Dmanc

Hello everyone, I own a 2003 Nissan 350z (Touring Edition) with 164k miles.

While driving my car a few days ago I started to notice that my oil light on the dash would randomly come on sometimes and then go back off, I also noticed that when I turned the wheel to the left sharply it would come on almost every single time I turned the wheel then go back off when I corrected the wheel straight. I wasn't too worried about it. When I got home and drove across town maybe 2 miles I noticed a weird noise. At first this noise would rarely happen and was quiet. It didn't get louder as RPMs increased or become more frequent. I started looking up what it could be and how to fix it. The next day I had to drive to the store to pick something up and I noticed that the noise had gotten much louder, along with as the RPMs increasing the noise got more frequent. The car even did it at idle while it was parked. The noise sounds almost like something is loose and spinning, it sounds like it is coming from the right side of the engine (right side from inside the cabin, left side if you were looking at it with the hood open). I also noticed that the noise primarily sounds when I'm accelerating and then I let off the gas. Almost as if something is tight while driving and then once I let off the gas it gets loose again and bangs around. It's a scratchy noise and I'm sorry if my description isn't the best but it's a very hard noise to describe. On the way home I noticed a severe drop in oil pressure, the gauge was barely above 0 at idle and barely went up at all under acceleration. So I decided, with the oil light coming on and the oil pressure low I would check the oil of the car as I'm still around 2000 miles away from my next oil change. The dipstick looked normal. It had the normal amount of oil on it. I also tried to empty out the catch can the previous owner installed. (He told me to check it every so often and empty it out.) When I removed it I expected it to have oil in it, there was barely a drop in there in fact I even shook it and nothing came out. So I cleaned it up and reinstalled it onto the car exactly as it was before. I've started the car and tried to let it idle and look under the hood but it doesn't make the noise and I'm having trouble narrowing it down. I posted this problem on a 350z Facebook group but mostly all I got in response were guesses at the problem. One person told me that low oil pressure meant that I had starved the car of oil and that bearing clearances had changed and that by starting the car/driving it I was destroying the engine. I have no idea what he meant by bearing clearances as I'm not very knowledgeable on the internals of a Nissan engine (the most I've ever done as far as working on an engine was a head gasket swap and water pump and timing belt on an old civic). Does anyone know what this noise could be coming from and could it have something to do with the low oil pressure? I want to narrow it down myself and fix it to avoid the shady mechanics in my area and make sure it's done meticulously.

Any help would be greatly appreciated.

EDIT: Started the car today, when listening for the noise and trying to narrow it down I was moving the wheel back and forth. There was a popping noise and something on the left side of the engine began to smoke. I can't see down in there very well. Would this help narrow the problem down? (I'm taking the car to a mechanic this week but I'd like to try to solve it myself).

dcains

iTrader: (15)

Sounds like your rod bearings are gone, at least from your description. I certainly wouldn't even idle it without having a mechanic lok at it. You should have shut it down at the first sign of the oil light, but even then, the damage was probably already done. The gauge and warning light are there for a reason. Sorry for the reality check.

Dmanc

I was pretty far from home so I couldn't just stop the car, I would have had it towed home if I wasn't so far away. The reason I didn't really worry a lot about the oil light is because it would go off. If it had stayed on I would have thought there was something wrong. I figured maybe it could be something small like a sensor. Yes I know that they're there for a reason. I looked up a video of spun rod bearings and those make a completely different noise than what I was trying to describe.

dcains

iTrader: (15)

That's why I suggested taking it to a qualified mechanic - can't hear the noise from here, and the noise can certainly vary depending on the level of damage. Just my best guess from a distance, but no oil pressure always = serious bearing damage. The material they're made of can be scratched with your fingernail.

Dmanc

Right I understand. Well I really appreciate the help because I didn't even have an idea on what it could be. Hopefully it's not the bearings because I don't feel like ripping the engine apart.

Dmanc

Bump.

HCO_surfer

You need to take it to the shop. We can't diagnose your issue. Sounds like you ran into an oil issue and now have internal damage. Since you also have an issue whe turning the wheel it could also point to a second problem regarding your power steering or suspension.

RobPhoboS

If you've not changed the oil, get an analysis done - they send a kit, you siphon off a bit and send it away... post up the results (as it'll show certain metals in the oil if something is worn).
Or... take it to someone who knows what they are doing

Dmanc

I'm taking it to a shop tomorrow to have someone who specializes in Z Repair look at it. I just wanted to try to find out what it was myself and through the help of the forums. The reason I'm so confused is that my car doesn't have rod knock so if the con rod bearings were gone then the piston rod would be rattling against the crank. I'll update this post tomorrow after I get a diagnosis on what the problem could be.

RobPhoboS

Good luck!
BTW - for the future, just record some video of the noise, sling it on youtube, as it'll help you get some info faster from anyone here, and can potentially help someone else identify an issue too

gotama

Yo guys, I was searching the forums for strange noises or something similar and I found this thread so I'm posting my noise issue here.


I got this weird revving buzzing noise which can be heard here:




The buzzing sound happens at 3k rpm and at 4k rpm as can be seen clearly in the video at 20 seconds.


I have been having this issue for a while now and it does the same buzzing sounds while driving at the same rpm 3k and 4k. The buzzing sound goes away at high rpm.


I don't know if it is coming from the exhaust, the clutch, some hose vibrating against some metal, or hec it could be inside the engine itself.. I'm so lost!


I tried taking apart the exhaust, everything except the headers, and assembling them back, but the same noise still...


Anyone got any ideas or has gone through a similar noise ? before I take the engine apart and spend truck loads of cash to find this noise.. ? lol


Any help would be awesome