: Question RE: low oil and engine light codes

04-16-13, 06:27 PM
So my 05 STS started bucking and making a grinding type noise over the weekend. Yesterday while driving, it started bucking very badly and the engine light came on and started flashing. Luckily I was right at work. Called the dealer and had it towed in. Today they state first that the car had no oil, (had the oil changed 1 month ago and see no signs of leaks) then they called back and stated it had 2 quarts. The said they filled the car with oil and it is running great. They also state that the engine codes were P0303, P0304, P0305. These all look like misfire codes to me. Does this make sense to anyone? Can very low oil cause these codes? Also just an FYI the oil light never came on and they see no issue with this. Also they have no idea how I lost 4 quarts of oil in 1 month. Any ideas from people would be grealy appreciated.

04-16-13, 06:36 PM
If this is a 3.6L you're probably burning it, well documented issue here on CF...I don't believe the 3.6 has an oil level sensor, time to use the dipstick...

These engines have VVT which relies on oil pressure to function. Low oil will most definitely cause misfire codes if it gets low enough.

I'd start checking it weekly to gauge how much oil your engine is using.

04-16-13, 07:35 PM
I think you are right, the STS only had an idiot light for low pressure, but not for low oil level. I check my oil level everytime I fill up just to be sure. Some have claimed they burn a few quarts in 1000 miles. I can't remember what GM claims is normal, 1qt every 2K miles? A couple people have had the piston rings replaced and said that stopped all oil burning and the car ran great. Of course, I think most of those were under warranty, as that would be a pricey bill to have to foot.

04-16-13, 07:41 PM
The rings got replaced in those engines because they were seized by carbon build up and could no longer move freely.

There is a fix for this oil useage issue somewhere on the CTS forum. It involves drilling out the PCV orifice, installing an oil catch can, and breather cap.

Same engine so it would translate to the STS.

04-16-13, 10:20 PM
The 3.6L has an oil level indicator but the only time it is sensed is at startup so it won't be coming and going on a rough road and the oil is sloshing around.

04-17-13, 09:50 AM
With this car, I've gotten into the habit of checking my oil regularly... about once every two weeks or before and after long trips, relatively speaking.

Interestingly, if I check it cold, it shows the oil right at the top (maybe a millimeter above) of the "cross hatches" on dip stick. If I start it, let it run for a few minutes, shut it down and let it sit for about 3 minutes, when I check it then, the oil is right at the bottom (maybe a millimeter above) of the cross hatches. Based on this variance I see in the oil level on the dip stick, I can understand how one might always be driving around on the lower side of "full". Particularly if they only check their oil level when the engine is cold.

04-17-13, 05:11 PM
The 3.6L has an oil level indicator but the only time it is sensed is at startup so it won't be coming and going on a rough road and the oil is sloshing around.

Only the n* got a level sensor. V6 does not have one.

04-21-13, 11:31 AM
I've had this exact same problem and was told it was my coil pack. They should be able to tell you which cylinder in misfiring but my understanding is just replace them all. Good luck

04-21-13, 01:09 PM
I wouldn't expect a warranty to replace a good coil pack.