QSUD in Ecotec: 2 qts. consumed in 3K !

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Originally Posted By: WobblyElvis
Is the throttle valve covered in oil? If so, the engine is ingesting oil from the PCV system and the rings may be allowing too much blow-by.

If the air filter has been changed in the last couple of years and looks clean, I doubt it is causing problems.

I do understand that some oils are more easily consumed than others. Some people say that when switching oils, often there is increased consumption until the engine "settles into this oil" and then consumption returns to normal. I find this hard to believe but I'm willing to learn how this could happen.

The cartridge style oil filter is contained in a cavity cast into the block in a relatively high position and there is no anti-drain back valve. I find the filter cavity drains over time and the oil level in the sump rises considerably if left overnight. . . .

My oil level checks over the last two years all showed oil at the proper point on the dipstick when I'd check a few minutes after shutting the car off. If what you say is true, I'd have seen a low level, even a dry stick, before. But Sunday was the first time I'd ever seen the level so low.

I'll need to investigate the throttle valve and have a look at the air filter, too.

The logical thing to do, if there are no clues elsewhere, is to go back to the AC Delco dexos synblend for an interval and see what happens.
 
These ecotecs dont have a pcv valve. Just a tube that runs from the cam cover to the intake manifold. By design the throttle plate will get covered in carbon and oil. They are very simple to remove and clean. If youre a DIYer i must warn you, with 60,000 + miles it will be extrememly covered in soot. Not to worry.

Proper oil change intervals go a long way to prevent too much buildup before it next cleaning.
 
Originally Posted By: WobblyElvis
Is the throttle valve covered in oil? If so, the engine is ingesting oil from the PCV system and the rings may be allowing too much blow-by.

If the air filter has been changed in the last couple of years and looks clean, I doubt it is causing problems.

I do understand that some oils are more easily consumed than others. Some people say that when switching oils, often there is increased consumption until the engine "settles into this oil" and then consumption returns to normal. I find this hard to believe but I'm willing to learn how this could happen.

The cartridge style oil filter is contained in a cavity cast into the block in a relatively high position and there is no anti-drain back valve. I find the filter cavity drains over time and the oil level in the sump rises considerably if left overnight. My guess is the oil leaves the oil filter housing two ways. Some drains back through the oil pump and some flows to the sump through the lower main bearings. However this occurs, I find the oil level varies greatly.


There is an anti drain back valve inside the engine as well. If your oil level is rising after the engine has been shut off and the oil filter cap is torqued correctly and no tears in the filter o-ring, then there is probably something wrong internally with that engine. The oil filter housing drains directly to the oil pan. This can be verified by draining the oil pan,have someone (or record a video) watch the oil drain when you loosen the filter. The oil from the filter housing will drain.

Im not sure where the internal anti drain back valve is to be honest. Ive only heard of maybe 1 go bad and it was from neglected OCI's. But if its bad then i can understand why the level goes up after shut off. The oil filter housing doesnt hold enough to show signifcantly on the dipstick.
 
OP, I would just monitor the oil level, maybe the QSUD is doing some cleaning?
 
Originally Posted By: stower17
These ecotecs dont have a pcv valve. Just a tube that runs from the cam cover to the intake manifold. By design the throttle plate will get covered in carbon and oil. They are very simple to remove and clean. If youre a DIYer i must warn you, with 60,000 + miles it will be extrememly covered in soot. Not to worry.

Proper oil change intervals go a long way to prevent too much buildup before it next cleaning.

I'm not much of a DIY guy any more, but I can take a look at it. Can you post a link to a video showing what I should be looking at once I take off the engine cover? I've searched on YouTube, but the throttle body/plate videos are all for different engines.
 
Originally Posted By: stower17
OP, I would just monitor the oil level, maybe the QSUD is doing some cleaning?

Something's happening in there. Even after I added the 2 new quarts, the oil shows up pretty black on the dipstick.
 
Same engine in my Terrain @ 70k started using rotella 40 wt...currently at 110k consumes 1qt every 5k.
 
Every once in while, one of mt ecotecs is a bit low on oil.

QSUD, M1, Napa Syn......

Owning these engines over a decade, they can be quirky when they want to be....should be more than fine.

All mine still run quite well.....
 
Update,

I switched out the engine air filter, which was not clogged or very dirty at all (but since I'd gone to the trouble to undog those screws, I went ahead and changed it). As for the engine cover, mine is different from the one in the video WobblyElvis posted; I couldn't get it off. But peering under the one corner I could lift, I saw that everything visible was clean, and there was no smell of oil. Nor is there any leaking oil under the engine. The car runs flawlessly and the gas mileage remains the same.

Plan: This week, swap the oil back to AC Delco 5W-30 dexos, the oil the Regal ran on without a hiccup for 2 years, and monitor the oil level very closely. Next time the car is in the shop for something, I'll ask my mechanic to look at that throttle body area and see what's what. Maybe it was just one of those "quirky" things. . . .
 
Visited the dealer this Saturday; oil change to 5W-30 AC Delco dexos semi-synth oil (plus tire rotation and "multi-point inspection," and they mentioned nothing that needed work). The level on the dipstick looked great when I picked up the car. Now, with the oil back to the baseline oil that worked for 2 years, I'll see how the level goes from now until October or so.
 
Originally Posted By: Garak
Originally Posted By: WobblyElvis
Would someone explain to me the mechanism by which more oil would be used when switching brands. Hard to believe it is true.

It's been observed often enough, but I've never seen a valid mechanism presented.
wink.gif


+1
Had an 06 Forester X that I used M1 from the first OC. Used 1/2 qt every 3k. Got a great deal on Castrol Edge and used 1 qt every 3k until I switched back to M1. Still only used 1/2 qt every 3k when I traded it in at 112k miles.
 
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Yep, it doesn't seem to make sense, but one sees it. And, as I've said, I've never seen a valid mechanism presented that doesn't fall apart in a few minutes. And some engines are different than others. The G37 has only had PYB and Delvac 1, and doesn't consume either.

The Audi would go from no measurable consumption to absolutely drinking the stuff, even with fairly similar viscosities. It was fine with 10w-30 PYB and most 40s. Yet, M1 5w-30 went down so fast I couldn't believe it.
 
After my experience with QSUD, that doesn't surprise me.

In my opinion, you can't get a worse oil unless you buy a convenience store off brand like City Star.
 
As soon as I drained that QSUD out and replaced it with Citgo 10W-30, the engine came back alive again. The engine became smoother; quieter, and more energetic. I'm thinking body builders probably have similar experiences going from one supplement to the another.
 
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