Ls 5.3 6.0 oil consumption and fix

[OKGMC4]

I had a 2001 5.3l in my 56 for 7 years that never used a drop of oil. I swapped it for a 2005 6.0 and it started gulping oil by the quart. It was sucking it through the pcv hose into the intake where it was being pulled into the engine. I had an oil fouled MAP sensor that was causing both engine AND trans shifting issues. It's no fun when your tranny shifts so hard at 25mph that you think it literally exploded and you have to make sure nothing came through the floor and severed your leg. After I did a ton of google duty I found I wasn't the only one who has an LS engine that uses oil or has found oil in the intake. The gist of this post is that most of the time nobody has seemed to find an answer to this other than getting an oil catch can.

[OKGMC4]

I started with a catch can. I could fill it up in a day or two. It filled up to the top once and the next time I started the engine it smoked like it had completely worn valve guides for two whole minutes. I rebuilt this engine myself so I know its all good. I checked it out anyhow...came up with 3 percent on each cylinder on a leak down test. I even ran a borescope from work into the cylinders. The plugs were wet when they came out and you could see where there was oil pooling at the bottom of the cylinder before being burned out on startup. So why was this engine sucking all it's oil into the intake?

[OKGMC4]

Early LS engines came with pcv valves. Like my 01 5.3 engine. It still has the original pcv valve and it works fine at 80K miles. Somewhere around 02 or 03 GM decided to remove the functional pcv valve and replace it with a pressed in barb with only a tiny fixed orifice to control vacuum and oil movement. This is what my 2005 engine came with. You can see the tiny little hole in there. It doesn't adjust to vacuum load like an actual spring check would. I wanted to convert to an old style pcv but you can't buy them anymore for this application and using one for another engine application might or might not work. Every engine design can have a different vacuum signal. The one they sell as a 5.3 replacement is nothing but a metal can with a fixed orifice hole in it to shove into an old style valve cover. They don't even list a part number for the grommet that holds the valve in the cover anymore!

[OKGMC4]

I already had an old style valve cover off a 1999 engine so I bought a grommet at OReillys on the Help! section, part number 42313. It says it fits pretty much all 2.8, 3.1, and 3.4 GM V6 engines but it worked great for me.

[OKGMC4]

And for a pcv valve I bought an ME Wagner adjustable dual circuit valve. It's tuned using engine size and idle vacuum so you set it to your specific engine. Cleanable, rebuildable, and the support is top notch. Installed in the standard 3/4 valve cover grommet and set it and then drove 300 miles to verify it worked.

[OKGMC4]

After 300 miles instead of filling the cup with oil I just had a little condensation in there. I noticed better throttle response as well and power seemed to be better. If your pulling oil into the cylinders I bet the ecm is pulling timing so it makes sense. That valve worked for me so I feel it was worth the $130 it cost. Before anyone bad mouths the price I counter with the fact that we spend thousands of dollars on our trucks on parts like engines and wheels, so why wouldn't you spend a few more dollars on a proven part to make it run better? Anyhow, I just wanted to share my journey with this oil usage problem and also what I found to be the fix in my case. I understand the 07 and newer engines with AFM have their own issues but this should be perfect on the 99-06 LS motors as long as you don't have other mechanical issues causing excessive blow by. Thanks for reading!

[Warrens69GMC]

Cool info. I might need this later....

[solidaxel]

Do you have a part # for the valve?
Thanks for the info

[PGSigns]

Good job on the write up. I am sure this will help others.
Jimmy

[geezer#99]

Originally Posted by solidaxel

Do you have a part # for the valve?
Thanks for the info

Here’s their site.
http://mewagner.com/?p=444

[SunSoaked]

I have the Wagner valve as well, just haven't installed it yet due to so many other mods I've been doing. I did my research and have no regret on the purchase despite the price. Quality is top notch and I expect it to function just as well.

[truckdude239]

THERE IS ALSO A DROP IN PCV VALVE FOR THE OLDER LS THAT JUST HAS A SMALL HOLE DRILLED IN IT I WENT FROM LOSING 3-4 QTS OF OIL ON MY 2002 SUBURBAN EVERY3K TO 2QTS THAT LEAKS FROM REAR MAIN AND OIL PAN GASKET

GM TSB #01-06-01-029B

https://shop.advanceautoparts.com/p/...484/10099183-P

[OKGMC4]

Originally Posted by truckdude239

THERE IS ALSO A DROP IN PCV VALVE FOR THE OLDER LS THAT JUST HAS A SMALL HOLE DRILLED IN IT I WENT FROM LOSING 3-4 QTS OF OIL ON MY 2002 SUBURBAN EVERY3K TO 2QTS THAT LEAKS FROM REAR MAIN AND OIL PAN GASKET

GM TSB #01-06-01-029B

https://shop.advanceautoparts.com/p/...484/10099183-P

That's the fixed orifice valve I was talking about. It's really just a hole, not an actual valve. Gm also tried three different baffle designs on multiple valve cover revisions but none of those had a functional valve either. Out of curiosity, have you pulled the throttle body and looked into the intake to see if you can see any oil wetness inside? Your pan gasket and rear main might be leaking but it's possible that they aren't as leaky as you think and some of that 2 quarts is still getting sucked though the intake. I know a little oil leak can look like a lot once everything gets wet and dirty. My 5.3 with a functional pcv valve doesn't use one drop of oil in a 5k oil change and the intake is absolutely dry.

[truckdude239]

Originally Posted by OKGMC4

That's the fixed orifice valve I was talking about. It's really just a hole, not an actual valve. Gm also tried three different baffle designs on multiple valve cover revisions but none of those had a functional valve either. Out of curiosity, have you pulled the throttle body and looked into the intake to see if you can see any oil wetness inside? Your pan gasket and rear main might be leaking but it's possible that they aren't as leaky as you think and some of that 2 quarts is still getting sucked though the intake. I know a little oil leak can look like a lot once everything gets wet and dirty. My 5.3 with a functional pcv valve doesn't use one drop of oil in a 5k oil change and the intake is absolutely dry.

I replaced it when i did intake and knock sensors so i havent really looked into it anymore but the gravel under my subburan is black with oil so that where most of my oil is going now i really need to pull tran or engine and just do a complete reseal