Tahoe 2011, low oil pressure - After engine lifter and cam rebuild

[THESNIPER]

Hi Gentlemen,
This is my first post

I know low oil pressure threads are alot, i read so many, but my issue is a bit different and needed your experience. This why i

So i got a 2011 tahoe 5.3 running 160k miles using Motorcraft 5w-30 fully synthetic (a goot option where i live) chaning it every 5k miles.
- had low pressure at around 20 when worm and idle. Replaced the oil pan o-ring no avail, moved on and changed the oil pump with high volume type. Pressure was so much improved.Got 30-35 on idle and worm. 40-42 idle and cold. No issues no ticking sound, nothing. Was very happy with it drove it for a couple of months it was great.

- Ran 5k more miles on the new pump, then one morning, heading to work, engine had bad lifters sound, getting worse every mile. Immediatley took it to a shop.
They advise to change the lifters and cam and oil pan o-ring, since oil pressure was ok and the pump was new, mechanic didnt change it. Cost me alot hoping this will be the end of it.

Engine after cam/lifters replacement was running good. Recieved it from the shop without issues.

Week by week, now after two months since the lifters replacemebt, low oil pressure is back at it getting worse abd worse.

When cold its at 40, with higher RPMs 1500-2000 when cold it reaches 50. (Looking great)

But what is killing is when it gets worm after a long drive, it drops to to 19-20 at idle with same oil visocsity 5-W30.

What is hurting my brain is that the pump output changed at idle and worm, from 30-35 before the re-build, to 19-20 after it, and with running only for 5k miles.

Tried getting the car on a slope to check the o-ring, no change. Oil reading are a bit realistic so im not suspecting the sensor or its screen. Changed oil again with new filter full synth no improvement at all.

Appreciate your support gents


Thanks in advance







-

 

[donjetman]

20 psi is not low at warm idle. It's good.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

Confirming above, my oil pressure is around 20 psi when warm and idling. That is normal.

 

[iamdub]

Hi Gentlemen,
This is my first post

I know low oil pressure threads are alot, i read so many, but my issue is a bit different and needed your experience. This why i

So i got a 2011 tahoe 5.3 running 160k miles using Motorcraft 5w-30 fully synthetic (a goot option where i live) chaning it every 5k miles.
- had low pressure at around 20 when worm and idle. Replaced the oil pan o-ring no avail, moved on and changed the oil pump with high volume type. Pressure was so much improved.Got 30-35 on idle and worm. 40-42 idle and cold. No issues no ticking sound, nothing. Was very happy with it drove it for a couple of months it was great.

- Ran 5k more miles on the new pump, then one morning, heading to work, engine had bad lifters sound, getting worse every mile. Immediatley took it to a shop.
They advise to change the lifters and cam and oil pan o-ring, since oil pressure was ok and the pump was new, mechanic didnt change it. Cost me alot hoping this will be the end of it.

Engine after cam/lifters replacement was running good. Recieved it from the shop without issues.

Week by week, now after two months since the lifters replacemebt, low oil pressure is back at it getting worse abd worse.

When cold its at 40, with higher RPMs 1500-2000 when cold it reaches 50. (Looking great)

But what is killing is when it gets worm after a long drive, it drops to to 19-20 at idle with same oil visocsity 5-W30.

What is hurting my brain is that the pump output changed at idle and worm, from 30-35 before the re-build, to 19-20 after it, and with running only for 5k miles.

Tried getting the car on a slope to check the o-ring, no change. Oil reading are a bit realistic so im not suspecting the sensor or its screen. Changed oil again with new filter full synth no improvement at all.

Appreciate your support gents


Thanks in advance







-

Send an oil sample to Blackstone.

Your pressure numbers seem fine and fairly typical for these things.

What's getting me is the reduction in the pressures you averaged after the HV pump. Did the mechanic shop bother to inspect the cam bearings? Are the new cam and lifters stock replacement pieces or did they delete AFM?

Did they replace the VLOM and/or its gasket? I'm looking at the ray of hope that you just have a leaky VLOM gasket, if not just loose VLOM bolts.

 

[THESNIPER]

Send an oil sample to Blackstone.

Your pressure numbers seem fine and fairly typical for these things.

What's getting me is the reduction in the pressures you averaged after the HV pump. Did the mechanic shop bother to inspect the cam bearings? Are the new cam and lifters stock replacement pieces or did they delete AFM?

Did they replace the VLOM and/or its gasket? I'm looking at the ray of hope that you just have a leaky VLOM gasket, if not just loose VLOM bolts.

