SRX OIL USE

[susanigks]

I purchased a used 2006 SRX with a little over 30,000 miles on it. I get it that this cars uses oil from all the info I have seen on line. I have never had a vehicle that I ever had to worry about the oil level. I do not have any evidence of a leak, so I have to assume that 1 qt every 2000 miles is what I have to live with. My issue is that on vacation, right after it was purchased my check engine light came on. Onstar ran test and said it had to be taken to a dealer. it hardly had any oil left in it...so with all the bells and whistles on it is there not any kind of warning that should say "oil level low"???

[BodybyFisher]

Something is wrong with this, if there was hardly any oil in it, you would definately have gotten a warning of low or no oil pressure. I DO NOT think that you got the check engine light for it having hardly any oil in it. If the oil level was that serious you would have gotten more serious messages

What did the dealer say the check engine light was for?

[winterset]

I can't inagine the "low oil" function being taken away from more modern N*'s. I can believe that your oil level sensor is not functioning correctly. My car is exactly 10 years older, and I suspect my sensor is not telling me when I am low. I guess the same problem can happen on newer cars too.

[Bruce Nunnally]

V6 or V8? The V6 oil level sensor was removed in 2006 or so.

[davedog]

I had a 2005 V6 SRX. Had/have similar issues. Got the car, assumed since it was new checking the oil level regularly was needed, was on a long trip home, had weird engine behavior, stuttering, oil pressure low light came on (no warning of it being low ahead of time).... Took to dealership, oil level was VERY low. They tested oil consumption, said within spec, No leaks, filled her back up - no more problems. I just make sure to check the oil often. It does use oil - but I have figured out how to DRASTICALLY reduce the amount it chews through: The dipstick has a full, and add marks, with one tick mark in between. Instead of running at full, run at the halfway point - you will be amazed at the difference! Have had this car 5 years now - just now figured this out!

Wish i had seen all the info on the problem online before warranty ran out - would have made a bigger stink. Totally unacceptable.

[ruralliving]

I purchased my used 2006 Cadillac SRX in September '09 with a little over 30,000 miles on it. My first experience with low oil came in January '10, and of course, the warranty ran out in December '09. I had noticed that it was running poorly, so I stopped in to have a mechanic look at it to see if he had any idea what could be wrong with it. Based on the behavior of the engine, he thought it was a timing chain issue and advised me to take it to an authorized GM repair center. It was running so poorly, I decided to have it towed to the repair center so that I wouldn't damage the engine any further. Low and behold, they told me, it had low oil and this was a very common problem with these vehicles. Since the timing chain adjusters were hydraulic, it would mimic a timing chain issue.

Now this vehicle can monitor my tire pressure, but it can't tell me if I have critically low oil levels?

I have been monitoring my oil ever since and have determined that it uses 1 quart of Mobile One Synthetic 10W-5 oil every 1000 miles. No blue smoke, nothing, the oil just disappears. First vehicle ever owned that uses so much oil!

[Bruce Nunnally]

I have come to think that high-revving DOHC VVT engines don't really like or do as well when they are babied all the time. See discussion here which is about the Northstar V8 but similar things apply for any high-revving DOHC engine.

Piston rings normally move around quite a bit, and seal between the pistons and the cylinders:

Piston rings in engines achieve efficient sealing with both the cylinder wall in a radial direction and the top or bottom sides of the piston ring grooves in an axial direction. The contact pressure on the cylinder wall is achieved by the inherent spring force of the ring in conjunction with the gas pressure behind the ring. The contact on the side of the piston groove is achieved by the axial forces acting on the ring. The axial forces are composed of the gas pressure above and under the ring, the mass forces (inertia), and the friction forces. These forces change their direction during the cycle. As a result, the piston ring moves from one side of the groove to the other during the cycle.

UNDERSTANDING THE FUNDAMENTALS OF PISTON RING AXIAL MOTION AND TWIST AND THE EFFECTS ON BLOW-BY

Sometimes high oil usage can be caused by the build-up of deposits on the piston rings, causing the rings to stick or not slide as smoothly.

One solution is a top-engine cleaning procedure that the Dealer can do.

However, my preference is to drive the car spiritedly for a few wide open throttle acceleration runs with the transmission in sport mode. See Reference. Also ensure your PCV valve is fresh and new. Further, actual measurement of oil level has to be done in controlled conditions and circumstances in order to have consistently comparable results.

