I have a 2004 Chrystler Concorde with only 68,000 miles on it. Last year around this time, the oil light began to flicker and our mechanic replaced the oil pressure sensor. Fast forward to last month and the flickering light returned. I narrowed it down to the following: It takes about 20 mins of driving for the problem to show itself, and then it only does when I am decelerating to less than 1 RPM, such as slowing to a stop at an intersection, and often around 5MPH or less. The moment I take my foot off the brake, though, and begin to ever so slightly accelerate, the light turns off. This time I took it to my nearby Chrystler dealer who says the oil light is a common issue with Concordes. They replaced the sensor and claimed it fixed, unaware that they need to drive it for about 20 mins to see if it is truly fixed or not. Its not, which means its not the sensor. They said the oil pump (?) looks good. Any thoughts on what else it could be and if its a real problem or not? Thanks!
(Worth noting: recently the car failed to switch gears on an incline causing the engine light to come on. The dealer repaired the transmission. I’m inclined to think this oil light issue is not related, but what do I know?)
68,000 miles on a 10 year old car suggest to me all city driving. With a city car, it’s difficult to relate miles driven to wear. A city car can have as many hours of operation on it as a car in my are with less that half the miles. In short, 68,000 miles on a city car can take as many hours to accumulate as 250,000 miles in my area.
I suspect that you’re dealing with normal engine wear. Oil pressure is developed as the pump pushes the oil through tiny spaces between the bearings and the wear surfaces. As the surfaces wear, the oil flows through more easily and the oil pump has difficulty maintaining pressure, sort of analogous to trying to keep a balloon inflated that has a pinhole in it. If you don’t make a habit of checking your oil regularly, if you run low occasionally, and/or if you rarely change your oil, that exacerbates the problem, accelerating the wear.
As the engine warms the oil, in your case apparently 20 minutes of driving (not abnormal at city speeds), the oil becomes thinner, flowing more easily through the spaces and making it more difficult for the pump to maintain pressure. As you accelerate the engine, the pump spins faster and produces more pressure, elevating it enough to shut the light off.
I’d start by putting a “T” fitting on the oil sensor hole with a separate mechanical gage to see how low the oil pressure is actually getting. If it is getting too low, you may want to try a higher base-weight oil. Some might change the oil pump, but oil pumps are actually very basic interlocking gear-like impellers that spend their lives awash in fresh oil, and they really don’t generally wear out.
+1 for the same mountainbike. What weight oil are you currently using? You might be able to go up one weight if you check your owner’s manual. That usually helps with this problem.
the same mountainbike,
WOW! This was my first post here and I am so grateful for your response. Thank you for being so detailed and generous with your time. The car uses the lowest weight oil. It sounds like going up one grade is the next step. I’ll post back soon. Thanks again!
If you are using the lowest weight oil ( 5w-20 ) or (0-w20 ) your owners manual states to use 5w-30 ! It could be the 20w is thinning out when it gets hot. This 20w oil is not meant for all cars, stick that in my 74 Nova and wearing of the bearings will begin due to tolerances. You could even try a 10w 30 if your bearings are worn…What do you have to loose ? We used 10w-30 for years before this 20w stuff came out for newer cars.
A fairly common problem with newer cars. The manufacturers try to squeeze every bit of mpg out of the engine and one way they do it is recommending low viscosity oil. Ok at first, when the engine is new, but as parts wear the oil pressure is the first to take the hit. There are also some reports of substandard machining observed in car engines these days, right from the factory, and that can eventually cause low oil pressure.
It’s also possible the problem is something to do with the oil pressure regulation system. On some engines it isn’t that big of a deal to remove the oil pan and do a look-see at those oil-pressure regulating parts, valves and springs & such, looking for something wrong.