3rd & 4th Generation (1992–1996 & 1997–2001)Toyota Camry Discussion for years: 1992-1996 & 1997-2001
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This damage occured in a 4 cylinder 93 Camry. Somehow the oil filter came loose and the engine loss oil resulting in a loud knocking sound from the cylinder head area, as well as a light amount of white smoke coming from the right valve cover area. The knocking was steady with idle RPM's and increased with the RPM's when I gave it gas.
I've already disassembled the engine/cylinder head to be taken to a shop, but as I was removing components from the cylinder head, (a sensor and bracket or two) I also removed the spark plugs. 4th plug from the left was completely coated in motor oil where the plug boot attaches.
How could this have happened?? And could this have been the source of the knocking?
Oil on a spark plug is not going to create any sort of knocking. This is just an indication that the spark plug seals are leaking, and isn't anything of consequence when you are talking about oil starvation. As far as the knocking goes, I would look to the bottom end first.
When oil starvation happens, generally the first failure you will see is the connecting rod bearing. Keep in mind that this is where you have the most force on a bearing surface as a result of being connected directly to the piston, and the same (but to a lesser degree) goes for the crankshaft main bearings. The camshaft bearing surfaces in the head don't experience a great deal of force, so they are usually the last to go. The only other noise from the cylinder head area would be a valve noise, something not likely to occur because of oil starvation.
If you have a bad knocking noise, you aren't going to have to send anything to a machine shop to determine where the problem is; you'll know it when you see it. My advice would be to first drain the oil through a strainer and look for particles. Drop the oil pan and see if there isn't a load of glitter in the bottom. If I remember correctly, you can get to one or two rod bearing caps after the oil pan is off. Pop one off and look at the bearing.
If I got something damaged in the block, I'd be in some trouble. I had to remove an engine support, to remove the cylinder head, so I got the engine supported by a block and jack from underneath. I already drained the oil and I don't think I'd be able to drop the oil pan.
I originally thought the damage was in the cylinder head, being that's where the knocking was coming from. I figured it was a broken cylinder head component, so right away I decided to remove it, and have it repaired.
I don't have the proper equiptment to remove the block, so I may be screwed if this is the case.
No offense to Qslim, while the facts he mentioned may be true and are appreciated, I would like some more feedback on this.
To elaborate on the knocking sound, it was more like a loud clack noise......sounded like: CLACK! CLACK! CLACK! CLACK! CLACK!
Last edited by CaliAuto909; 05-29-2008 at 03:35 PM.
Reason: Added to post.
With the head off and the fuel system disconnected, and making sure no loose parts are lying around in
the engine, you can now crank over the engine and find out if it's still knocking.
Odds are that it is.
A loss of oil pressure causes bottom end damage, not top end damage. There's not any reason at all
to even suspect top end damage before checking the bottom end out first in a situation like that.
With the head off and the fuel system disconnected, and making sure no loose parts are lying around in
the engine, you can now crank over the engine and find out if it's still knocking.
Odds are that it is.
A loss of oil pressure causes bottom end damage, not top end damage. There's not any reason at all
to even suspect top end damage before checking the bottom end out first in a situation like that.
CJ
CMs on the right track, but turning the engine by hand isn't going to yield any results. The knocking produced from oil starvation comes from the space created in the bearing surface as the metal wears away, we're talking thousands of inches. The knock happens when the pistons are driven downward from the combustion, and this force can't be replicated by hand-turning an engine.
I never said turn it by hand. Crank it over with the starter. So long as the fuel system is disconnected and
there are no loose parts, this is safe for the (rest of) the engine.
I never said turn it by hand. Crank it over with the starter. So long as the fuel system is disconnected and
there are no loose parts, this is safe for the (rest of) the engine.
CJ
WOW! Never heard of that before.
Got a couple questions.
1. I've got it at TDC right now. How would I reset it to TDC #1 spark?
2. Would cranking it with just the starter produce enough RPM's to produce the noise I'm looking for?
Also, to remind you, I've drained the oil and would be turning it over with no oil.
I never said turn it by hand. Crank it over with the starter. So long as the fuel system is disconnected and
there are no loose parts, this is safe for the (rest of) the engine.
Got a couple questions.
1. I've got it at TDC right now. How would I reset it to TDC #1 spark?
2. Would cranking it with just the starter produce enough RPM's to produce the noise I'm looking for?
Also, to remind you, I've drained the oil and would be turning it over with no oil.
1) Well, with the head off, there really isn't any "spark" TDC, only TDC and BDC. If you want to be at top dead center, then the piston in the first cylinder will be at the top of its stroke. It's not until you install the head that four strokes become relevant. Do you still have the head off?
2) I don't think that the starter is a reliable way to replicate engine knock. If you think about it, the force is being applied in a completely different way than if the engine were running. During combustion, the piston is driven downward onto the crank lobe where the bearing takes all that load, and this is usually the first to have problems when oil starvation happens. When the starter is turning the engine, the crank is being turned from the flywheel, and there isn't any of this force driving the pistons down.
You can try it though, the fact that there isn't any oil won't matter if the starter spins the crank for a few seconds.
So there isn't any way you can pull the oil pan off, huh?
1) Well, with the head off, there really isn't any "spark" TDC, only TDC and BDC. If you want to be at top dead center, then the piston in the first cylinder will be at the top of its stroke. It's not until you install the head that four strokes become relevant. Do you still have the head off?
2) I don't think that the starter is a reliable way to replicate engine knock. If you think about it, the force is being applied in a completely different way than if the engine were running. During combustion, the piston is driven downward onto the crank lobe where the bearing takes all that load, and this is usually the first to have problems when oil starvation happens. When the starter is turning the engine, the crank is being turned from the flywheel, and there isn't any of this force driving the pistons down.
You can try it though, the fact that there isn't any oil won't matter if the starter spins the crank for a few seconds.
So there isn't any way you can pull the oil pan off, huh?
1. Okay, so resetting it to TDC wouldn't be a problem. The engine is still disassembled and the head is still off.
2. Hmm! Good point. Thanks!
If I can support the engine from somewhere else,to remove the jack from underneath the oil pan I can do it.
The knocking is obviously the main concern here. But you mention that the top of the plug (not the electrode) was covered in oil. That can happen if the gasket under the valve cover plug nut (the 30 mm nut) is torn or loose. Typically, it's no big deal. You may have a couple of tablespoons of oil that leaks into the tube. Normally you can torque down the 30 mm nut and it fixes this. Sometimes the tube itself is leaking but very seldom.
I would be very surprised if this contributed to your knocking problem.
Kep
__________________
Often, it's the loose screw between the steering wheel and the driver's seat that needs to be fixed first!
The knocking is obviously the main concern here. But you mention that the top of the plug (not the electrode) was covered in oil. That can happen if the gasket under the valve cover plug nut (the 30 mm nut) is torn or loose. Typically, it's no big deal. You may have a couple of tablespoons of oil that leaks into the tube. Normally you can torque down the 30 mm nut and it fixes this. Sometimes the tube itself is leaking but very seldom.
I would be very surprised if this contributed to your knocking problem.
Kep
I was told pretty much the same thing. It's either the large valve cover nut was loose, as you mentioned, or the spark plug tube was loose, which actually screws on/off the head.
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