Thoughts on Engine Grinding Noise, Oil Light Comes On

I know diagnosing issues over the Internet is haphazard at best, but wondering what the thoughts are on an issue with my 1996 2.7L regular cab with 255,000 miles, motor rebuilt at 180,000 miles.

This morning when warming up the truck it started to make a clicking sound coming from the motor - sounded like something in the fan, but was coming from the motor.

Driving in I noticed a loss of power and when slowing down or stopping, the oil light comes on. Checked the oil and it is full. Shortly after that when decelerating/downshifting on a slight down hill, the oil light came on in conjunction with the check engine light and the engine cut out. I was actually just getting to my destination so I popped the clutch and it started back up and parked it.

Anyone experience this and/or thoughts? A few people at work said possibly a bad oil pump, possible bad injector or clogged fuel filter, or worse serious internal cam or crank issues.

 

I'm thinking oil pump for sure, since it doesn't get adequate pressure at low rpm. Anything else I don't know.

 

Does it run hot when this happens?
CEL come on?


I've never heard of an oil pump failing, in my 30 years experience with Toyotas. Something else may be causing a drop in pressure. Maybe a gummed up oil/sump pickup screen?

Or worse ...
Think of the pressure in your lawn sprinkler system. Pressure is fine until a pipe ruptures or head pops off. With no resistance, the pressure drops to almost nothing.

I'm no expert on the internals of a typical motor, but it could be a broken or loose internal motor part. Perhaps a rod journal bearing? Chain tensioner? With only 75k miles on the rebuild, this shouldn't happen, unless the re-builder took a few short cuts.

 

Drop the pan and see if there is any metal or gummy stuff on the filter screen. It could be an easy fix. If all that is good then I would think it is something internal. There are a butt ton of passages that the oil has to carry through.

 

I didn't notice a spike in the temp, but honestly I was so freaked out and preoccupied over the oil light coming on and the engine chattering that I wasn't actively monitoring the temp gauge.

The CEL came on a downhill stretch as I was approaching my destination and downshifting, and the CEL illuminated as it died.

That could be. I did have it out muddin Friday morning and buried it pretty good, but after a good power washing it ran like a raped ape all weekend until this morning's issues. I just don't see how mud or muck could have penetrated the oil pan.

Another Taco owner said that switching from conventional to full synthetic might have something to do with it.

History: Bought the truck a few weeks back, changed the oil & filter, rotors and pads, exhaust, and new rubber all around. No clue what the previous owner had in it oil-wise, but it was dangerously low (*had less than 3 qts in it when I took possession, got it home and changed the oil).

 

OK, here is a bit of advise from a professional tech. If the oil warning light comes on.... TURN OFF THE ENGINE! An oil warning light comes on when the oil pressure drops BELOW safe operating pressures. This means if you keep driving it, you are continuing to cause damage. Even if your oil pump is the failure, if you continued to drive the truck with low oil pressure, you have already caused damage to the engine bearings due to lack of lubrication. Switching from conventional to synthetic will NOT cause your oil pressure to drop and the engine to start making mechanical noises like that.

 

Yep, if I see the oil light on I'm shutting the engine off ASAP. If the engine was low on oil, that makes me think it already had some internal issues and finally they caught up with you. The previous owner pawned a turd off on you.

 

if its a 4x4 this is a real pita, 2wd prob not to bad

 

Yup, 4X4.

 

Here is my opinion: If you want to keep the truck, then err on the side of caution and have the engine rebuilt. The last thing you want to do is put a band aid on an arterial cut. Eventually it is going to pop through.

 

Yeah, I dunno - definitely in a jam. I paid $2,600 for the damn thing a few weeks back & shelled out another grand getting it road worthy for this to happen the day after the state inspection sticker is on. At this point, do sink more $ into it or cut my losses & sell it for parts...

 

If you are $3600 into a 4X4 Tacoma, you are doing good. They sell around here in running condition, even as old as a 1995 for 6-8 grand.

 

Thanks for the feedback, All!

Update: A buddy from work had a code reader in his truck. We plugged up with no error codes & everything looked good. So I turned her over & made it to the shop a couple miles down the road without the oil light coming on, losing power or stalling.

The shop is closing for the day so I'm leaving it overnight for them to checkout tomorrow & let me know what they think. One of the mechanics said is sounds like a timing chain issue when he drove it around back, so we'll see. Fingers crossed!

BamaToy, @ 75/hour for this shops hourly rate & assuming that it is the timing chain, what's a ballpark estimate for repair?

 

Josh, with a 4X4 you will be looking at a pretty decent labor charge for the timing chain. Oil pan has to come down and front cover removed to do this. Also could be a balance chain issue, which is right there as well. Either way you would be looking at 15.9 hours. At that labor rate, you should expect $1200 in labor if it is the timing chain, plus parts.

 

Put a new engine in it for that price. Especially since there might be other issues.

 

Thanks, Bill! I'll let you know what they say.

 

I am a bit confused here...if the motor stalls, the oil light SHOULD come on...so is the light coming on then the engine stops, or is the engine stopping and the light coming on.

If there is a failed main or rod bearing, then it should be more than "clicking".

I would probably put an enternal oil gage on first and see what the true oil pressure is, and if that is good, then start looking at why it might stall. I would be concerned about destroying the crankshaft/block and that would get expensive.

Howard

 

Yesterday morning the oil light was coming on when at a stop, or when decelerating. The oil light would only come on at low RPM (idle, stop, etc.). The one time it staled out, the oil light came on as did the CEL, and the engine cut out. I was actually decelerating down hill, so I popped the clutch and it started back up.

Yesterday afternoon driving it to the shop, there was no loss of power, oil light or CEL illuminating, but I was only going a 2 or 3 miles.

 

Shop just called and said it needs a new engine. Thinking about getting a second opinion.

 

Do not run it! Take it in ASAP. My buddy owns a shop and has replaced a motor due to no oil.