So on this GMC Yukon I have, my oil pressure is being kind of weird compared to my older trucks that I no longer own. So when I start my truck in the morning, the oil pressure is a hair above 40 psi. I let the truck idle and warm up for about 15 minutes before I head to work. The truck is not fully warmed up when I pull away from my place, but the oil pressure is at 40 psi idle at that time. As I get going the pressure is about 55 on normal acceleration. I get on the freeway for my commute to work, and the oil pressure is about 50 to 55 psi while cruising for the first 5 minutes on the freeway. All the sudden it gradually drops to 45 psi on the freeway but fluctuates up and down 2-3 psi. At idle when I get to work it’s idling at 33 psi. I know it’s almost time to change the oil on this rig. I am wondering is this a tell tale sign the pick up tube o ring is going or is this a clogged oil filter. My old 06 Silverado always had higher pressure and it had low pressure like this one time due to a clogged oil filter. Any input would be appreciated.
Normal oil pressure or am I just over reacting.
- Thread starter mdmcinti
- Start date
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STOP driving not sure how the set up is but under 40 is bad the pick up ring is failing or the sensor or needle on the cluster
i know it’s not the gauge because I replaced all of them like a month ago. It doesn’t have any lifter noises or anything. I had an o ring fail on another 06 I had and it had way lower oil pressure and horrible lifter tick
I would change your oil and put a fresh filter on and see what happens. My guess is your pressure will stabilize.
You might see if you can pull the oil pressure sensor and pull the screen out that is below that and see how plugged it is and make sure it’s clean. Might as well put a new sensor in just because it’s already out.
What brand/type/weight of oil are you using?
How many miles on the vehicle?
Ppp
That’s right. Missed where you said you just replaced it.
the vehicle has over 226k on it. I have no idea on the history of the vehicle, but it is super clean and much better looking than other vehicles I have experienced with high mileage. I am using 5w-30 valvoline max life full synthetic.
swathdiver
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Pressure is normally much lower when the o-ring goes. AFAIK, yours will not have a screen under the oil pressure sensor. That's a GMT900 AFM thing. Have you recently changed brands of oil filters? I found some filters lowered my oil pressure compared with others. Change the oil and filter and observe again, keep an extra couple of quarts on board in case it is the o-ring. Should it go bad, dump in 2 more quarts to submerge it and keep driving until you get it fixed.
It had a crappy Delco e core on it when I bought the truck and I put the same on when I changed the oil. I heard rose e cores can be crappy sometimes and cause this issue. I hope oreilys still sells the good none e core filters still. If not I put a wix filter on it.
I'm just doing my oil pan and pickup o-ring. Also, the mesh screen was about 1/3 clogged. Once I'm done I'll be able to tell you if there is any change in my oil pressure. Currently, mine doesn't drop below 40 psi, BUT when I had my cracked head the coolant slowly mixed with the oil and began to sludge it. Then, it would drop below 40 psi. Even if all I did was change the oil filter, the oil pressure was restored, but I usually did a full oil change. I've since fixed the head and the oil pressure remains above 40 psi.
Now that I'm doing my o-ring, it will be interesting if my oil pressure goes a little higher. The old ring was a little squashed, but still working. Of course, I also had a partially blocked oil screen. I'll know in a day or two. ( I work slowly. Rickafix would probably have this all together in 15 minutes... not me
)
Now that I'm doing my o-ring, it will be interesting if my oil pressure goes a little higher. The old ring was a little squashed, but still working. Of course, I also had a partially blocked oil screen. I'll know in a day or two. ( I work slowly. Rickafix would probably have this all together in 15 minutes... not me
)
swathdiver
Full Access Member
I think those old ones are long gone. The K&N with the nut on the end is better than even WIX, which is a great filter.
I'm just doing my oil pan and pickup o-ring. Also, the mesh screen was about 1/3 clogged. Once I'm done I'll be able to tell you if there is any change in my oil pressure. Currently, mine doesn't drop below 40 psi, BUT when I had my cracked head the coolant slowly mixed with the oil and began to sludge it. Then, it would drop below 40 psi. Even if all I did was change the oil filter, the oil pressure was restored, but I usually did a full oil change. I've since fixed the head and the oil pressure remains above 40 psi.
