Hello, recently i've had a problem with my 93 camry. I had a mechanical oil pressure gauge installed and was monitoring my oil pressure when I first started my vehicle. It started up, shot up to 80PSI. Every time i'de slightly touch the throttle, it would jump up to 100 (I am assuming it goes over 100Psi because its only a 100Psi oil gauge and it was pegged out). I shut the car down immediately. I waited a minute, re-started it and it was at 75Psi. I tapped the throttle again and this time it jumped up, then went down to 2Psi. My oil pressure light turned on at this time. I pulled the pan to inspect the Main and Rod bearings and they feel tight to the touch (No abnormal sounds). I removed the pressure relief Valve on the oil pump, and noticed the plunger was stuck at the top of the cylinder. The inside of the cylinder was a brown varnished looking color. I tried to remove the plunger valve, but I couldn't get it to drop out. I cleaned the brown varnish out so it was silver again, and re-installed the spring. I re-installed the oil pan and started it up. Same thing. Stuck at 2Psi. Once Warm, if I give it gas to 3000 RPM, it goes to 25-30PSi. The throttle goes in sync with the oil pressure gauge. If it Rev it from 2000 to 3000, the needle goes along with the RPM. I know that as the motor increases in RPM, the oil pressure gauge will increase too, this doesn't rise the same as it used to. Its instantaneous with the Throttle. From what I've read, a relief valve stuck all the way up will cause very high oil pressure. Is it possible that the relief valve could have been stuck all the way up for some reason, then when the RPM spiked to 100+ PSi, it partially opened the valve making it stick partially open all the time not allowing any pressure to move?
The motor does not have any sludge. When I first put the motor in (Bought the vehicle with a spun bearing) it had a minor sludge issue. None in the oil pan, but a very little in the valve cover. I did oil changes every 1000 miles to resolve this issue.
I did not remove the bearings and check the clearances with plastigage yet, because this is my last resort.
Do Bearings really just all of a sudden loose oil pressure? I thought that bearings would gradually wear out, causing the pressure to gradually go down little by little until they need replaced.
Also, if you simply would like to replace engine bearings if there is not a huge oil pressure problem. Instead of running plastigage, can you install Standard bearings and be OK? Or does the crank wear out with the bearings, leading to having to resurface the crankshaft?
The motor I installed had 102,000 miles on the odometer. I've put about 10,000 miles on it since the install.
Done the following in the 10,000 miles:
Transmission shift solenoids / Valve body
Distributor Cap, rotor, Coil, Pickup
Spark Plugs, wires
All Vacuum lines
Throttle Body cleaning
Timing idler pulley
Oil pump gasket and O-Ring
Numerous oil changes
Brakes All around
Rear Main Seal
Differential Drain / Refill
Axles (both sides)
Strut tower bushings
Control Arm Bushings
Sway bar bushings
Brake fluid change
rear Wheel bearings
Front wheel bearings
inner/outer tie rods
Rebuilt P/S pump
Rebuilt P/S Rack
Valve cover Gasket
Spark Plug Tubes
Oil Pan Gasket
Coolant Bypass O-Rings
theres more but I cannot think of anything.
If you guys have any incite onto my low oil pressure problem, I would greatly appreciate it. I've posted some questions on an online forum for toyotas, but they aren't that knowledgeable when it comes to oil pressure issues. I've read on a seach that No oil pressure indicates bad oil pump, low oil pressure indicates bad bearings. I am hoping that the bearings are not bad, but like I said this happened in such a quick amount of time that I find it hard to believe the bearings just "went bad".
