# Loud diesel rattle below 2krpm, oil pressure light is flickering, timing chain?



## Tahnka (Nov 10, 2010)

Hello, I'm a big time newbie with Altimas and am hoping you can confirm my fears with this engine. I've read several topics and I'm thinking I have a timing chain problem. Will you please confirm?

I have a 1999 Altima with 144,000 miles. About a week ago it started making noise at idle that sounded similar to an old diesel engine. The oil light on the dash also started to flicker at idle.

A week later the thing is now so loud that it sounds like it's going to grind to a halt. The oil light is mostly solid. It doesn't sound like low oil/lifter rattle. I just had an oil change 3 weeks ago. The dipstick shows I have enough oil. It sounds like something within the engine is trying to gouge its way out. Scary loud now even at 3k rpm on the highway.

I'm thinking that even though I have enough oil in the pan, the oil isn't moving, which is causing the sensor to light? I've never ever replaced a timing chain before but from reading the posts, I'm thinking the really loud noise is related to the chain. The noise sounds like it's coming from beneath the black oil cap on top of the engine. Does it make sense that something wrong with the chain would cause the oil light to glow?

I read about the noisy guides in the model prior to mine but it seems a '99 doesn't have those? Anyone think this might be a known problem/fix? I'm hoping the oil light in addition to the noise might tell someone exactly what this is.


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## jdg (Aug 27, 2009)

Sounds like you're well on your way to an engine rebuild.
The noise could be a rod knock, could be lifters & the cam meeting each other in the bad way.
The sensor is lighting because you don't have enough oil pressure. You keep driving it like this and you'll be walking soon.
Take it down to your local mechanic and have him listen. A good mechanic will be able to tell right away if it's rod and/or main bearings, or a top end (i.e. cam) issue or whatever. Those noises aren't that hard to diagnose...especially when you've got an oil light to go with it.
If the problem was the timing chain tensioner, and only a timing chain tensioner, you would most likely NOT have an oil light to go with.


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## Tahnka (Nov 10, 2010)

Worse than a timing chain...yay...

I'm glad I asked. Thanks very much for the response.


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## jdg (Aug 27, 2009)

Yep... If I had to lay money on it, I'd say much worse than a timing chain. Although I could be wrong...
But, with the noises you describe, the oil light flickering, the rpm's you say you've driven with the noises and the lights, I'd venture to guess the damage has been done and it's only a matter of time before the engine seizes up or pieces/parts come flying out of the block at high velocity. Only way to figure it out for sure is to start tearing into it and start looking. First thing I'd do is get your hands on an old school handheld mechanical oil pressure gauge and plug it into your block and see what the oil pressure really is vs. relying on the gauge itself. If that shows a crappy reading, drop the oil pan and have a look-see at the oil pump and the pickup, the main and rod bearings and see what they feel like, and look and see how much crap (i.e. metal) is on the bottom of the oil pan.


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## altimanum1 (Jun 19, 2009)

Two things it can be...... 1 oil pump. 2 timing chain tensioner broken. I have a 98 altima and the lower timing chain tensioner broke making the chain loose. Remove the Oil pan and check for little broken pieces


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