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Free and Fast Oil Consumption Mod/ Fix in Ten Easy Steps

73K views 134 replies 33 participants last post by  alacran 
#1 · (Edited)
OK, on the CTS board, there are a couple of guys with LY7s that claim they have fixed their oil consumption problem by modding their PCV orifice fitting. I just performed this mod - it is ridiculously easy and fast, and if you are well-equipped (tools, get your mind out of the gutter) it shouldn't cost anything.

The PCV orifice fitting lives in the right (passenger's side) valve cover, in the rear. It has a hose that clips onto it. The fitting is shaped like a PCV valve, only the neck is narrower and the base has two holes instead of one. It has no valve, but is continuously letting crankcase vapors pass.

The mod is to drill out two of the three holes to 7/64". My theory (and I haven't proven it yet) is that by opening up the holes, you reduce the velocity of the air flowing through the system, decreasing the amount of oil in suspension, and thereby reducing the amount burned off.

I used the following tools - a pair of medium sized vice grip pliers, a 7/64" drill bit and drill, a deep well 13mm 3/4" drive socket, a short 3/4" drive extension, a soft mallet, and some sealant (like Permatex Ultra Grey).

Step One: Displace (but do not remove) the engine cover by removing the power steering and oil filler caps and pulling up on the cover (it just snaps off and snaps back in):



Step Two: Remove the PCV hose by pulling back on the clip and pulling up on the hose end:











Step Three: Adjust the vice grip pliers so that it grips the flange on the PCV fitting neck. Don't go crazy or you will be buying a new one, and they are on national back order:





Step Four: Wiggle the vice grips side-to-side while pulling up. This shouldn't take much effort.





 
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#88 ·
If the oil ingestion is not stopped, then the causes of consumption cannot reverse themselves either.

The drill mod prevents the oil laden crankcase vapors from back flowing through the OEM cleanside lice intot he air box, but w/out a proper catchcan the cause of the deposits in the ring lands continues and if the rings cannot move freely to properly seat, then the oil consumption issue rarely improves.

The installation of a properly functioning catchcan stops the oil from ingesting via the intake air charge so it gives the rigns/lands a chance to free up over time (if not to gunked up) and that is whjen oil consumption will improve.
 
#91 ·
Not according to what the catch can manufacturer said previously.

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I remain skeptical that this actually reduces oil consumption. With the larger holes the PVC valve will likely react more quickly to crankcase pressure changes and therefore, increase air circulation may occur.
It's steel, not polyvinyl chloride. And it's not a valve, it's an orifice. I suspect the catalyst would take care of any issues with excess hydrocarbons.

If you are actually reducing oil consumption, you would be cleaning the exhaust pre-catalyst, thus furthering the purpose of the Clean Air Act. Perhaps the EPA could pay a reward to help recoup repair costs.
 
#90 ·
Depends on several factors, one being how well the rings seated intially. If the engine was broken in easy the first 500 miles odds are the rings never seated properly so that cant be fixed w/out removing the pistons and cutting a new crosshatch hone patteren into the cylinder walls. Also, if a DI engine the intake valve coking causes the valve guides to wear and this could be an issue. What it will do is stop further ingestion and give the rings a chance to free up so it should at the very least reduce the consumption over the next few thousand miles of use.

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:thumbsup:
 
#95 · (Edited)
As an experiment I fabricated a "catch-can" using an empty 14 oz. propane cylinder. Installed the pvc orifice mod (drill two holes, one top, one bottom, using 7/64" drill) BTW this does increase the holes noticeably from the 3 mm OE size. Ran this setup for 6500 miles, mostly interstate speeds. When I changed oil I was surprised to drain 8 oz. from the catch-can.
I've re-installed the stock OE pvc orifice and will run the same setup through the next oil change as a comparison of the two orifice setups.
I use Pennzoil Plat. 5W-30
There's been some discussion on the dipstick levels. 5 qts brought the level to the mid-hole on the dipstick. 6 to the upper. I'd assume if the dipstick shows only to the first hole I'd be 2 qts low.
When I changed the oil it appeared to be slightly less than a quart low during this oil change interval. I recovered a little over 5 qts (not including the 8 oz from the catch-can) to recycle to Walmart.
Prior to the orifice mod, oil useage was generally 1/2 qt or even less during a similar interval.
Any case recovering 8 oz in the catch-can was somewhat of a surprise.
 
