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3 months ago I bought Cadillac CTS 2007 3.6 with 31k miles, next day I went to local garage and changed the oil, filters, etc.

I have driven 7k miles since and when driving last week car started feeling 'not right' I went to local halfords service to do diagnostics. Then discovered cylinders misfiring and only around 1 litre of oil in the engine.

I do drive it excessively (that should increase usage) still oil consumption sounds to much for what I am used to.
I didn't see any blue fumes coming out of exhaust, so engine would seem to not be leaking oil into combustion chamber.

Is such consumption considered to be normal? What oil consumption should I expect?.

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Unfortunately, oil consumption in these engines can be quite large. GM has put out service bulletins which says that engine use up to 1 quart per 2000 miles is perfectly normal. I found some information on the bulletin:

(NOTE: - I was unable to find the actual bulletin, but the following is an excerpt from it, which was copied into the forum link I provided above. Scroll down to entry #3 to find the bulletin in it's entirety.)

Aggressive Driving High Speed or High RPM Driving Aggressive driving and/or continuous driving at high speeds/high RPMs will increase oil consumption. Because this may not always be an everyday occurrence, it is hard to determine exactly how much the oil economy will be affected.

A higher rate of oil consumption is normal for vehicles equipped with manual transmissions that are driven aggressively. By "aggressive," we mean operation at high RPM (3,000 RPM to redline), with frequent use of engine braking (using the engine to slow the vehicle). Vehicles that are driven aggressively may consume engine oil at a rate of up to 0.946 L (1 quart) every 805 km (500 mi). This is normal for a vehicle that is driven aggressively. No repair is necessary. This characteristic does, however, require the owner to check the engine oil level at sufficiently frequent intervals, especially when driving aggressively, to assure the oil level remains within the recommended operating range. As the Owner's Manual recommends, you should check the oil level every time you get fuel.

While whether you or I feel this amount of consumption is wrong, GM doesn't seem to think so. It may or may not be a cop-out by GM in not having to fix the engines, but it is what it is. With the bulletin GM is saying to the consumer, live with it.

My suggestion to you is to ensure you are keeping up with the oil changes and ensure every time you stop for gas (if not sooner) you are checking the oil to see how much you'll need to add. Buy the oil by the case and call it a day. My 2006 Chevrolet Silverado suffers from the same fate, though not as extensive as what you are seeing. I use about 3 quarts per oil change. Since I use the oil life monitor to change the oil, I really don't know how many miles that is.

  • @MatasVaitkevicius - I don't know that it really comforted me any, lol! The main thing here is to just keep up on topping off your oil and you should be golden. – Pᴀᴜʟsᴛᴇʀ2 Jul 2 '15 at 11:56
  • Correct me if I'm wrong but the oil escapes through the PCV valve and gets burnt along with the air:gas mixture when returned to the intake manifold, right? If this is the case, wouldn't be highly advisable to install an oil catch can? Not that you could reuse it, but for the sake of performance and to avoid excessive carbon build-up. – Capsule Jul 2 '15 at 12:18
  • @Capsule - In general, if the PCV is accessible, this would be a perfect way to avoid a lot of oil usage. It seems that most of them do show a lot of oil puddling just past the PCV in the intake manifold. You may need a large catch can though ;-) – Pᴀᴜʟsᴛᴇʀ2 Jul 2 '15 at 12:20
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I had the same problem and I replaced the DRI er side valve cover the OEM cover has a round hole about e the lifter which squirts oil into your pcv and suck into your intake. The new modified valve cover mover the hole and uses lips around the square hole to divert the oil away from your PVC intake. The pcv intake on my Silverado is a fixed orifice on the intake valve. Also I used an and plug in to disable the AFM which I hated. Truck has 165k miles and burns less than a half quart in 3000 miles.

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I have a 2006 SRX with 255,000 kms. It uses a litre of oil for every 500kms and has since I got it with 80,000. There are no leaks. this vehicle just burns oil although not visable from smoke. I have always been concerned about the high RPM's this engine operates at. At 110kms per hour the rpm is at 2200 to 2300 which seems high. My dodge Durango at the same speeds runs at 1800 rpm. Mo vehicle should burn this much oil. This is a poor engine design that was made either with inferior engine parts or just designed poorly. Best advice- don't buy one. I keep it because it is paid for and oil is cheaper than replacing it with something newer.

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Well, there then. The answer to the question is.... Buy a doorman drivers side valve cover for your CTS for 75.00 bucks, they moved the positive crankcase vent hole to the other end of the valve cover and baffled it so oil cant be sucked up the hose.I payed 1,150 for my 2006 CTS 2.8 a few little problems, in which one was, had a miss at idle, turned out it was they pulled the pcv line from air box and let it drained on the ground,but they forgot to plug the intake box, I put it back together for now,till I will probably drill a hole at the other end of my valve cover and add a pcv valve and plug the other end! Problem Solved!

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I disagree that it is normal to use up to 1qzt of oil for every 500 miles or even 1000 miles. My 15 years and 17 years old Japanese (Accord & Maxima) cars, both v6 did not indicate any drop of oil on the dip stick on every 3000 miles oil change interval.

  • You need to read the answer above - that relates to the manufacturer's information and their specifications. – Solar Mike Mar 21 '17 at 14:42
  • Mike, if you google search gm oil consumption, there will be bunch of posts related to this issue. Many drivers are not excessive driver but this engine's oil consumption take up 1 qzt of oil for 1000 to 2000 miles seems not right. – paul Jul 7 '17 at 19:07

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