Sport mode; Full throttle, 30-65 mph, glide back to 30 on engine compression, full throttle 30-65, repeat. The idea is to apply full pressure to the rings from each direction in order to clean off any deposits and get full ring movement in their grooves.

Please log your oil usage every 500 miles for 2000 miles, then try a solution above, and then log again every 500 miles for 2000 miles, like a science experiment. I see that this thread gets a lot of attention, so maybe we can learn more about what works well for the V6 engines too.

[edelen]

good job you gave enough info that gm engineer might not be able to keep up with, but i understood most of it and i will try it because i do baby my 3.6 cts arround, but what i want to know is where did you devise such a plan, looks like some one came up with a plan that knows quite a bit about the 3.6 motor and potienal problems, does someone or GM advise any kind of additive that might do something simular for the piston rings. THANKS for your post i really enjoyed reading it, could be the awnser to alot of 3.6 v6 oil consumption

[Bernard Boule]

Something is wrong with this, if there was hardly any oil in it, you would definately have gotten a warning of low or no oil pressure. I DO NOT think that you got the check engine light for it having hardly any oil in it. If the oil level was that serious you would have gotten more serious messages

What did the dealer say the check engine light was for?

I had the same problem. Had changed the oil myself after 4600 mi engine started to surge and make noise. I took it to dealer he said I'd ruined the engine by running it with no oil. I had seen no low oil notice or low oil pressure indication and check engine had come on just before I took it to the dealership. Days after the surging and noise started.

[zedhead]

Newb here at caddyinfo, but I had to sign up when I read this post. I'm currently in the market for a CTS4 Wagon for my wife. Was doing a little research and ended up here. I'm a 50 YO male that has been turning wrenches since I was 10. I've rebuilt 10-15 engines in my life, and have maintained every car/truck I've ever owned.

Here's my take on the 3.6 oil consumption.

Simply put, if an engine consumes more than 1 qt of oil between 3K mile oil changes, there is a problem somewhere inside the engine. When Cadillac says that more than that is normal, they're trying to cover their... um... yeah. GM has gotten really good at this after all the intake manifold failures with millions of 3800 II's.

IMO there are 2 likely culprits.

The first would be piston rings. If a piston ring does not seal tightly enough against the cylinder wall, during the compression stroke some of the compressed air/fuel will slip by the rings/cyl wall. This air then travels to the crank case. Modern engines use a positive crankcase ventilation (PCV) system to address this compressed air. Without it, the crankcase would pressurize and the air would find the least resistant route to escape the crank case. Usually pushing past an oil seal.

With the PCV system the pressure is routed back into the inake manifold to be re- burned. When it does this, it carries vaporized oil with it. When the vaporized oil hits the cooler intake manifold it condenses back into a liquid. So a little intake/PCV inspection would show signs of oil contamination it this was the case. An engine compression leak down test would comfirm/deny this condition.

The second would be valve stem seals. These are small seals that keep the oil from traveling past the valve stem into the combustion chamber. This is a little tougher to diagnose. But most of the time, it will show with a small puff of blue smoke on cold start.

If I had an engine with excessive oil consumtion, these are what I'd be looking to diagnose first. GM denying any problem is not what I'd settle for. Remember the greasy wheel anology? GM hates noisy wheels.

I've read other posts about trying to solve this, assuming sticky rings, using a hard throttle approach to heat the rings and burn off any gunk accumulated on/in the rings. I'd advise against that approach, and try this: http://www.auto-rx.com/ I've used this product on my diesel trucks with great results.

[Z15]

What oil are you using? Viscosity and brand?

I had a 2005 CTS with 3.6L, never used oil in 30,000 miles. My current 20099 CTS 3.6L has not used any oil in 28,000 miles. They may have gone down a tad but never reaching 1/2 qt. I use nothing but 100% synthetic. Synthetic oil was the factory fill in both my 2005 and 2009 and if you are using regular petroluem then you are using the wrong oil.

Some oils will lose volume from the heat of the engine, its called Volatility. The accepted rate is 15% which means the oil can lose 15% of its volume and still me specifications set by the API. Typically that means about 1 qts in 3,000 miles although GM considers 1 qt is 2,000 miles to be normal. And its not just GM, every oem uses 2000 miles as the baseline. Its completely normal to consume oil with some oils.

Why might I have to add oil between changes?

Btw - The synthetic oil I use has a volatility rate below 7%.