You've been busy! I don't think varnish in the pressure relief valve is the problem. 100 psi is going to make that baby move. I would suspect debris blocking the port. Does the oil filter look like it's ready to explode? Based on the multiple different symptoms, you might look for a broken spring in the pressure relief valve. As for replacing the bearings, I did that on the Mitsubishi engine in my Grand Caravan in a misguided attempt at solving a knocking noise, (which is still there ten years later). If there is no wear on the journals, new bearings should work fine. They are very soft and the journals are hardened so the bearing is what will wear. If they are really the cause of low oil pressure though you should see the bearing worn into the next layer of metal which will usually be copper-colored. If you find that, look real close at the journal before just popping new bearings in. Same with the rod bearings. You mentioned an oil pump gasket. What led you to that? Are you referring to a gasket between the pump and block? Don't believe I've ever seen one there because oil would just drip back into the pan. Any chance it's mispositioned and blocking the passage?
March, 18, 2011 AT 2:56 PM
Well, I pulled the oil pump gasket was leaking so I wanted to replace it. There is an oil pump gear to the left of the harmonic balancer shaft. The oil pump is held on by 8 - 10 (10mm head) bolts. I removed the belt, bolts and installed a new gasket on it.
The oil filter looks fine, its not swelled or leaking. I tried to access the Oil Filter pressure relief valve, but I couldn't remove it from the block. (On the 5s-fe there are two relief valves.) I could physically put a screw driver inside where the oil comes out and feel something hard that had spring tension, but I am not sure if its broken or not.
You don't think a partially stuck open pressure relief valve on the oil pump would cause my problems?
March, 18, 2011 AT 7:32 PM
It would be worth looking into but I would suspect a broken spring, not varnish or debris. Varnish is more likely to be a problem in the valve body of an automatic transmission, not in engine oil. Also, the oil pressure relief valve is constantly vibrating back and forth and will scrape the bore clean. About your comment earlier about bearings failing suddenly, that is entirely possible. Gradual wear over time is more common and will cause the low oil pressure we're familiar with, but they can fail also when a piece breaks off and goes around with the crankshaft and scoops out more bearing material with each revolution. The clue there is you will see the oil pressure bounce up once per revolution as the connecting rod or crankshaft journal is hammered on by the piston and momentarily blocks the oil feed hole to that journal. You should hear the knocking too. If you don't see or hear those clues, the bearings would probably be the last suspects.
March, 18, 2011 AT 8:16 PM
Okay. Well I do not hear any sounds coming from the motor so I am assuming that the crankshaft bearings and rod bearings are last on the list to check. I had completely removed the Oil Pump Retaining clip, Washer, and Spring. In the manual, it says the Plunger should fall under its own pressure. It does not. I am going to be replacing the oil pump with a new one (in the mail).
How would I go about checking for a broken spring, or blocked oil passage? Thanks for the advice so far.
March, 18, 2011 AT 8:51 PM
You'll just have to pull it apart. Even with a broken spring you might not be able to move the valve easily by hand.
March, 18, 2011 AT 9:07 PM
So there is a spring above the plunger as well? Just trying to get an idea of how its put together.
March, 18, 2011 AT 9:33 PM
Yup, that's what sets the pressure. Sorry I don't have access to a picture.
March, 18, 2011 AT 9:42 PM
From what I can see from the Diagrams I have it goes in this order on the oil pump ; 1. Snap Ring 2. Retainer 3. Spring 4. Relief Valve. It doesn't list another spring on top of it. What I was saying was my manual says that the relief valve should drop down under its own pressure. When I remove 1, 2 and 3 the valve should drop. It doesn't. It seems jammed at the top of the oil pump.
March, 18, 2011 AT 10:42 PM
I'm sorry. In my mind I was looking at the parts in the same location but in the opposite order. I started with the valve and the spring "behind" it as the oil would see it. Your manual is showing it in the order the parts come out and go in. You're right though, that valve should just slide out. How did the spring look? Can you tug the valve out and look for what caused it to stick?
March, 18, 2011 AT 11:05 PM
Yeah I tried to use some Needle nose pliers and Spread them out to compress on the inside of the cylinder, but it wouldn't budge at all. I think the only way to get it out is to remove the pump housing completely and use a screw driver or punch and go in from the back side (Towards the motor). The spring looked fine though. Had a good amount of tension, no cracks of missing pieces.