Rushlow

Hello!

I've got an '86 NA that is making a strange noise when I open the throttle up a bit. I recorded a video of it and I was hoping someone might know what it is!


(sorry for the shaky recording)

The sound *seems* to be coming from an area near the idler pulley/distributor/intake manifold area but it's hard to tell.

It only occurs when the engine reaches about 1400 rpm

Recently replaced:
timing belt + tensioner
water pump
thermostat
serpentine belts

Possibly related info:

• Just did a timing belt job
• Car idles high (slightly above 1000 rpm)
• Hose from intake to IAC has a small crack in it and is currently wrapped with electrical tape, pending a new part.

Cheers!

Bobs 84 300ZX

Hi Rushlow, It really sounds like a bearing noise to me. I have been working on cars and motorcycles for years. Proper tools makes the job easier and many tools do not have to be expensive. See the attached pictures of a stethoscope tool that is one of my main stays and I use it often. After inserting the ear ends into your ears, you touch the end of the probe to various locations and listen to the amplified noises. Be very carful of rotating pulleys and belts so it doesn't get caught in one of them. It can pinpoint the location quite accurately. If you have never used one before, it can take a little practice to understand what the noise is telling you. A high pitched hiss could be a vacuum leak or a clicking or grinding noise could be a bad bearing. Check the pulley area of the AC compressor, water pump, power steering etc. Having changed the belts, I would confirm the pulley adjuster isn't too tight and giving a bearing noise fault. Good luck on your diagnosis. Thanks, Bob

Rushlow

Thanks Bob!

I'll swing by Princess Auto sometime this week and pick up an automotive stethoscope. Hopefully I'll be able to use it pinpoint the source!

I'll keep you (and other readers) up to date!

Cheers.