Need Help !!!!
Have a Camry 2001 2.2 and just changed the timing belt, Cam/Crank Seal and Oil pump gaskets since it was leaking oil from Oil Pump. After driving approx. 20 miles it is showing low oil pressure light. What could have gone wrong?

Thought Oil pressure sending unit may be bad, swapped the unit from another camry (same year) and the other car does not have the oil pressure problem. SO the oil pressure sending unit is not bad.

 

Make sure the oil check light system is working. The light will come on when the pressure is below 4.3 psi.

Did you install a new preformed O-ring between the pump assy and housing behind it and make sure the O-ring was not damaged when the pump assy was installed. This prevents air leaks.

Were the dots on the face of both driven and drive oil pump gear were facing in the same direction?

The pump may have lost prime. Some owners pack grease or petroleum jelly between the gear faces and housing.

However driving with low oil pressure for 20 miles should have caused engine problems.

Suggest first checking actual oil pressure at the sender by installing a a gauge. Normal oil pressure warm is around 36-70 psi at 3000 rpm.

Instead of starting the engine you could remove the spark plugs to allow the engine turn over with less resistance and crank engine to determine if oil pressure increased.

If no oil pressure might over fill the engine oil pan to raise the level of oil in the intake tube going to the pump.

Or force oil back through the oil filter threaded port via compressed air or a hand pump. The goal is to get oil into the oil pump gear housing.

The oil pump picks up oil from the pan, pushes it through a pressure relieve valve to the oil filter.

 

Yes, I did change the o-ring with a new one. I also checked that the dots inside the oil pump facing same direction.
I did not drive with low oil pressure light on. After the timing belt/seal change I drove around 20 miles with no issue and after that the low oil pressure light started showing. Initially flickering and they full light. I stopped driving after that. Now I can start the car and run for around 5 miles with no low oil light and then it will start showing the light.

 

Normally oil pumps don't wear out as they are always lubed, Toyota does have specs for clearances between the gears and housing thus inspection is possible.

Highly suggest installing a pressure gauge where the pressure sensor installed and check actual pressures. Pressure will vary with oil temperature and engine RPM

With engine oil warm pressure should be 4.3 psi or greater.
At 3000 RPM 43-78 PSI.

Determine what the pressure is doing. If the oil is cold it should rise higher then normal then lower as the oil heats up. But not be below 4.3 PSI at idle.

Check real oil pressure, if a problem the cause could be one or more below.

Stuck open oil pump bypass valve. This valve prevents pressure from getting too high. The valve is built into the same cover the oil pump bolts up to. Access to the valve requires removing the oil pan.

Plugged oil intake screen in oil pan.

Oil filter problem. The filter should have a bypass valve but who knows. You can try a new filter.

Oil sludging of engine. You can check for sludge removing the valve cover and looking at the valve train for built up. The sludge get into the oil passages and also plugs up the oil intake screen.

Worn out engine bearings-excessive clearance causing leakage.

Worn out pump assy.

Find out what the pressure is doing and post back. Obviously don't operate the engine with low oil pressure.

Why the problem started now can only guess.

 

Thanks Joey for your insight into the possible problems. I dropped the oil pan and find that the oil intake screen is plugged with sludge. Cleaned the screen and the gasket which connects the oil screen to the oil pump is a thin metal piece. Should I use the same gasket or use a new one. If using a new or old one, what kind of sealant to be used with the gasket. Also for oil pan should I use the after market gasket or use some rtv sillicon gasket maker and which one you recommend. Also for the sludge problem what is recommended. Thanks.

 

The screen assy can be cleaned and reused. Use a new gasket as it might be a crush type design, meaning single use. If the gasket does not seal, air could get into the plumbing and cause the oil pump to lose prime. Torque bolts and nuts to 48 INCH lbs.

Toyota uses their own brand of form in place.

Suggest something like Permatex® Ultra Black® Maximum Oil Resistance RTV Silicone Gasket Maker. Auto parts stores would have and sometimes the auto section of the department stores.

Very important to follow the directions on the tube for curing time. Don't add engine oil (and start engine) until the cure time has passed which may be 24 hours. Otherwise you might have a leak.

Pan bolt and nut torque is 48 INCH lbs. Don't over torque or you can squeeze out all the sealant.

If you don't want to use a gasket sealer on the pan auto parts store seal a normal gasket.

Might change the oil filter.

As to sludge, depends on the extent of the problem. Suggest removing the valve cover an taking a look at the valve train for sludge. The link below has photos of sludge on the valve train.

5SFE sludge - Bing Images

Plus use a flashlight to look up into the crank area for signs of sludge.

Don't confuse sludge with minor varnish built up that is a VERY thin brown coating.

If the engine has a lot of sludge the cleaning process is difficult. Some owners run solvent through the engine. See link below:

Myth or Fact? Gen-4 Sludge problems? - Toyota Nation Forum : Toyota Car and Truck Forums

But before getting to this point check the valve train and crank area for sludge to determine the extent of problem.

Could be just debris on the oil intake.

When fixed suggest changing the oil and filter more often, say 3000 miles. Plus cut open the old filters and look for debris.

Sludge is caused by hot engine oil, water in oil, hot spots on engine metal, failure to change oil sooner enough, poor venting of engine (check PVC system for proper operation and valve and hose are not plugged).