My oil light came on a couple weeks ago. I had hoped it was the oil pressure switch, so first thing I did was swap it with a new one...no luck. I just got finished dropping the oil pan to check the pick-up tube. It was quite clean although there was a bit of "sludge" in the bottom of the pan that I cleaned out. Got it back together, and the light is still on.
What would be the next step? Oil pump? What do I need to look for to find out if the pump is the issue?
It's a 3.9. Not sure how it's driven actually, but it's a 1993.
It will be a distributor driven pump. It is a high volume pump that relies on thicker oil. What oil are you running? Is the light on all the time or only at idle?
It will be a distributor driven pump. It is a high volume pump that relies on thicker oil. What oil are you running? Is the light on all the time or only at idle?
I filled it with 5w40 synthetic after I was done with the oil pan. I've only had it a couple months, and don't know what was in it before. The light comes on and stays on at start-up. It does not seem to be affected by rpms. I think I overfilled it a bit though, not sure how that would affect it but I will be adjusting it to the proper level tomorrow. Before I did the oil pan the light would usually act like it does now, but it would sometimes go off randomly. When I drove from my apartment to my parents house to work on it it went off when I was at a light and didn't come back on the entire drive.
I would not anything below 15W in those older oil pumps. The most common issue that may cause this is a stuck pressure relief valve. On the bottom of the oil pump you will find a bolt with a large head. Behind this bolt is a spring and the pressure relief valve. When you undo the bolt the spring should fall out and the valve (a small piston) should come out easily. If it doesn't it is most likely sticking open. So you will need to get it out and probably best to buy a new piston.
So i pulled the oil pump. Replaced the pressure release valve assembly as well as some of the other plugs and washers that came with the kit. The upper gear fell out when I pulled the cover, but I could not get the lower gear to come out more than a half inch or so. Packed it full of petroleum jelly and put it back together...light is still on.
Edit: When I pulled the oil pan, I broke the oil level sensor so I have left it disconnected. Leaving the oil level sensor disconnected should not cause the oil light to come on, correct?
Edit: When I pulled the oil pan, I broke the oil level sensor so I have left it disconnected. Leaving the oil level sensor disconnected should not cause the oil light to come on, correct?
That is your answer. It is the same warning light for both low oil and low oil pressure.
There should have been two wires going to the oil level sensor (color coded white with black stripe. If you left the two ends disconnected, try connecting the ends together to see if it fixes the problem. The level sensor goes to a little ECU that then sets off the oil light. I am not sure what the ECU is expecting from the sensor. If joining or disconnecting (the opposite to what you have done) does not fix the problem, you will need to find the ECU and disconnect it.
The simple fact that is unplugged will only cause it to flash at startup as if it was actually low.
But, if the low oil level logic unit has failed that will cause the light to stay on. My sensor has never been attached and just recently the logic unit failed causing the same problem. I just unplugged it... problem solved.
I would test the pressure sender unit first. Disconnect it then hook up a test light between it & the positive battery. Light should be on. Start the rover & it should go out in a second or two.
The light acts the same as it did before I broke the level sensor, comes on and stays on, doesn't flash. Though I agree it would be a good idea to get the pressure checked with a gauge, I'm not equipped for this. I'm not driving it so not too concerned with causing damage. When I have started it for short periods it seems to run smoothly except that it seems the belts have become quite squeaky...I'm guessing from using PB blaster to loosen bolts and carb cleaner to clean off the old gasket.
Ok! So I disconnected the oil level logic unit...light is off! It came on like normal when I started it and then when off after a few seconds. Just to confirm, the logic unit has zero effect on weather or not the light comes on due to low oil pressure, right?
Ok! So I disconnected the oil level logic unit...light is off! It came on like normal when I started it and then when off after a few seconds. Just to confirm, the logic unit has zero effect on weather or not the light comes on due to low oil pressure, right?
If you want to make sure, just earth out the wire to the oil warning light at the low pressure sender. If the light comes on it should still work as normal.
It will be a distributor driven pump. It is a high volume pump that relies on thicker oil. What oil are you running? Is the light on all the time or only at idle?
So I have a 90' RRC that runs great but has the nagging Oil Light on. It does go off at higher RPMs and only comes on occasionally. Any suggestions or ideas?
Thanks
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Oil pressure issue
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