I have a 2007 Sebring Limited with the 3.5L. At idle, the oil light and chime comes on sporadically. But when I take off, or when the RPM goes above ~700, it goes away. I don't hear any noticeable noise coming from the engine, and the oil level is fine. I was a quart low a few days ago so I added some, and it's been doing it ever since.

Did I maybe add too much, and it's creating a low pressure situation, at least for those milliseconds?

Or would it be the oil pressure sending unit? I've had a MIL for "Oil pressure sensor voltage too high" a few times before, but I cleared it and it went away.

Like I said, there are no performance or noise issues whatsoever. The engine sounds fine. I do plan to get an oil change at some point, however.

 

"I do plan to get an oil change at some point, however."

I certainly hope so! Oil change intervals are a subject of some disagreement. The people that make money changing oil think you should do it every other week. The car manufacturers suggest 5,000 or 7,500 miles, even up to 10,000. Some people claim that with full synthetic oil, you never need to change it, just change the filter periodically and otherwise keep the level up.

As for your oil light, there was a known problem with the oil pressure switch on the 2.7L engines. I wouldn't be surprised that the 3.5 might have it too. Try replacing the switch before doing anything else more drastic. When you pull the old switch, make sure the passage leading to it is clear.

 

The oil was changed shortly before I bought it, which was a few weeks ago, but it's already dark brown, so I'm going to have it changed with full synthetic here shortly.

Would anyone have access to a FSM for our cars? I've seen them on eBay but they're around $120 which is ridiculous in my opinion. Would anyone know where the oil pressure switch/sending unit is located on the 3.5?

 

My 2.7L was doing the same thing. As has been mentioned, the oil pressure switch are suspected culprits.
I say suspected because after changing my oil to a synthetic (PAO) my son took it on a highway trip (about 650km) and it has never flickered since (about a year and a half later).
I wonder if changing the switch helps clear out some "gunk" in the oil passage and so the new switch then registers properly.

Perhaps a good flush and a change with a quality synthetic will give you similar results. Sure won't hurt things and fairly simple to do.

I know that some people claim that you never need to change a full synthetic.... but show me a manufacture of synthetics that makes that claim. I've been using them for 30 years and have never seen such a claim.

Anyway, I digress and back to the topic... if you don't see an improvement (i.e. light still flickers) after your flush & change to synthetic and a tank or two of fuel later.... time to change the pressure switch.

 

Not sure if this may apply to you particular concern but may resolve someone elses,

TSB: 18-003-09 REV. C

SUBJECT:
Flash: Driveability Improvements Or MIL Illumination Diagnostic Trouble Code P0452 -
Evap Pressure Switch Stuck Closed

OVERVIEW:
This bulletin involves selectively erasing and reprogramming the Powertrain Control
Module (PCM) with new software.

MODELS:
2008 - 2009 (RT) Town & Country/Voyager/Caravan (Includes International Markets)
NOTE: This bulletin applies to:

2007, 2008 JS vehicles equipped with a 2.4L Engine and Automatic Transmission
(Sales Code EDG or ED3 with DFF) built before June 19, 2008

2007, 2008 and 2009 JS vehicles equipped with a 2.7L and 3.5L engine (sales code
EER or EGF) built Before October 15, 2008

SYMPTOM/CONDITION:
Some customers may complain that the engine stumbles, runs rough, has idle fluctuations and/or surges at idle or there is a MIL illumination. Further investigation by the technician may find DTC:
- P0452 - Evap Pressure Switch Stuck Closed

Module, Powertrain Control (PCM) - Reprogram (B) (0.2 Hrs.of labor time)

 

That has absolutely nothing to do with my problem.

 

I hope the switch does it for you. It didn't for me. I put the switch in, a new oil pump, finally ended up replacing rod and main bearings (with the motor in the car) except for the rear main bearing. This fixed it and it runs great. On a scale of pain in the but 1-10 I'd say about a 8.

 

I found out it was the oil pressure sending unit. It was leaking and it leaked onto my belt and it slipped off and got torn to shreds. $670 later, no issue.

 

Besides; the idle rpm is 650; usually when it goes under 650 it has also something to do with that the air filter hasn't been changed/ spark plugs are down as well or the upper manifold might leak. Just to mention it in case the oil pressure sensor is fine.

Since the sensors are the same at the 2.7 and 3.5 engine, it is always worth a look after about 65,000 mileage.

 

Oil pressure sensor was fried and was leaking oil onto the belt, as I said in my previous post.