# 2005 Pathfinder whining/buzzing noise from engine



## RyanG77 (Jun 17, 2015)

I just bought a used 2005 Pathfinder with 79k miles on it and just started hearing a noise coming from the engine. Since I just bought it, I have no idea whether this is a "normal" noise, or if it is indicating a problem. The vehicle came with a 3mo/3k mile power-train warranty, so if it is an issue, I need to get it addressed while it's within the warranty period.

I have done a bunch of searching and was concerned that this noise coming from the top-front of engine may be the timing chain (or specifically the idler/tensioners). However, the frequency/pitch of the noise does not change with engine RPM, which leads me to think that it's NOT the timing chain...so I am curious what else it might be.

What I am experiencing is this: When the engine is first started, the noise is usually absent. Once the noise is there and I turn off the engine and then restart it, the noise goes away for some period of time. The noise usually develops after driving, or revving the engine while parked, and is not always there. When standing next to the front of the vehicle it is very noticeable (noticeably louder than injector clatter and cooling fan volume), but cannot be heard inside the cab with the windows up. When I vary the engine RPM while parked, the tone and volume of the whine/buzz varies, but does not change pitch or frequency. 

It does not sound like a bearing going out either..my semi-trained ear says its more like a triangle or square wave that is around 100 Hz or so. I wonder if it is perhaps noise from the stepper motors/solenoids for the variable cams?


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## smj999smj (Jan 1, 2006)

The variable timing uses actuators that control oil to the variable timing gears; you won't hear them working if they are working normally. It's hard to diagnose a noise we can't hear for ourselves. The upper chain issues make a whining noise that increases with engine RPM and sounds very much like a bad or failing P/S pump (if you owned a Ford in the '80s, you are probably familiar with the noise!). I have heard of some noise issues on 05 models due to the power valve assy. on the front of the intake plenum (refer part code "14510" on the part diagram linked below). You may want to have a Nissan dealer check it out while it's still under warranty.

2005 Nissan Pathfinder Manifold - NissanPartsDeal.com


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## RyanG77 (Jun 17, 2015)

Ive been driving around for the last week and I think the issue was in fact the cam timing solenoids. 

The vehicle has been sitting at the dealer for a while, the previous owners drove it very little, and I have no idea how they maintained the vehicle. I just changed the oil with some high quality synthetic with high levels of detergent (Mobile 1 High Mileage), and the noise seems to have gone from consistent, to only "buzzing" when I let off the throttle, to barely noticeable under any condition over the last week. I think what may have happened was possibly some sludge was interfering with normal operation of the cam timing solenoids. My theory is that the ECU was sending a PWM signal to the solenoid to move, but it wasn't able to move freely and was just sitting there "buzzing" while trying to move. Between normal driving increasing oil flow through that area, and the high level of detergents in the fresh oil, it seems that (assuming my theory is correct) the sludge has been dissolved, and things are working normally now. I will keep monitoring it and update here if anything changes...

On another note..and perhaps I should start a new thread for this...but I have it into the tranny shop today for a drain, filter and fill, and to inspect the fluid for signs of oil/coolant leakage. As a preventative measure, would you guys advise me to have them divorce the existing (OEM I think) tranny cooler from the primary radiator to prevent future leakage, or just leave it as-is...or the most expensive (but probably best) option, replace the radiator with a new one but keep the tranny cooling circuit as is (closed circuit, transmission to primary radiator to external cooler and back to tranny)? I don't really want to drop $500-$800 for a new radiator, but IMO, it's cheap insurance against a tranny failure...


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## smj999smj (Jan 1, 2006)

If you don't tow heavy loads or live in an area that sees extremely cold temperatures, you can probably make due with the "bypass method." Me, personally, went with an aftermarket radiator. Generic radiators sell for as low as $74 on Ebay. Some opt for a Spectra Premium radiator, which sells in the $120 range and has a two-year warranty. The only aftermarket radiator I have heard have problems is the recently released, all-aluminum, CSF radiator sold by Stillen for $350.00
I'm not sure I agree with your theory, but anything's possible. The reason I don't agree is that usually when the variable timing gears aren't working, usually due to sludge, they slack up and the chain makes a loud, rattle noise. This was a common problem on the older J30 Maximas with the DOHC V6.


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