oil oil pressure problem : Help please

[colin.braiding@jcu.edu.au]

A little help please? I have a Corolla Ascent 2007 and the oil light keeps coming on. over the past few weeks I have changed the fuel filter, oil. pressure switch, tested with a mechanical oil pressure tester ( pressure briefly okay and then drops after a minute) ran diesel to flush the engine, cleaned out the oil pan and oil pump pick up screen thoroughly, dismantled and cleaned the valve cover, replaced the oil screen filter under the cam cap, tested and checked al the VVT components, cleaned all the oil valves and other components, removed sludge, unblocked oil passage channels , put new gaskets and O ring in the VVT gear in the valve cover. What else is there guys? The car is older but has never been thrashed or overworked. It did have a fair bit of sludge in the valve cover and I got most of it much cleaner than it was. Do the Oil Pumps go often in this model? Is the engine just worn out and the bearings and other parts just not providing the resistance to bring up the pressure? I am stumped at this point and have gone through the Haynes workshop manual suggestions. I have reviewed some online suggestions but feel that I should check in with you guys for help. suggestions please..

[neural revolt]

What do you mean by often? How many k's on the clock? And when was the pump changed last time if at all?

Your only hope is that the pump is gone. If that's not it, you don't have any other hope, the engine is worn out.

You don't need to thrash the car to kill the engine. Just drive a few km when it's low on oil or some such and your bearings are toast. Lots of sludge would suggest some neglect in oil changes, possibly running the engine low on oil. Changing oil on time and with the correct one should keep internals clean even in high mileage cars.

Also, you need high oil pressure at low RPM, not at high RPM. Load factors into it as well, but generally speaking if you chug it along at low revs you are more likely to wear the bearings (and glaze the cylinder bores) because you don't have enough oil pressure to keep the rotating parts away from their bearings or in the case of the pistons to expand the rings and properly push them into the bore. I have a high mileage 2005 car but the previous owner lived in the country and did long trips to work and back, not a few k's with a cold engine in start stop traffic and then stop like city cars. The result is the engine pulls like a train. We are killing it now with short trips to shopping and such but when I have a chance I boot it up the freeway as much as I can.

When you measured the pressure with the mechanical gauge, was the oil (engine) up to temperature? If it holds pressure when the oil is cold and then it is losing it I would say the pump is good and the engine is gone.

Edited March 6, 2020 by neural revolt

[colin.braiding@jcu.edu.au]

Thanks for your reply Neural revolt, it is at 178000K.  It has not had a replacement oil pump previously. It holds pressure until it is warmed up and then drops very low.I appreciate you taking the time. I think your last comment hit the case and point. The bearings are probably worn and the engine cant hold the resistance to the flow to maintain pressure.

 

[neural revolt]

Yeah, somebody probably drove it low on oil or something like that and killed the bearings.

How much is it to change the oil pump? If it's not too much I would try a last ditch effort and see.