Changing the PCV valve seems to have affected the transmission. I posted another thread regarding this. I had been experiencing harsh shift since I purchased the vehicle. That’s gone now, or appears to be.
2000 Silverado 5.3L oil consumption
- Thread starter otis24
- Start date
BrendanC
$100 site donor 2024
check all of the hoses really well on the PCV system. they like to split with age. there is one on the throttle body to passenger side valve cover and the bit going to that pcv valve.
Don't hold me to this but I believe the earlier ones still used a PCV valve from 99-02 but there were some changes with the 03-04 models which is mostly the electronic throttle body but the valve cover change is most likely from that same timeframe and they went to using the orifice, over time they get gummed up. I have a 2004 GMC w/ 5.3 that only goes through 1 qt between changes but it does have just over 120k miles so it's barely broken in. When I got the truck it had 42k and all I've used is PP 5w30 or RGT.
I need to replace the dreaded knock sensors and will look into the updated valve cover while I'm in there.
I need to replace the dreaded knock sensors and will look into the updated valve cover while I'm in there.
How necessary is it to change out the valve cover to the updated one with the baffle? I didn’t change mine out. Only the updated PCV.
BrendanC
$100 site donor 2024
i didn’t change my valve covers. original 2002 with 238k miles. i get a little oil in my catch can but nothing serious. can’t ever see any movement on the dipstick.
I installed the Dorman one and it fixed the oil consumption and smoke but the original was sludged up from coolant intrusion. I imagine if I didn't have the problematic castech heads leaking coolant internally then I would never have had any consumption anyway.
Now I add zero oil but have to add coolant every few weeks. At 270k miles/433,000kms I'm just getting ready to swap a lower mileage spare 5.3 I have. Hopefully I get to 500,000kms before I have to do that.
Great suggestions, it could be the VRP as well. I ran an OCI in our '18 CX-9 and it used 3/4-1qt over about 5k miles. We've owned it from 36K and it has never used any oil. Current fill of PP 5w30 hasn't used any so far in about 3,000 miles 
I'm thinking of running VRP next change just to see if it repeats.
I'm thinking of running VRP next change just to see if it repeats.
I changed oil this weekend. Earlier than I normally would have. Had about 5k this OCI. OLM was saying to change oil and I was on the “rinse cycle “ following an Auto-Rx retreatment. Switched back to Mobil1 FS. Also picked up the old style PCV valve. Will monitor for usage.
I would say stop putting crap into the oil, use it 100% from the bottle to start.
That has not been my experience with LS. Not even close
BrendanC
$100 site donor 2024
why are you changing back to the check ball PCV?
Care to elaborate? That's what GM pushed around those years & that was really close to what my 1998 Eldorado went through from 50k to 99k. Granted that was 300 HP high compression engine of the era. I've never owned a 5.3 but many 5.7's.
The 5.7 350 and the 5.3 are completely different things. Your eldorado had neither.
I have seen countless LS engines used under very severe conditions that did not use 1 quart per 1000 miles maybe a 1\2 quart per 5000k was the norm. Factory engine, not some built abomination
Not changing back at this time. If consumption continues, I may swap out PCVs to see if it makes a difference. If no difference, I will put the new style PCV back in and look at installing the updated valve cover to see if that improves things.
BrendanC
$100 site donor 2024
can also echo this. my truck nor none of the LS powered trucks in the fleet burns any oil. we have trucks in excess of 14k engine hours that don’t burn anything.
Yeah, the Eldorado quoted above to my knowledge never had an LS. Northstar 4.6 which did have some oil issues to my knowledge. I think there is a disconnect here between facts.
For a company I used to work for, I was mildly responsible to truck maintenance schedules and minor repair, such as water pumps and belts, alternators, oil OCIs and the like, nothing major. Mostly I checked to make sure the trucks were up to date on OCI, and took them to local mech if need be.
The 6.0 Vortec constituted most of the fleet, of maybe 30 trucks, and none had any oil burning issues, or much else for that matter. Trucks were sold at 5-7 years old, and 150-200k, depending on several factors, none of which were typically mechanical, but business minded reasons.
3-5 K oil changes at a VIOC change spot down the road from the shop. Bulk 5w30, whatever that meant.
I know they are different. I'm just reiterating what GM at the time was claiming for the GM vehicles or at least the N* engines. Just to note there is a difference between what an OEM considers "Normal" oil consumption vs what you may see for yourself. You may never have a problem but for the folks that have high oil consumption the OEM's can have very disappointing response of "It's normal at x miles/1 qt. 5.3L being low powered truck engine should do better than the N* I'd imagine.
Higher Than Expected Engine Oil Consumption (Replace PCV Valve) #01-06-01-029B - (07/19/2002)
Higher than Expected Engine Oil Consumption (Replace PCV Valve)
2002 Chevrolet Avalanche
1999-2002 Chevrolet Silverado, Suburban, Tahoe Models
2002 Cadillac Escalade, Escalade EXT
1999-2002 GMC Denali, Sierra, Suburban, Yukon Models
with 4.8L, 5.3L or 6.0L Engine (VINs V, T, N, U -- RPOs LR4, LM7, LQ9, LQ4)
This bulletin is being revised to clarify the parts information. Please discard Corporate Bulletin Number 01-06-01-029A (Section 06 -- Engine/Propulsion System).
Condition
Some customers may comment on higher than expected engine oil consumption. They may further comment on consumption in the range of 3,200 km (2,000 mi) or less per quart (0.946 liter) of oil under normal driving conditions.
Cause
The condition may be due to the positive crankcase ventilation (PCV) valve flow rate under certain engine operating conditions.
Correction
Verify that the oil consumption is not the result of an oil leak or other engine concern.
The dealer should perform an oil consumption test. The vehicle should have accumulated over 6,450 km (4,000 mi) before establishing the oil consumption rate. Reference Corporate Bulletin Number 01-06-01-011, Information on Engine Oil Consumption Guideline, for details.
Remove the PCV valve and inspect the hose going to the intake manifold for signs of excessive oil being present.
If excessive oil is present in the PCV hose, replace the PCV valve (Type 948C) (2) with a new-style fixed orifice PCV valve, GM P/N 12572717(1). See the illustration below.
FIGURE PCV Valve Identification(c)
(1) New style fixed orifice PCV Valve
(2) Spring and plunger style PCV Valve (Type 948-C)
Important
The new style fixed orifice PCV valve contains no moving parts, and does not rattle when shaken.
If the vehicle has an orifice style PCV valve, investigate other causes for high oil consumption.
Parts Information
Part Number
Description
Qty
12572717
Valve, PCV
1
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
J6000
Valve, PCV - Replace
Use published labor operation time
Around those years? That's just what most manufacturers say to keep warranty costs down. It was true for Ford of the era. Just because they have a statement saying that doesn't mean it's normal.
Yep, keep in mind this poster mentioned their truck has almost 190k on the engine. I'd say it has plenty of leaks & burns some oil. Obviously, it's well out of warranty so GM's statements are moot but noteworthy.
I'm just saying that it's not specific to those vehicles. I have basically the same engine with 270k miles and it uses basically no oil. It used around a qt per 3k miles when it needed that replacement valve cover still.
All I'm saying is that their "normal oil consumption rate" has nothing to do with what you should expect out of that engine and more to do with them avoiding warranty costs on the odd engine that does use oil.
