My 89 Plymouth Sundance runs very well when it gets warmed up even tho it has 225K miles on it. Lately, when sitting at a light or idling, the oil light comes on. We changed the oil and filter but that did not help. What should we do next? Thanks
You could be quite low on oil, but you said you just changed oil & filt. So I would think either your oil light sensor is failing or at that mileage your oil pump is getting tired. I don’t know what the climate is were you live ,but if it is quite warm ,change to a much heavier oil & see if that keeps the light from coming on.
It is probably die to low oil pressure at idle. Worn bearings etc. could be the cause. How often did you change the oil during the life of the car? Next you could take it to a reputable mechanic and have them check the oil pressure, but with your remark that it runs very well when warmed up leads me to question does it run well when cold? Do you have a tach and what is the rpm at idle when the light goes on? It could be in need of basic maintenance, plugs filters, or even fouled injectors etc. if it idles too low that could cause the pressure warning light also
Replace the oil pressure sender. It’s cheap, and it may solve the problem.
If replacing the sender doesn’t make any difference, then you may have a more serious problem within your vehicle’s engine.
At 225k miles it could be worn crankshaft bearings. Pray that it’s the oil pressure sender.
Have the oil pressure checked with a mechanical gauge when the engine is warmed up. If it’s low, you probably have worn bearings in the engine. If the engine isn’t making any mechanical noise (and the pressure is indeed low), you might get more life out of it by switching to a little heavier weight oil.
I would also make sure that the idle is not too low. I would check for any stored codes in the OBD1. Possible defective IAC (Idle Air Control) could cause low idle.