Low oil pressure....sometimes

[DougAMiller]

Good job! With how common this issue is, this post should be a sticky. You feel content with closure? I do! lol

I think this is close enough to answer why my o-ring test didn't work.

 

[afpj]

I thought that when the manufacturer says oil pan capacity is 6 quarts, that would mean that 6 quarts fills to the top of the oil pan? I was looking at replacing my oil pan and several makers list the oil capacity for the oil pan replacement as 6 quarts,which I assume is the capacity of the Oem pan. Just throwing it out there as this is interesting stuff. Even so, it would not change dougamiller’s estimate too far off.

 

[Rocket Man]

Squirrel!

 

[DougAMiller]

I thought that when the manufacturer says oil pan capacity is 6 quarts, that would mean that 6 quarts fills to the top of the oil pan? I was looking at replacing my oil pan and several makers list the oil capacity for the oil pan replacement as 6 quarts,which I assume is the capacity of the Oem pan. Just throwing it out there as this is interesting stuff. Even so, it would not change dougamiller’s estimate too far off.

Using the dimensions that I found and assuming the casting is about 1/4 inch thick, 6 quarts would fill it to approximately the line that I marked. The pan would hold significantly more filled all the way to the top, by my estimate probably over 12 quarts. The rotating assembly (crankshaft and rods) reach below the block and into the oil pan. If the oil filled it all the way to the top they would whip it into foam, something you don't want happening. So the oil level is certainly below the top of the pan.

When they describe it as a "6 quart" oil pan, they are referring to the depth of the sump. Depending on the vehicle it is intended for, some oil pans for the LS-series engines hold more or less.

 

[afpj]

Thanks for that explanation. Squirrel hunter.

 

[lowpost99]

Hey guys anyone have the o-ring part#? I recall when I did mine a few years back, there was some debate over a red vs. green o-ring with different part#'s.

 

[iamdub]

Hey guys anyone have the o-ring part#? I recall when I did mine a few years back, there was some debate over a red vs. green o-ring with different part#'s.

The size of O-ring depends on the oil pump end style of the pick up tube. You might can find your answer here: https://www.chevyhardcore.com/news/identifying-the-correct-oil-pick-up-tube-o-ring-for-your-ls-swap/

 

[Yuey87]

OK, took it to a shop today to get their assessment. Even though the overfill test didn't kick the pressure back up, I am still thinking o-ring just based on the symptoms. Anyway, they say everything is fine, that it is above the minimum spec, which they state is 6 psi at 1000 rpm. That didn't sound right to me, so I looked it up. Yep, GM specs on the Vortex 5.3's are minimum oil pressure is 6 psi @ 1000, 18 psi @ 2000, and 24 psi @ 4000. So, I'm certainly above the minimums. The only time it gets close is after a cold start, right after it goes from high idle to low idle, but before the oil warms up, it will sometimes get down around 7-10 psi.

I guess as far as risking engine damage, I have sufficient pressure, it's just that it was only 2-3 months ago I don't think I ever saw it under 30 psi. Still feeling like the o-ring should be changed.

The thing about it is yes that's assuming all flow is not impaired in any way if there is any kind of buildup or restriction on flow then that pressure is not going to push that oil. Regardless of minimal spec pressure is overrated ideally you would want decent pressure and good to great oil flow. It's about balance but in this case flow is more important if you have low pressure and Ticking persist at full operating Temps and this was not doing it before oil pressure drop then you clearly have a lubrication issue. Some of these things just tick some people mistake injector noise for lifter noise there are many possibilities play it safe and put a mechanical gauge on it as mentioned before I have a 2003 mine jumps around mostly at higher RPMs after I've driven it for 30 minutes but never drops below 40 at 2500 RPMs 550 rpms its 31 psi plus, and that's in the cluster and through the PCM . I've done everything but cam retainer plate which could be a possibility and oil pump check to see if any manifold bolts have broken off you can gaze this through the fender Wells.

 

[Yuey87]

OK, took it to a shop today to get their assessment. Even though the overfill test didn't kick the pressure back up, I am still thinking o-ring just based on the symptoms. Anyway, they say everything is fine, that it is above the minimum spec, which they state is 6 psi at 1000 rpm. That didn't sound right to me, so I looked it up. Yep, GM specs on the Vortex 5.3's are minimum oil pressure is 6 psi @ 1000, 18 psi @ 2000, and 24 psi @ 4000. So, I'm certainly above the minimums. The only time it gets close is after a cold start, right after it goes from high idle to low idle, but before the oil warms up, it will sometimes get down around 7-10 psi.

I guess as far as risking engine damage, I have sufficient pressure, it's just that it was only 2-3 months ago I don't think I ever saw it under 30 psi. Still feeling like the o-ring should be changed.

 

[Yuey87]

OK, took it to a shop today to get their assessment. Even though the overfill test didn't kick the pressure back up, I am still thinking o-ring just based on the symptoms. Anyway, they say everything is fine, that it is above the minimum spec, which they state is 6 psi at 1000 rpm. That didn't sound right to me, so I looked it up. Yep, GM specs on the Vortex 5.3's are minimum oil pressure is 6 psi @ 1000, 18 psi @ 2000, and 24 psi @ 4000. So, I'm certainly above the minimums. The only time it gets close is after a cold start, right after it goes from high idle to low idle, but before the oil warms up, it will sometimes get down around 7-10 psi.

I guess as far as risking engine damage, I have sufficient pressure, it's just that it was only 2-3 months ago I don't think I ever saw it under 30 psi. Still feeling like the o-ring should be changed.

Based on careful consideration of all of the symptoms and what I have already ruled out, I'm pretty well convinced this is the o-ring. Shouldn't be any sludge, it's been fed nothing but MobilOne synthetic since new, and frequently. The shop that I had look at it didn't want to say anything was wrong since they never saw it go below spec, but I'm going to have them replace it next week. I had to get it back from them because I'm moving my daughter into her dorm this weekend and need it.

The thing about it is yes that's assuming all flow is not impaired in any way if there is any kind of buildup or restriction on flow then that pressure is not goingto push that oil. Regardless of minimal spec pressure is overrated ideally you would want decent pressure and good to great oil flow. It's about balance but in this case flow is more important if you have low pressure and Ticking persist at full operating Temps and this was not doing it before oil pressure drop then you clearly have a lubrication issue. Some of these things just tick some people mistake injector noise for lifter noise there are many possibilities play it safe and put a mechanical gauge on it as mentioned before I have a 2003 mine jumps around mostly at higher RPMs after I've driven it for 30 minutes but never drops below 40 at 2500 RPMs 550 rpms its 31 psi plus, and that's in the cluster and through thePCM . I've done everything but cam retainer plate which could be a possibility and oil pump check to see if any manifold bolts have broken off you can gaze this through the fender Wells.