Oil Pressure

[BG1988]

so i filmed a video of acceleration, constant gas, and took a photo at a red light is my oil pressure normal? I just got my oil changed I have 100,000 miles on it its a 2013 5.3 videos wouldn't load but idle was between the 20 and 40 mark around 30-35 and when i get on it it can go past 40. this pic was from the stop light. Also my tahoe has afm/dod turned off.

View attachment 230878

58PSI @ 1600RPM @50mph

idle is 45-50psi

but it does use the High performance corvette oil pump. that is used in the
LT1 engine

GM lied to everyone claiming the Corvette was the first to use them...as seen here

https://media.chevrolet.com/media/u.../news/us/en/2012/Oct/1024_GenVSmallBlock.html

just hit find and type in "It is driven by a new, variable-displacement oil pump that enables more efficient oil delivery, per the engine’s operating conditions"

the LFA engine RPO LS2 based
is the one known to be the first to use it.. gen4

 

[BG1988]

I would suspect a bad o-ring on your oil pick up tube before a bad pressure relief valve. Either is possible, but based on the number of folks posting issues with oil pressure like yours, the majority solve it with a new o-ring on the tube.

there is a way to cheat test that by overfilling the crank case

 

[wjburken]

there is a way to cheat test that by overfilling the crank case

Yes, as Brent mentioned, but didn’t go into any detail about, there is a crude way to try and test whether or not the o-ring is the problem.

Basically you want to try and get the oil level in the pan above the o-ring and see if the oil pressure comes back to normal.

This involves a combination of overfilling the oil pan and putting your truck on a steep incline with the front down hill. If, when the oil level is above the o-ring location, the oil pump should be able to draw a good prime and get the pressure up.

Problem with this is if you do this, and you don’t see an improvement, is it because it is truly something other than an o-ring or just that you didn’t get the oil above the o-ring.

Personally, since either the o-ring or the pressure valve requires the oil pan to be pulled to fix, just pull the oil pan in the first place. If the o-ring looks ok, replace it anyways because it’s cheap and you’re already there. Same goes for the pressure relief valve.

 

[daves07 tahoe]

The most likely cause of a low oil pressure issue in a 5.3 is a blocked oil pressure unit screen or an oil pump o-ring failure. HOWEVER - there is an often overlooked and very common issue that puts many of these engines in the junkyard FOR NO REASON. It is a weak or failing oil pressure relief valve inside of the oil pan. If ALL of the above does not fix the oil pressure issue - it IS the relief valve inside of the oil pan. The spring wears out in these valves, which causes oil to simply dump into the pan - and not feed the upper part of the lifter feed circuit. The oil pressure sending unit is located in this circuit - which is the reason you get a low oil pressure indication - when in fact oil pressure is good. The fix is to either replace this valve, or to simply install a plug so the oil does not dump into the pan.... When you block this off - oil pressure will be better than before....
Also, the tell tale sign of a failing oil pressure relief valve spring is a constantly fluctuating oil pressure indication, and pressure falling to zero after a few minutes - or low enough to set a "stop engine low oil pressure" message. If all of the above does not work, drop the oil pan and replace this valve or just block it off...

My 2007 5.3l Tahoe w/225k has been suffering from fluctuating oil pressure, I replaced the screen and sending unit, no change. The pressure is very low (10psi or less) on startup, it climbs when engine RPMs are above about 1,000, but then quickly drops back at idle, I wonder if this could be the pressure relief valve, in the oil pan, you mention above. I did not know that existed. Could it be that sludge is causing the valve to stick? I am considering dumping a quart of ATF into the motor, running it at idle for 15-20 minutes, then changing oil to see if it removes sludge and frees the valve. A whole lot easier than dropping the pan. Thoughts?

I would suspect a bad o-ring on your oil pick up tube before a bad pressure relief valve. Either is possible, but based on the number of folks posting issues with oil pressure like yours, the majority solve it with a new o-ring on the tube.

Appreciate the response. I have seen several Utube videos that illustrate a way to replace the o-ring (and oil pump) without dropping the pan. I assume you can not inspect, clean or modify the pressure relief valve unless you drop the pan. Correct?

 

[wjburken]

Appreciate the response. I have seen several Utube videos that illustrate a way to replace the o-ring (and oil pump) without dropping the pan. I assume you can not inspect, clean or modify the pressure relief valve unless you drop the pan. Correct?

I have seen videos showing how to replace the o-ring with out dropping the pan as well, but I believe they all started with the timing cover being removed. They also don’t show you having to take the oil pan off anyways in the event you accidentally drop the small bolt that holds the pick-up tube to the oil pump into the oil pan.