#101 ·
#103 ·
I am curious what was the correct "break in" procedure for these engines? I didn't buy my SRX new... but I bought a new 04 Malibu and there was nothing special to do. I did change oil at 3,000 miles and always used Mobil 1. I often go 10k+ miles between oil changes, and the engine doesn't use any oil and runs like new. Oh yea... Malibu engine has a PCV valve.

There has been no special "break in" procedure on new vehicles for awhile now... unless I'm wrong?
 
#105 ·
Guys, sorry, I've been trying to follow this thread over 7 pages, but is drilling out the PCV valve and installing a catch can the magic bullet to keep me from putting in a quart every 750 miles or is a complete engine rebuild the only solution. The rebuild is GM's solution where as can a $200 catch can can do the same thing ?
 
#106 ·
so I had to check my 04 Malibu manual for break in... here's what it says...

New Vehicle Break-In
Notice: Your vehicle does not need an elaborate
“break-in.” But it will perform better in the long run
if you follow these guidelines:
• Do not drive at any one speed — fast or
slow — for the first 500 miles (805 km). Do not
make full-throttle starts.
• Avoid making hard stops for the first 200 miles
(322 km) or so. During this time your new
brake linings are not yet broken in. Hard stops
with new linings can mean premature wear
and earlier replacement. Follow this breaking-in
guideline every time you get new brake
linings.
• Do not tow a trailer during break-in. See Towing
a Trailer on page 4-40 for more information.

2007 SRX Manual says...

New Vehicle Break-In
Notice: Your vehicle does not need an elaborate
break-in. But it will perform better in the long
run if you follow these guidelines for the
first 500 miles (805 km):
• Do not drive at any one constant speed,
fast or slow.
• Do not exceed 70 mph (113 km/h).
• Do not make full-throttle starts; also refrain
from using the full throttle while driving.
Avoid downshifting to brake or slow
the vehicle.

I highly doubt you could damage anything unless you were towing a 7,000 trailer 85 mph out of the dealership on Day 1. Using dino oil instead of synthetic may cause issues, but I highly doubt it's a break-in issue.
 
#107 · (Edited)
cfishkin, I've got the rx catchcan, and did the pcv orifice mod. It has definitely helped. I'm still using oil, but about half of what I was going through before. Signifigantly, mileage has improved approx 1.5 mpg, and the engine seems to be running better. The big difference I have noticed is it pulls much better and doesn't downshift near as much for the same acceleration. SC has mentioned that it takes time for the engine to clean itself, and some may never do so dependent on their condition. I did not do this for performance, (I've got an 05 CTS 2.8!) but for better mileage, less oil consumption and better engine life. I recommend this step for anyone considering it. Ymmv.
(Meant to mention the rx catchcan is a nice bit of kit too. A solid product.)
 
#108 ·
Just an update:

GM now has changed the orfice size in the PCV barb to app the same size we have been sharing for years on this mod.

All LFX's now come (2013 april/may build dates) so I guess we did not know what we were doing.......and the new LT1 DI V8 for 2014 now comes with a "much improved oil separation system built into the valve covers to help reduce oil consumption and valve deposits".........LOL!
 
#116 ·
Pics are not viewable in this thread. I thought these engine don't have the typical pcv , & this is why it never get change just maintain.
PS my 3.6 v6 srx has 150000+ miles & have no oil consumption, always use Mobil 1 syn oil, I follow the dic recommendations & haven't had any mechanical issues of any types
 
#117 ·
There is a pcv fitting you can drill out that is a fix for oil consumption with the catch can install. Also i do use Mobil 1 full synthetic and still have issues. Its not the oil but how the engine was broken in, at least thats what i have read from guys on here that have a lot of experience.
 
#120 ·
Definitely the first mod to do is the drill out of the PCV barb. This is the direct mod which will allow better breathing through your engine's pcv setup. The second mod should be the catch can as it will catch any sludge causing oil, contaminants, undesireables etc, which exist in that engine breathing mist. Both mods support each other, but the first one to do is the no cost one - drill out the pcv barb/fitting.
 
G
#123 ·
If you buy a cheap 10 dollar catch can, one that only has a in/out hole you may want to do both, but if you buy the high price catch cans with filters and check valves built in you do not need to. But it does not hurt to do both if you really want to. There is more to high end catch cans then a in/out hole.
 
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