Just got a 2002 pathfinder. mechanically everything seems ok. except when the engine is started, especially in cold weather or when the engine is cold, there is a high pitch screeching noise. this goes away after not even a minute after the engine runs and starts to warm up.. my guess is some sort of bearing/lubricant in something spinning (a/c, alternator, power brake pump)? anything else anyone can suggest? guess i should get it check out real soon just to make sure?

if its not a belt , it might be a broken fan clutch, other members had that problem too, the sound comes on when the fan isnt engaged but once the engine warms up and the fan engages, the sound goes away.

Im having the same exact issue on my 01. Would love to know a simple/easy fix for this.

Serpentine belts, I imagine. How old are they?

i have a similar issue. thought it was the belts, nope. thought it was the idler pulley, nope.

started it with no belts and it didnt make the noise. put ac belt back on, no noise. put ps alt belt back on and it made the noise. so i figure its the fan clutch, ps pulley or the alt pulley. still havent fix it yet.

so my question is how long can i ride around without actually getting this thing fixed? i got about 1k miles to go before the next oil change. i think i can go another 1k miles without the car crapping out on me?

yesterday it was around 80 in dallas and the car didnt make the noise. starting to think this a tempature issue. maybe some cold bearing grease? my noise goes away when the car gets warmed up.

I also have an 01 that screeches until the engine warms up.

Typically, the noise is from a loose belt, which can be easily solved by tightening the idler pully.

Waxfree, if you're sure it's not squeaking from a loose belt, I'd grab a mechanic's stethoscope and see if you can identify exactly where the noise is coming from. They're usually around $10 - $20 and are a great tool to have. Just be careful not to get it caught in the belt.

sounds like the OP already narrowed it down. it could be a bad bearing in the tensioner/idler pulley. it could also be the water pump. a dry water pump will screech until the coolant has begun circulating. check your coolant level. IIRC, the water pump is also on that same belt.

My 02 Has the same problem. 15 seconds of horrible screeching on cold mornings and throttle sensitive screeching until engine is warmed up completely. My dilemma is that the only place I really trust to find and fix this problem is the dealership, But I'm scared of the inevitable butt rape on price!

adjust the belts a little tighter and problem will be solved belts strech over time

wildpig wrote:Just got a 2002 pathfinder. mechanically everything seems ok. except when the engine is started, especially in cold weather or when the engine is cold, there is a high pitch screeching noise. this goes away after not even a minute after the engine runs and starts to warm up.. my guess is some sort of bearing/lubricant in something spinning (a/c, alternator, power brake pump)? anything else anyone can suggest? guess i should get it check out real soon just to make sure?

I had this problem two winters ago...To solve it, I first tried new belts...problem not fixed. Next, I loosened and removed the idler pulleys and applied some all purpose grease on the front/back of the bearing. Squeaking gone and has not returned for two years at any temperature.

To remove idler pulleys, make sure engine is off. Loosen (do NOT remove) the front nut on the pulley. Next, turn the tension adjustment bolt (directly below, hex head) in the direction to take tension away (counter-clockwise). Once sufficient tension is taken away, remove the front pulley nut and remove the pulley. Watch and pay attention for any washer(s) that may be present. Inspect, apply (small amount) grease to bearing and pulley shaft; put back on pulley shaft.

Repeat for the second idler pulley.

Before tightening front pulley nut to 19-23 ft/lbs (26-32 N-m), adjust tension on the alt/ps pump/fan pulley belt to 3.5-4.5mm (new belt) or 4-5mm (used belt) of deflection using an applied force of 22lbs (10Kg). Deflection is measured mid-way between the ps pump and the fan pulley. When proper deflection is reached, tighten idler pulley nut to spec above.

Deflection on on the A/C comp belt should be 8-9mm (new belt) or 9-10mm (used belt) using an applied force of 22lbs (10Kg) mid-way between the A/C comp and crank pulley. Tighten pulley nut to the spec above and you should be squeak free.

All torque and measurement info taken from Service manual, Section MA, page MA-14.

I just greased my 2 idler pulleys because my 2 new belts didn't help w/ the noise. So far zero noise.

did you guys open up the pulley and grease the bearings or just apply grease to the outside of the pulley?

thanks

I just took the pulleys off, cleaned and greased both side of the pulleys

I had this issue, and this is what fixed it for me

K03sport wrote: To remove idler pulleys, make sure engine is off. Loosen (do NOT remove) the front nut on the pulley. Next, turn the tension adjustment bolt (directly below, hex head) in the direction to take tension away (counter-clockwise). Once sufficient tension is taken away, remove the front pulley nut and remove the pulley. Watch and pay attention for any washer(s) that may be present. Inspect, apply (small amount) grease to bearing and pulley shaft; put back on pulley shaft.

Repeat for the second idler pulley.

Before tightening front pulley nut to 19-23 ft/lbs (26-32 N-m), adjust tension on the alt/ps pump/fan pulley belt to 3.5-4.5mm (new belt) or 4-5mm (used belt) of deflection using an applied force of 22lbs (10Kg). Deflection is measured mid-way between the ps pump and the fan pulley. When proper deflection is reached, tighten idler pulley nut to spec above.

Deflection on on the A/C comp belt should be 8-9mm (new belt) or 9-10mm (used belt) using an applied force of 22lbs (10Kg) mid-way between the A/C comp and crank pulley. Tighten pulley nut to the spec above and you should be squeak free.

All torque and measurement info taken from Service manual, Section MA, page MA-14.

So i take that i can probably drive my car for at least a few more thousand miles til next oil change without whatvever causing this screeching noise to cause any major problem? sound like several other members been drivin around for a while w the screeching noise...

wildpig wrote:So i take that i can probably drive my car for at least a few more thousand miles til next oil change without whatvever causing this screeching noise to cause any major problem? sound like several other members been drivin around for a while w the screeching noise...

Mine is more of a ticking noise which came back after few days of greasing my pulleys

i just changed the fan clutch on mine and the noise is GONE!!!!!!