Now that I'm doing my o-ring, it will be interesting if my oil pressure goes a little higher. The old ring was a little squashed, but still working. Of course, I also had a partially blocked oil screen. I'll know in a day or two. ( I work slowly. Rickafix would probably have this all together in 15 minutes... not me
I have done it on a 2wd Silverado and it was not that bad. No one told me I had to drop the steering rack for the pan to come off. I have never done it on a 4wd truck like my Yukon is. I’m sure lowering the axle isn’t all that bad. Let me know what you find out. As for the coolant thing, I should look at my coolant level. For all I know I have a set of castech heads that were never replaced.
TheAutumnWind
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Bah... the more I look into this the more I realize that I need to address my low hot idle oil pressure. I am seeing in the ~25 psi range. I don't notice any sudden fluctuations or anything, just that it seems low. Ill have to top off the oil to see if it gets any better.
I am thinking I might as well just replace the pump and be done with it rather than drop the pan (and front axle... darn AWD) for an O ring. m295 here we come...
BTW running full synthetic 5w30 with uhh stp s3980xl atm. I have run mobile 1's and fram ultra synthetic filters and various full synthetic oils with the same pressure.
@~200k miles now.
I am thinking I might as well just replace the pump and be done with it rather than drop the pan (and front axle... darn AWD) for an O ring. m295 here we come...
BTW running full synthetic 5w30 with uhh stp s3980xl atm. I have run mobile 1's and fram ultra synthetic filters and various full synthetic oils with the same pressure.
@~200k miles now.
I would think it would be easier to drop the axle than pull the crank pulley. I think pulling the crank pulley we be more difficult and doing it that way would be more time consuming since you have to remove more things like the water pump to get the timing cover off. These pumps are pretty bulletproof. The only thing that would go bad on the pump is the oil pressure relief valve. There is a video about that on YouTube.
HACK BLOCK
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found this under common specs and procedures in my manual
avalonandl
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As long as your over 20 psi your fine. These engines have lower pressure pumps.
TheAutumnWind
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Interesting. Even the LQ9?
Its not that I am concerned that its going to blow up tomorrow, more that @ ~200k miles and 15 years old I figure that I would rather do this before it becomes a real problem.
SnowDrifter
Full Access Member
33@hot idle is fine. You want it north of 30. Disregard the GM specs.
You have the same issue I had. Mine would fluctuate a bit, though mine was also verified with a mechanical gauge. Hook it up on your end to see if it's electrical or mechanical.
What I found on tear down was that the oil pump had some cavitation wear on the pump/rotor as well as scoring where the relief valve started to stick. New oil pump was the fix for my particular issue.
You have the same issue I had. Mine would fluctuate a bit, though mine was also verified with a mechanical gauge. Hook it up on your end to see if it's electrical or mechanical.
What I found on tear down was that the oil pump had some cavitation wear on the pump/rotor as well as scoring where the relief valve started to stick. New oil pump was the fix for my particular issue.
TheAutumnWind
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Yeah I am in the mid to low 20's hot idle.
This sounds like a tell tail sign of a weak oil pressure relief valve spring (not the one in the pump - it is the one in the pan). It is THEE most missed and overlooked problem when it comes to oil pressure issues on these engines. In time your pressure may go down to zero or close to it and the low oil pressure alarm will ding. When/if that happens - it won't be the end of the world, because it is kind of a false reading. A weak pressure relief valve simply will dump more oil into the pan and it won't reach the sensor. You must drop the pan when changing this - so it is prudent to change the pick up tube o-ring while you are at it..
It is #455. Part #12594579.. OR you can simply install a plug and never have to worry about oil pressure again. My Tahoe did all of the above - and I changed everything (pump, pressure sensor and filter screen, pickup tube o-ring) before I studied the oil system and discovered the relief valve in the pan...
It is #455. Part #12594579.. OR you can simply install a plug and never have to worry about oil pressure again. My Tahoe did all of the above - and I changed everything (pump, pressure sensor and filter screen, pickup tube o-ring) before I studied the oil system and discovered the relief valve in the pan...
