ElQueFør

Well after running my recently finished turbo build around for a while I have identified what I think to be a problem with the oil pump O ring. Starts up with decent oil pressure although lower than what I read is normal. Somewhere in the 20-25 PSI range cold idle usually. 35+ PSI on acceleration when warm or cold. I've had the pan AND both heads off before dropping it in, and the cylinder bores still had crosshatch pattern from the factory honing process. Also, the inside of the engine was clean enough to eat off of. So, I don't think the engine is worn out, I think I screwed up when I put the O ring in it when it was on the engine stand. Also..... I can't remember 100% but I seem to recall putting a blue oil pump O ring on, the earlier design, and this engine is from a 2003 pickup....... So, I think I used the wrong oil pump O ring to begin with.......

Here's the things I've identified that leads me to suspect the O ring on the oil pump:

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After warming up, the idle PSI sometimes drops as low as 15 PSI.

The lifters make a ticking sound that ONLY happens after heat soaking the engine and spinning it fairly high. ~4K RPM.....

Finally, The dipstick ALWAYS has bubbles on it when checking it HOT.

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I've found many threads which further make me suspect the O ring. Here are just a few of them that I've found.



https://ls1tech.com/forums/generatio...blem-help.html

https://ls1tech.com/forums/generatio...-symptoms.html

https://ls1tech.com/forums/general-m...p-reached.html

https://ls1tech.com/forums/general-m...ing-noice.html

https://ls1tech.com/forums/generatio...ng-normal.html


Thoughts? Inputs?

Its been a while since I buttoned the oil pan up the last time and I can't remember how I did it..... What's the procedure for getting the oil pan back in correctly now that it's in the vehicle with a trans behind it???? The bellhousing ought to keep it from hanging towards the back of the engine too far right??????

ElQueFør

129 views and nothing?


I guess I'll know soon enough when I drop the pan and pull the pickup tube.

G Atsma

Rule of thumb: The fatter O-ring goes on the tube with an indented "groove" around it where the O-ring goes, and the thinner O-ring goes on those tubes without the groove

ElQueFør

Thanks for the reply!

I seem to recall using the blue thinner O-ring when I put the pickup tube in several months ago. I know you can't always go by color..... But the first design (thinner) O-ring is usually blue (or so I've read).

This 6.0 is out of a 2003 or 2004 truck so that would mean that it would have to have the revised pickup tube with the fatter O-ring right?

I can't find the original posting, but it's repeated here: But anyways, if it's true, the ONLY trucks that used the early thinner style O-ring were the EARLY 99-00 models..... I'd think that since this 6.0 I have is either an 03 or 04 it HAS to have the revised pickup tube design using the fatter O ring wouldn't you think???????
https://ls1tech.com/forums/generatio...mp-o-ring.html

Like I said though, seeing bubbles on the dipstick after warm, and the come and go lifter noise really makes me thing I botched the O-ring somehow, either pinched it, and or used the wrong one from the get go. What do you think?

G Atsma

Yeah, if you're getting bubbly oil and intermittent lifter tick, the O-ring is likely your culprit.

ElQueFør

Appreciate it man.

I'll know today or tomorrow, whenever I get time to drop the pan and see!

ElQueFør

Well it sure looks like I used the wrong O ring..... Since this pickup tube has the groove I need to use the second design O ring right?

Just looking for a little additional reassurance before I put this thing back together.
12557752 is the first design, usually blue. 12584922 is the second design, usually red/orange and is to be used on ANY pickup tube with a groove in it do I have this correct?




Found these specs on another thread:

1st design) Oil Pick-Up Tube O-Ring 12557752
Chevy/GMC Pick-Up (1999-2000 LS V8) 1st design
F-Body (1998-2002)
Cadillac CTS-V (2004-2007)
Corvette (1997-2008)
Thickness = 3.55mm (0.140")
ID = 23.60mm (0.930")

2nd design) Oil Pick-Up Tube O-Ring 12584922
Chevy/GMC Pick-Up (1999-2000 LS V8 engines with 2nd design pick-up tube)
Trailblazer (2003-2008 With LS V8 engine)
Hummer H2 (2003-2008)
Hummer H3 (2008 With LS V8 engine)
Chevy/GMC Pick-Up (2001-2008 LS V8 engines)
W- Body (2006-2008 With LS V8 engine - Impala, Lacrosse, Grand Prix)
Thickness = 4.20mm (0.165")
ID = 20.69mm (0.815")

G Atsma

Yup, fat guy goes in the groove...

ElQueFør

Thankyou!!

I should have this job finished up tonight. I also ended up adding a girdle since I was in there. Kind of spendy for a little piece of aluminum, and I had to modify the pickup tube holddown to make it work by grinding some off of the side where it was hitting, and I had to grind off the little 3 armed tab thing.


I was thinking about this..... I was wondering if anyone had brazed the pickup tube to the pump itself. And then added a v band on the tube so that you could still disconnect it. The whole O-ring thing just seems like a stupid design, but using the wrong one doesn't help!!!

G Atsma

When assembled CORRECTLY, which isn't that hard, the design is pretty smart and an inexpensive, effective design.

ElQueFør

Well I'm reporting back with good news. My hot idle oil pressure is 40+ psi, 60 70 sometimes nearly 80 PSI on acceleration. And so far no more lifter tick.

I guess now I gotta learn what noises are normal for these LS engines, but they are NOISY

Thanks G Atsma!

youngengines

I'm glad to read the oring helped.. I was worried you may have a cam bearing problem,

ElQueFør

Well, I wouldn't think there would be anything wrong with the cam bearings simply based on the fact that when I had this engine on the stand, I took both heads off for LS9 gaskets and ARP bolts, and; I had the pan off then also.

There is still crosshatch visible in the bores from the factory honing process. And from just inspecting everywhere I could see with the heads and oil pan off, the inside of the engine was very very clean, no sludge buildup whatsoever!!!! It looks like whoever was maintaining this engine before I got a hold of it really took care of it, and/or these LS engines are just that tough

joecar

He was referring to the cam bearings being known to walk under some conditions, this causes an internal oil leak.

ElQueFør

Oh I see. You mean they move around in the cam bearing bores and thereby causes internal pressure to drop?