When I needed to replace my camshaft, I needed to get that bolt of so I could pull my oil pump. Against my better judgement, I bought into the video short cuts and I spent more time than made sense trying to get it off without dropping the oil pan. Once I decided to just pull the pan I was kicking myself for trying to take a short cut not doing it right in the first place.

If I were doing this I would just bite the bullet and drop the oil pan. You will be time ahead and will be able to see what type of crap is in your oil pan while you’re in there.

 

[daves07 tahoe]

Yes, as Brent mentioned, but didn’t go into any detail about, there is a crude way to try and test whether or not the o-ring is the problem.

Basically you want to try and get the oil level in the pan above the o-ring and see if the oil pressure comes back to normal.

This involves a combination of overfilling the oil pan and putting your truck on a steep incline with the front down hill. If, when the oil level is above the o-ring location, the oil pump should be able to draw a good prime and get the pressure up.

Problem with this is if you do this, and you don’t see an improvement, is it because it is truly something other than an o-ring or just that you didn’t get the oil above the o-ring.

Personally, since either the o-ring or the pressure valve requires the oil pan to be pulled to fix, just pull the oil pan in the first place. If the o-ring looks ok, replace it anyways because it’s cheap and you’re already there. Same goes for the pressure relief valve.

I overfilled the crankcase by adding 1 qt of ATF plus 1/2 qt engine oil, saw an immediate improvement upon starting (averaging about 20 psi) then put it on a downslope at idle for 15 min. The pressure did not dip below 10 psi as it was before. Then I ran it on an upslope and the pressure was fluctuating more significantly with a lower average reading then on the downslope. I believe this indicates a bad o-ring on the pickup tube as the most likely culprit. Agree?

Another interesting outcome was that the motor had developed a clear tap (assume a lifter) and within 10 minutes of overfilling the crankcase with ATF the noise disappeared.

Extremely helpful forum - Thanks

 

[wjburken]

I overfilled the crankcase by adding 1 qt of ATF plus 1/2 qt engine oil, saw an immediate improvement upon starting (averaging about 20 psi) then put it on a downslope at idle for 15 min. The pressure did not dip below 10 psi as it was before. Then I ran it on an upslope and the pressure was fluctuating more significantly with a lower average reading then on the downslope. I believe this indicates a bad o-ring on the pickup tube as the most likely culprit. Agree?

Another interesting outcome was that the motor had developed a clear tap (assume a lifter) and within 10 minutes of overfilling the crankcase with ATF the noise disappeared.

Extremely helpful forum - Thanks

Well, looks like you have your answer to your oil pressure question. Like I said in an earlier post, the o-ring is one of the most common causes of oil pressure issues.

As for the ATF, ATF does have some detergents in it but not much more than good oil has. The thing that ATF has is dispersants that will keep crap and crud in suspension better. Glad to hear you might have also cleared up a noise in your engine.

Now, get busy draining your overfilled oil pan, drop it and get that O-ring replaced!

Happy New Years!

 

[daves07 tahoe]

I have seen videos showing how to replace the o-ring with out dropping the pan as well, but I believe they all started with the timing cover being removed. They also don’t show you having to take the oil pan off anyways in the event you accidentally drop the small bolt that holds the pick-up tube to the oil pump into the oil pan.

When I needed to replace my camshaft, I needed to get that bolt of so I could pull my oil pump. Against my better judgement, I bought into the video short cuts and I spent more time than made sense trying to get it off without dropping the oil pan. Once I decided to just pull the pan I was kicking myself for trying to take a short cut not doing it right in the first place.

If I were doing this I would just bite the bullet and drop the oil pan. You will be time ahead and will be able to see what type of crap is in your oil pan while you’re in there.

roger that!
Thx

 

[daves07 tahoe]

Well, looks like you have your answer to your oil pressure question. Like I said in an earlier post, the o-ring is one of the most common causes of oil pressure issues.

As for the ATF, ATF does have some detergents in it but not much more than good oil has. The thing that ATF has is dispersants that will keep crap and crud in suspension better. Glad to hear you might have also cleared up a noise in your engine.

Now, get busy draining your overfilled oil pan, drop it and get that O-ring replaced!

Happy New Years!

I'm on it!
Thx and Happy New Year

 

[daves07 tahoe]

roger that!
Thx

I dropped the oil pan and the o-ring on the pickup tube was brittle. So hard it broke in two while trying to remove it very gently. Obviously an issue, but should I replace the dump valve above the oil filter while I have it apart? I read that sometimes the spring gets weak.