# Not sure what is wrong with my Sentra



## cbh972 (Apr 15, 2011)

I drive a 1994 Nissan Sentra. Yesterday, the car started making a loud noise when I accelerate past 25mph. I'm not really sure how to describe the noise, but it sounds kind of like a chain saw. Could it be the transmission? Also, the car is due for an oil change, if that info would help.


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## jdg (Aug 27, 2009)

A metallic buzzing type noise that goes away eventually as you get faster?
Or just keeps getting louder and louder and is completely abnormal and sounds like it's going to destroy something?


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## cbh972 (Apr 15, 2011)

It's not a metallic noise. It gets very loud and then plateaus. It sounds like someone is driving a motorcycle under my hood.


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## jdg (Aug 27, 2009)

Is the sound road speed dependent?
Engine speed dependent?
Gear dependent?
In other words, is the noise dependent on the SPEED you are DRIVING or the SPEED of the engine regardless of the SPEED of the VEHICLE?


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## cbh972 (Apr 15, 2011)

Well, when I press my foot on the gas pedal at around 0-20mph, the car is fine. When I press on the pedal over 25, then the noise begins. But if I get up to 25, 30, or 40mph, etc and then take my foot off the gas and let it coast, the noise stops.


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## jdg (Aug 27, 2009)

And again, is the noise ENGINE speed dependent or VEHICLE speed dependent?
Rev it up in neutral WITHOUT MOVING and see if you can get it to make the noise at all.
Gotta start eliminating moving parts somehow right? If you aren't moving, that'll eliminate the driveshafts, wheel bearings, tires, etc. Right?


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## cbh972 (Apr 15, 2011)

I revved it in neutral and it still makes the noise.


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## rogoman (Dec 16, 2004)

cbh972 said:


> I revved it in neutral and it still makes the noise.


Since the noise seems to be coming from the engine, first eliminate the external accessories such as the water pump, alternator, power steering and A/C compressor. Remove all the front belts, then start the engine up. If the noise goes away, then it's one of the accessories. Now install one belt at a time to pinpoint the accessory.


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## Raphenry (Aug 18, 2010)

Did you find the cause?????


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## Vertigopills (Mar 28, 2008)

Change oil and filter, see if that helps. Also, do you have a timing belt or timing chain? If timing chain, check the tension and lubrication, see if it needs replacement or not.


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