms and thins a bit.

I have been running with this problem for probably a year now. I just run Mobil 1 0W-40W and STP oil treatment to thicken the oil a bit more. My problem is slowly getting worse but thicker oil helps for awhile. Tough on the engine during the cold winters but the engine is getting pulled soon anyway. Good luck.