Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Flickering Oil Light

'02 Hyundai Accent, 165K miles.

My route to work is six miles of secondary roads and city streets (25-40 mph), followed by 16 miles of interstate highway (65-70 mph), then another nine miles of secondary roads and city streets.

I have noticed only recently (last couple of weeks) that when I get to the end of the interstate leg in either direction, as I wait for the light at the end of the ramp, my oil light will flicker (sometimes very faintly) if I leave my foot on the clutch. If I get into neutral and release the clutch, the light stays off. It will do that at two more stops in rapid succession, but by the time I am at the last traffic light or stop sign of the trip, it has stopped flickering regardless whether the clutch is in or out.

Oil is recently changed and at proper level.

Any ideas?

Get the oil pressure checked with a calibrated mechanical gauge. I have a feeling the oil pressure is dropping due to a combination of wear and heated oil. The light goes on at 5-6 psi, and if the pressure drops to this at idle, this engine is probably getting to the end of it’s useful life. It will go on after the interstate trip most likely due to the slightly higher temperature of the oil at highway speeds.

Make sure the oil viscosity used w/the recent oil change is what is recommended by the owner’s manual. Newer cars are using low viscosity oil, but your may not be one of them, and you may have inadvertantly got too-low viscosity installed. Just a guess. But that could cause the probem observed.

Could also be a bad oil pressure sending unit or clogged/faulty oil filter.

Yes, try a new sending unit. 12 volts are not much electrical pressure to insure reliable electrical contact closure. It is surprising how well contact sensors without rub or wipe contact in a motor vehicle work as well as they do at such a low voltage.

Yes, a new O.P. sender switch and if problem is not resolved, move up a notch in oil viscosity, say from 5w-20 to 10W-30…Stop riding the clutch…

If this car has a temperature gauge see if it is going up more than it used to. Check the coolant level cold in the radiator, not the coolant tank.
The fact that the light goes out with normal driving means that the engine may go a lot more miles, after all, there is very little strain on an engine when it is idling.
Heavier oil just makes the symptom go away, not necessaraliy the problem.

1 Like

Since this is a recent event after an oil change I’d suspect the oil is thinning out too much. Other causes could be the motor idle speed is a bit too low. Lastly your oil pump could be getting tired. Assuming the oil pressure sensor is correct in turning on the light then a simple test might be to add about 1/2 qt of straight 30W oil. If the oil was changed with 0W-20 or 5W-20 it might simply be too thin for your older motor.

Like Others, I Have Seen A New (I’d Go OEM) Oil Pressure Sensor Fix This Problem, More Than Once Or Twice, On Vehicles Of About This Age And Mileage.

I bought an inexpensive gauge with a flex hose on it, years ago, just for checking pressure and pressure sensors. I haven’t used it in many years. You can either check pressure or just try a new sensor. You might as well go right for the sensor because I don’t think you are going to “repair” actual low pressure, anyhow, should that be the case.


If this just started right after the last oil change, I would start with that. First thing, have you checked your oil level? If it is low, then the oil will get much hotter than normal on the freeway portion of your drive causing it to thin out more than normal.

If the oil level is correct, then there is the possibility that the oil change place used the wrong oil, used one that is too thin for your engine. I’m pretty sure your engine calls for 5w30. I’m not sure where you are going to find a mechanic that has and knows how to use a viscosity cup.

There is the possibility that the oil filter is defective. The oil change place could just change the oil filter and add a little makeup oil to see if that cures the problem. If that doesn’t fix it, then have the oil changed again, using the proper weight of oil.

Then if you still have the problem, you can take a different route. You could just replace the sending unit, or have the oil pressure checked with a gauge, or simply move up to a higher viscosity oil like a 15w40. I think that I would want to confirm the low oil pressure before increasing the viscosity of the oil, either with a new oil pressure sending unit or a mechanical oil pressure test.

But start by checking your oil level.

“Oil is recently changed and at proper level.”

“Oil is recently changed and at proper level.”

That wasn’t my question, my question to the OP was, “have you checked your oil level?” with the operative word being “you”.

If everything else checks out, in high-mileage cars, especially those subjected to extended oil change intervals, the oil pump pick-up screen can become plugged up with coke and varnish, restricting oil flow…This requires removal of the oil pan to fix.

Certainly a good group of suggestions, thanks. I’ll let you know how it turns out.

I have a 2013 Ford transit connect. Oil light flickers like hell. Oil level is fine. Had a oil pressure test done came back good. Replaced oil sending unit. Light still flickering. Thinking it might be a electrical issue with the wiring harnest. Could there be a electrical issue that would make the right flicker?

did you replace the oil pressure switch because it was leaking?

If so, it can soak the wiring and you need to replace the pigtail

Yes I replaced it. Everything has been done. Everything is fine except oil light flickering