Oil Pressure Light is on at the cold start


#1

The oil light on my 2005 Chryler Town & Country comes on when started when it is cold outside. It stays on until I turn the key off and restart, then it goes out and does not come back on. My mechanic cannot find anything wrong. This only happens in cold weather, not in the summer. Any ideas?
Mountain mama has posted the same question, but there is no conclusion. I now have the exact same problem, same car.

Thanks for the help
tc_chrysler


#2

If your mechanic has an oil pressure gauge and whatever adapters may be needed, s/he can hook it up and measure actual oil pressure upon cold startup. If the pressure is OK, then the problem is most likely that the car’s oil pressure sensor is unreliable. This part is usually pretty inexpensive and it may be simpler and cheaper to just unscrew the original one, screw in a new one and attach its wire.

If actual oil pressure is too low and stays too low, more extensive engine diagnosis is called for.

Is oil level OK? First things first…


#3

Some oil filters have backflow preventers. Some times an older filter gets superceded by a new number. Try an oem or older filter number and see if the problem persists.


#4

Also make sure you are using the correct weight of oil. Sometimes you need a different weight oil for winter than summer.


#5

Have your mechanic disconnect the oil pressure switch wire at the engine. On the next cold start see if the light comes on. If so I would suspect a problem with the lamp check circuit and maybe the part of the ignition switch that activates the lamp check.

Leave the oil pressure light wire disconnected only long enough to isolate the problem. You don’t want to burn up an engine for lack of warning.


#6

You may be on to something. Could be just normal operation at start up.


#7

I think OP already understands this, but it could be that the engine is just plumb worn out. The clearances in the oil channels increase enough that oil pressure cannot be maintained. And it usually shows up on cold starts.

If the car has a lot of miles on it or routine maintenance has been deferred, that’s a likely explanation. OP, I can’t speak to this specific make/model/year, but you know that Chrysler products in general tend to be near the bottom of the Consumer Report’s reliability list, right?


#8

There is a bulletin (TSB 08-052-05 REV A) that applies to early build 2006 Caravan/Town & country. This may apply to your vehicle if it is close to the production date or if the engine has been replaced. The problem is with a poor ground of the oil filter adapter causing the oil pressure light to illuminate. This is caused by the anti corrosion coating on the oil filter adapter bolts. The correction is to replace one of the (black) plated bolts with a common (zinc) plated bolt.


#9

There have been several Chrysler cars in my family that have displayed this behavior. Oil pressure is HIGHEST at cold start, it does not increase as it warms up.

The problem on our cars has always been fixed by a new oil pressure switch.

The key clue was that turning off the ignition and restarting the car always made the light go off, at least until the next cold restart.


#10

update:
only changed oil and oil filter just to isolate the issue with the oil pressure sensor. Still the same problem. The car has 122450 miles, but it runs very smoothly. It burns a quart of oil every roughly 1000 miles. In my next oil change, I will replace the oil pressure sensor as oldtimer11 suggested.


#11

To Shanonia: The oil level is OK. Do I need to drain the oil before I can unscrew the OP sensor?


#12

To Bing: The light stays on until I turn the engine off and then turn it back on. That can’t be normal operation and it started about a month ago when the weather is getting colder. The viscosity of the oil is what Chrysler recommended.


#13

To GeorgeSanJose: I hope my engine is not at the end of its life yet. I plan to run another 20k to 30k. Maybe it’s just my wishful thinking.


#14

To researcher: Then I have to leave my car at the repair shop which I can’t do.


#15

To Nevada_545: Probably not related to that because if it is, the light will stay on no matter cold or warm start.


#16

No need to drain oil before unscrewing the OP sender. Replacing it is a simple job, not nearly as involved or potentially messy as changing oil and filter can be. The sender on your engine is probably facing the front of the vehicle, near the oil filter, therefore easy to get to.

allpar.com is a fine site devoted to Chrysler vehicles, very helpful if you have vehicle-specific questions.