Lost oil pressure.

[csj]

Hello everybody, I am a new member to this forum, but have been reading here for some years and have found lots of helpful info here. I have a 96 LC that I have owned for a few years. 212k on the odometer. A couple of weeks ago I started intermediately losing power steering when turning into a parking spot in a parking lot or anytime I would be turning sharp at slow speeds. This last Saturday I was going down I-5 at about 70mph and noticed that I had lost all of my power steering. About 1/2 mile later I saw that my oil pressure was at zero. I was right at a off ramp so I pulled off. The motor started knocking as I came to a stop at a gas station right off the freeway. I shut it down and called a friend who picked me up with a car trailer.
As we towed it back to my shop I read on here about the front pulley needing to be torqued to 305# to drive the oil pump and the power steering pump. When I got it into my shop, I looked at the nut and it was finger loose. I torqued it down and started it up. It knocked twice as the oil pressure came up, then sounded smooth as ever. I figured I was in the clear, so I changed the oil and started it up and the knock was back. I listened through a redneck stethoscope (siphon tube) and the only place I could hear it through the tube was right behind the main pulley. At this point I figured I had spun a bearing so I began taking off the oil pans. What a PITA. Got it off finally this morning and pulled off my rod bearings, and they all look great. So at this point I am going to throw in new bearings since I already have them off and put the pans back on.
But the question remains, what is causing the knock? I am not familiar with what the different kinds of knocks sounds like, so my next guess is a lifter maybe, maybe a sheared lobe on the camshaft, possibly a wrist pin?
I am hoping someone has been down this road before and can offer some knowledge.

Thank you

 

[scottryana]

Please see if you can lay out your bearings from 1-6 and get some good pictures. If I remember correctly there is a little cryptic method with Toyota's bearings just make sure your parts guy understands that.

 

[Red Merle]

Do you have a WIX oil filter?

 

[scottryana]

Nope in this case he had a finger tight crank bolt that wasn't driving the oil pump. :-( One of the first signs is loss of power steering.

Do you have a WIX oil filter?

 

[Red Merle]

Nope in this case he had a finger tight crank bolt that wasn't driving the oil pump. :-( One of the first signs is loss of power steering.

How would that happen unless someone had been working in that area recently? 304 ftlbs is about as tight as anything on this truck is. What could knock that loose? Not saying it was oil filter related, I just associated a sudden drop in oil pressure to the possibility of another WIX victim.

 

[Red Merle]

-

 

[scottryana]

304ft/lbs is the right torque. I have had mechanics tighten it down thinking oh that is tight enough. (Happened to me in Texas) and I had the truck back about 3 months before it backed itself loose. Just like the OP, the power steering started feeling weak pulling out of parking lots, oil pressure looked even lower than normal on the gauge. I tightened it back up to 310ft/lbs and it hasn't come loose since.

How would that happen unless someone had been working in that area recently? 304 ftlbs is about as tight as anything on this truck is. What could knock that loose? Not saying it was oil filter related, I just associated a sudden drop in oil pressure to the possibility of another WIX victim.

 

[Red Merle]

304ft/lbs is the right torque. I have had mechanics tighten it down thinking oh that is tight enough. (Happened to me in Texas) and I had the truck back about 3 months before it backed itself loose. Just like the OP, the power steering started feeling weak pulling out of parking lots, oil pressure looked even lower than normal on the gauge. I tightened it back up to 310ft/lbs and it hasn't come loose since.

Ah, I see. That would make sense then. Guess I am glad I bought that 650 ftlb torque wrench then

 

[csj]

The filter that was on it was a Toyota filter and the one I replaced it with was a NAPA. I have no idea why the nut came loose. It hasn't been touched since I have owned it (3 years). I wasn't aware of the pulley driving the oil pump, and I thought that the steering going out was something related to my adjusting the steering gear about a month ago. I just figured I had over tightened the set screw. After tightening up the pulley, I turned the wheels back and forth with no problem. I can post pictures of the bearings tomorrow.

 

[slow95z]

it could be the gear on the steering pump. when you tightened up the front bolt you might have not had the teeth lined up just right and caused a tooth to chip. it will sound like the engine is coming apart if you do.

 

[baldilocks]

Your knock probably came back because of the Napa filter. They are made by Wix and several Mud members have had oil pressure problems caused by these Napa/Wix oil filters being defective. Go back to the Toyota filter, it’s actually a good filter in its price range.

There is a good bit of reading to be done on his subject most of it being posted within the last year to year and a half.

 

[thatcabledude]

What @slow95z said.

 

[baldilocks]

What @slow95z said.

Not likely, because the bolt was loose does not mean the gears were completely separated. That would mean the balancer and pulley were practically falling off the crank snout.

 

[Malleus]

A sheared cam lobe wouldn't knock, it would sound like a shotgun. Once.

If you had sheared a wrist pin, I think it's reasonable to assume you'd have a large hole in your block. Or at least a bad scratch on the cylinder wall...

 

[csj]

The interesting part to me is that the knock was gone after tightening the pulley, but came back as soon as I changed the oil. I don't think it has anything to do with the oil filter because a usually use the napa filter and this problem is clearly from loosing oil pressure. One thing that I forgot to mention is that there was about half a dozen metal shavings in the oil pump pickup screen. All of my cylinder walls look good so maybe not the wrist pin. Possibly a lifter?

 

[Malleus]

We can speculate about every part in the engine without helping you. You say you pulled the bearings. Did you pull the pistons? If so what did the rings look like? If not, why not? You already know what a job it is to remove the pans; it's not like you are likely to go back later and check them, without tearing the engine down.

If you've inspected the lower half, and thoroughly cleaned the pans while they were out, you've had the opportunity to verify that everything below the head is intact. If it is, you need to remove the valve cover and inspect the head. You should not have any metal "shavings" in your engine.

It's unwise to restart the engine without finding the root cause of this failure.

Regardless, we can't help without seeing what you're seeing.

 

[csj]

 

[csj]

One of my main bearings was groved with a piece of metal stuck to the end of the bearing. The rest look fine and the micrometer on the crank and bearings are all within specs. I think the metal that groved my main bearing came from somewhere else in the motor. At this point I am leaning towards a full rebuild or dropping in a Japanese import. 1800 bucks for one of those with 50k miles.

 

[slow95z]

i am sure you could get one locally for less than half that. post in the wanted section here to look for part-out threads. 50K JDM ebay miles is probably more like 250K miles.

 

[landtank]

Not sure that im following the time line corectly, but you haven't put everything back together yet and am thinking the bearings are ok.

I'd throw in some clevites and see what happens