Oil light comes on only at idle and only when thr engine is hot. it goes fine at start up and only comes on after about 10 miles and only at idle. the oil level is correct and it is the correct oil

if your saying that your low oil pressure light is coming on (or flickering) at engine idle , but goes out when engine is above idle (going along) this is sure sign you have a problem in your engines oil pressure system :
serious !~


some common reasons for this to occur are:

worn out engine parts allowing oil to leak out and not lube parts properly (hi engine miles)

low oil level -not enough oil inside engine to get pumped around proper


restriction in oil system - blockage in oil passageways even oil filter will count (hi miles)

1. As a basic measure I would make sure the correct grade and spec oil is going in the engine. You can no longer trust that a local mechanic or even a dealer service center will necessarily use the required product as stipulated by the manufacturer. It is always better to buy and supply your own so you know the correct product is being used.

2. I would not assume there is a problem with the oil pressure warning light even though there could be.
The first thing the mechanic should have done when you reported the oil pressure issue is to hook up an independent mechanical oil pressure gauge and check oil pressure when the engine is hot at different RPMs. Any oil pressure issue will usually show up at idle when the engine has been warmed up properly and the engine oil is hot (unless you have some kind of intermittent oil pressure relief valve that is sticking). Just replacing parts without actually knowing what the oil pressures are at different RPMs is being sloppy and negligent.
This is what you need to do now. Contact a business that can hook up their own pressure gauge to your engine and have them check the oil pressure readings at various RPMs when the engine is fully warm. If there is a low oil pressure issue it will show up on the oil pressure gauge. As you have a new oil pump there should be no issue now with oil volume or a sticking oil pressure relief valve which on your engine should be part of the oil pump assembly.

3. Worn engines will not be able to sustain required oil pressures. Oil pressure is not produced by the oil pump. The oil pump produces oil flow but the resistance to flow is what produces the oil pressure and that resistance is created by fine clearances between operating engine parts especially on the crankshaft and components connected to it. Once the engine wears the clearances increase and the oil flows past the parts much more easily and produces/builds much less pressure.
How well your engine with over 90000 miles has been maintained depends on how often all the owners changed the engine oil and filter , whether they kept the engine oil level up to full (most owners rarely ever check oil levels between services) and whether they always used the correct product. Manufacturer oil change intervals shown in service schedules can be 10000, 12000 miles or more which is much too infrequent for the type of use 95% of private vehicles experience which typically are on the severe to very severe use end of the spectrum. Engine oil typically needs to be changed at least at half the mileage shown in service books (at least twice as frequently) and thus at least every 5000 miles if you want your engine to last.

Clean the throttle body inside and the idle air control motor.This will help.

It's possible that when the engine is at idle RPM it may not produce enough pressure causing the oil pressure sender to activate the light. Does it do this when you just sit and idle the motor? You may also have a oil sender that may need to be replaced.

1st thing to try is to replace the oil sinding unit, if the problem percets then have someone install a manuel oil pressuer gauge to check the oil pressuer at hot idle if oil pressuer is less then 10 psi at hot idle then replace the oil pump.

You can't trust the light sensor, so you need to get a mechanical gauge. A cheap capillary tube one is only $10.
You should also change oil.
If the engine has over 100,000 miles, you could consider 20W-50 oil.
You could also have a problem with fuel or ignition, causing oil dillution.
Does it look too thin or smell like gas?
It could also be the oil pump is bad, but that is not normally worth trying.
The number of miles on the engine would help.
But low idle oil pressure is not that important.

its a high mileage engine.
all you need to do is use a thicker oil and the light will go out at idle speeds.

use a 50w sae valvoline racing oil.
plus stp oil treatment.

do that and that light is all gone.

bad to worn out oil pump or excessive oil passage clearances that allowing more oil to pass thru them at a lower pressure due to the bigger opening. It can be a sign of an emminant engine failure due to oil starvation.

have the engine wire harness checked maybe a communication problem between modules.

I had the same problem with my 2003 Lancer OZ. The oil level and pressure were ok. Car was fine with no light when starting. After 10 to 15 mins of driving it would come on when I was stopped. It would go away when I pressed accelerator. Try replacing the Oil Sending Unit. It's about $10 and easy to swap. That was my problem.