Hello, I have been searching the web and watching video's on low oil pressure light. I was thinking at first the light was coming on because the idle was to low (sit's around 800 rmp's) and being I can not adjust the idle.... ( or can I )...? I have flushed the oil with seafoam 2 times then ran it with mystery oil for a couple hundred miles and flushed it and only found a very little amount of crud. It comes on at low idle only it make no noise at top end like starving oil would make. I have tested the pvc system and that checks ok where as there is vacuum so I assume this means its working properly. I had to replace the axle on the passenger side and while removing the axle I struck the oil cooler a couple of times would that make the oil pressure light come on ? Could it just be a faulty oil pressure sensor? I work on all my car's, I put about 120 miles on daily which is all highway miles and don't want to damage the engine. Any input would be appreciated to try to fix this issue

 

You didn't mention year model - but common causes of low oil pressure (at idle?) is that there is debris in the pick up or the pump o-rings need to be replaced. Both can be serviced by dropping the oil pan, cleaning everything out and replacing the o-rings. Cause of a low idle speed or lumpy idle is usually intake air leaks - ie torn vacuum lines, cracked hoses in the air intake etc or a dirty intake/MAF. Fix those and your idle should go back to normal.

 

Does there exist any data for failed oil pressure sending units? The ones I've replaced were all leakers.

Every episode of flickering oil light can'r be from clogged pick-up screens, can they?

I'd consider draining the oil and adding 2 or 3 quarts of denatured alcohol to soak the pick-up. Then I'd drain it.
I know this isn't a fix for bad O rings or chronic sludge but the effect might be illuminating.

Does anyone know if sludge bits dissolve in alcohol?

 

It is possible for them to fail, but when you don't know what pressure it was set on to begin with, who's to say? It's obviously "working" at some pressure, so we can't really judge it. My bet would be low oil pressure for real, but low is a relative term. It may be that it comes on at 4 psi and you have 3.5.

It would be smart to pull the oil pan. I had one that had a bad pickup tube o-ring, and that really does not sound like this exactly. On that car, when the light came on at temperature X it stayed on.

On a car you really love, the immediate response to the light should be to put a gauge on. in this case it's working well enough that I don't think it's very mysterious.

 

Sorry I haven't been back I've been working a lot of hour. Back to the question on hand my volvo is a 2002 v70 base wagon it has 256,000 miles on the odom, but engine was replaced at 192,000. I had a chance this past sunday to do some needed work on the front end replacing the lower control arm's. While working on it I rechecked the pcv system and found the it is not working properly. I have pressure coming from the oil cap and smoke coming from the oil dip stick.Now would this make the oil pressure light flicker at idle? Would you still recommend dropping the oil pan? Will driving it like it is distress the engine ? I do all highway driving and the light does not come on while driving only at idle.

 

I have to repair the car in driveway and living in the northeast it's cold this time of year and not looking forward to doing the job, I would much rather wait till spring..Well I ended buying a new pcv system and ordered the seals for the oil pan just waiting for parts to arrive . I will replace the pcv system first and see if that correct's the low oil light. I'm hoping that it fixes the problem with out dropping the pan. If not gonna get cold

 

Well I just finished putting in the new pcv system and the car is smoking like crazy (blow by) oil coming from the exhaust pipe. Can someone help me out here why is this happening it never burnt any oil what so ever. Now if I take the oil cap or the dip stick while running the car stumbles and starts to stall. Did I do some thing wrong while installing it?

 

Well the car was running fine before I changed the pcv system so I am just going to put the old one back in. I did no see any cloggs in the block port's when I removed the old one so why is this happening....

 

Yeah so I just took it all apart again, put in the old system with the new hoses and after about 1/2 hour of idling it burnt off all that oil that spewed into the exhaust. Now things are back to normal but I still se oil pressure light when warm so I am going to drop the pan and put in new seal's and gasket's ....... KEEPING FINGERS CROSSED.....