tech2

good points. that is why fuel injection and intake cleaning maintenance should be done on di engines. try selling it to people; it like pulling teeth to convince them.

Frank3

So the oil monitor basically counts down using various criteria for short trips, cold trips, etc. until zero is reached. Since the level is set by GM, I assume it relies on the fact that their synthetic dexoil is being used. I thought it was safe to run 7000 - 10000 miles on synthetic oil. If you use conventional oil, I would suspect that you should change the oil at a more frequent interval, no?

bigbadbowtiegirl

With new EPA regulations on fuel economy, engineers are having to get more computer control involved to meet the new regulations being imposed on new car dealers. If you refer to your owner manual it states that even with relying on the Oil life monitor, NEVER to let it get past 7500 miles between oil changes. Short trip driving on the car with mostly city driving will cause your oil life to drop faster. There is no sensor that monitors the condition of the oil in a car. The oil life monitor system is a mathematical algorithm the takes in to account things like mileage, engine temp, outside temp, rpms and many more things. But cannot be relied on as a 100% fail safe. Also take into account that these new aluminum motors have approx a 25k break in period unlike the older motors. As to the PCV issue everyone is talking about. The gas issue with it not breaking down properly has a lot to do with the large amount of ethanol in our fuels today. Most manufacturers are working on finding away around this issue but have been unsuccessful.

bigbadbowtiegirl

Directly from the owners manual:
When the system has calculated that oil life has been diminished, it indicates that an oil change is necessary. A CHANGE ENGINE OIL SOON message comes on. See Engine Oil Messages. Change the oil as soon as possible within the next 1 000 km (600 mi). It is possible that, if driving under the best conditions, the oil life system might indicate that an oil change is not necessary for up to a year. The engine oil and filter must be changed at least once a year and at this time the system must be reset. Your dealer has trained service people who will perform this work and reset the system. It is also important to check the oil regularly over the course of an oil drain interval and keep it at the proper level.

If the system is ever reset accidentally, the oil must be changed at 5 000 km (3,000 mi) since the last oil change

blue-impala

I am not sure what the ethanol content has to do with the oil coking on the intake valves. The fuel no longer passes over the intake valves. It is injected directly into the cylinder after the intake valve. The intake valve no longer gets sprayed with fuel, just air and PCV gasses pass over the intake valve on a direct injected engine.

As for the PCV gasses, they are comprised of blow by (combustion gasses that leak by the piston rings during the power stroke and oil vapor that comes from the crankcase. This has been the case with engines since they were invented.

A good read for those that do not understand the PCV system well.
HowStuffWorks "How does a positive crankcase ventilation (PCV) system work?"

bigbadbowtiegirl

The problems with the fuels and ethanol have a lot to do with the pcv system. The carbon build up that these fuels are causing are clogging the pcv systems. Seen it a hundred times over already.

Those pictures are from a 3.6L that only had 29k on it.

blue-impala

The fuel is not causing this as it is does not even come in contact with the back side of the intake valve on a direct injected engine. The build up shown on the back side of the valves on those pictures is caused by the oil vapors from the PCV gasses hitting the backside of the valves and getting baked onto the valves (coking). The problem is the lack of fuel passing over the valves and washing away a lot of that residue. This was not a real problem during the days of carburetors, throttle body fuel injection or port fuel injection as those systems allowed the fuel air mixture to pass over the intake valve and the detergents in the fuel would help keep them clean. With direct injection, the fuel is sprayed directly into the cylinder bypassing the intake valve. The fuel does not clean the valve because it does not touch it. The only thing passing through the intake valve now is air and the PCV gasses. This is not a issue of ethanol usage, the problem would exist no matter what type of gas was used. Ethanol lowers the efficiency of the gas a bit depending on the percentage, can lower the octane rating a bit and will attack rubber parts if they are not designed for it. It burns cleaner than gasoline, reduces emissions and actually has less of a carbon footprint than pure gasoline. I do not care for it as it lessens the efficiency of gasoline and causes problems with older vehicles. It is not the cause of build up on the intake valves.

This why some people are using a Oil Catch Can system to try and catch the oil vapor and separate it out of the PCV gasses before it goes into the intake manifold and causes the issue with the intake valves. It is an issue for any direct injected engine, be it GM , Ford, Volkswagen or any any others unless the manufacture has designed a system to combat it. The Oil Catch Can, if well designed is very effective, but the manufactures will not embrace it due to added cost and the added maintenance, the can needs to be emptied periodically.

jaha40

4700 miles til my first oil change, '14 2LT. Doesn't bother me at all

EYEL1NER

The car just hit 4700. I'm taking it in to the dealership for an oil change in about 20 minutes; called first thing this morning and got an appt.
I also need to have them take a look at the driverside seat while I am in there. The first button that moves the seat, the forward/backward/tilt/raise/lower button, does not fully work. I set the seats for myself and my wife after buying the car in September and have lost some weight while outside the country. When my wife picked me up at the airport, I chose my preset position and decided that it was not as comfortable as when I first set it and I needed to adjust it. After manually repositioning it all weekend, I got the manual out and readjusted it. While looking in the manual though, I see that the first button is 8 way adjust. Mine will go forward and backward no problem and the rear part of the button will toggle up and down to raise and lower the rear part of the seat. The front part of the button goes up and down, but does nothing. According to the book, that raises and lowers the front half of the seat, adjusting the tilt differently than the titling the rear portion. Or it could possibly raise or lower the entire seat. It only has arrows going up and down.
When I first adjusted the seat after buying it, I thought it odd that the front portion of the button did nothing. Apparently it is supposed to though.

Anyway, loving the car. I have already spent more time with it since Friday than I did after buying it. Can't wait for my drive to Missouri now; before I was dreading that long a drive and it will still be boring, but at least I will be comfortable. I am having a really good time driving it and am very happy with my purchase. It just feels a bit awkward to drive still, since I had not driven since I left the country. Getting slowly more used to it though. I wish I lived somewhere where the other people on the road were not morons...

tech2

unfortunately some people go way over that mileage. $40 000 for a vehicle and destroy it for lack of a $30 oil change. the vvt camshaft actuators are all operated by oil pressure...get gunk the the screens and see how well they work. guess if you only keep your cars for a short time it doesn't matter.