New cam and lifters are stock, AFM is not deleted. I believe the solenoids are not replaced.

As u said the reduction is in pressure what really concerns me as i believe im hearung slight ticking noise when idle (no dashboard warnings yet). Ive even suspected the mechanic replaced it with something else, but the cold startups are still same before the rebuild. Only thing is the massive difference of reduction when worm.

Unfortunately where i live there is no labs doing oil analysis.

Im thinking to go with higher oil viscosity but im not sure which, would that hurt the new cams/lifters as their tolerances will still not worn out.

 

[swathdiver]

So i got a 2011 tahoe 5.3 running 160k miles using Motorcraft 5w-30 fully synthetic (a goot option where i live) chaning it every 5k miles.
- had low pressure at around 20 when worm and idle. Replaced the oil pan o-ring no avail, moved on and changed the oil pump with high volume type. Pressure was so much improved.Got 30-35 on idle and worm. 40-42 idle and cold. No issues no ticking sound, nothing. Was very happy with it drove it for a couple of months it was great.

Let me confirm two things. First, which 5.3 do you have, the iron block LMG or the aluminum LC9?

Second, what is the brand and part number of the oil pump that was put in?

 

[iamdub]

New cam and lifters are stock, AFM is not deleted. I believe the solenoids are not replaced.

As u said the reduction is in pressure what really concerns me as i believe im hearung slight ticking noise when idle (no dashboard warnings yet). Ive even suspected the mechanic replaced it with something else, but the cold startups are still same before the rebuild. Only thing is the massive difference of reduction when worm.

Unfortunately where i live there is no labs doing oil analysis.

Im thinking to go with higher oil viscosity but im not sure which, would that hurt the new cams/lifters as their tolerances will still not worn out.

Synthetic oil maintains its viscosity much better than conventional, so it shouldn't be that much of a difference from the oil. Such a change could be a seal softening when warm. The easiest is to check the VLOM. Even the bolts are known to get loose with age from the gasket collapsing. How comfortable are you with popping off the intake manifold?

You mail the sample to Blackstone. Create an account at their site and request a sample kit. It's free and includes a return shipping pouch and pre-paid shipping label.

Higher viscosity oil would raise the pressure but it wouldn't fix whatever might be failing to cause the drop. It might help for a little while to give you temporary peace of mind. But, if you do have a problem, it'll eventually get worse.

And, yeah, what James said. We gotta know what we're working on here.

 

[THESNIPER]

Let me confirm two things. First, which 5.3 do you have, the iron block LMG or the aluminum LC9?

Second, what is the brand and part number of the oil pump that was put in?

Im sorry im not that of an expert. How can i identify which block type i am having.

For the pump part #12612289

 

[THESNIPER]

Synthetic oil maintains its viscosity much better than conventional, so it shouldn't be that much of a difference from the oil. Such a change could be a seal softening when warm. The easiest is to check the VLOM. Even the bolts are known to get loose with age from the gasket collapsing. How comfortable are you with popping off the intake manifold?

You mail the sample to Blackstone. Create an account at their site and request a sample kit. It's free and includes a return shipping pouch and pre-paid shipping label.

Higher viscosity oil would raise the pressure but it wouldn't fix whatever might be failing to cause the drop. It might help for a little while to give you temporary peace of mind. But, if you do have a problem, it'll eventually get worse.

And, yeah, what James said. We gotta know what we're working on here.

Ill will be looking for some labs who do oil analysis in my country (mid-east) and do the analysis as soon as i find one. I really do not have the right tools/place to do to some mechanic work, so it will be difficult to remove engine parts on my own.

 

[swathdiver]

Im sorry im not that of an expert. How can i identify which block type i am having.

For the pump part #12612289

The 8th digit of your VIN will be a zero or a three. LMG or LC9. Most Tahoes will have the LMG. If that is the case, you have the wrong oil pump.

12612289 has been superseded by 12710304 which is the Melling M365 and these pumps were made for the aluminum block engines with their increased tolerances. They pump oil at a lower pressure and 1/3 more volume per revolution. The spring pressure is set to bypass at 36 psi or so once warmed up.

The current part number for an LMG or iron block motor is 12710303 which is the Melling M295.

Having said that, I can't say that this is the source of or your only problem, at least not now, just got back from an eleven hour run and am winding down before hitting the rack. There are guys on here who know more about this stuff than me as well. The only other thing I can think of is to make sure that Ford oil is Dexos 1 Gen2 certified.

@Scottydoggs @rockola1971 @91RS @01ssreda4 @randeez