rconnon

Hi Folks

I recently noticed a noise on cold start-up... I captured it on video, you can hear it here. http://1drv.ms/1F1rRCb

Ignore the position of the camera, i was focused more on the sound

Few pieces of information up front to eliminate the obvious questions and give more context.

• The noise only happens when the car is cold started, lasts for ~60sec
• The noise cannot be heard at idle, i need to lightly blip throttle (700-1300RPM)
• The sound appears to be coming from around the left side of the engine, near blower motor
• Doesn't matter if clutch pedal is depressed or not, i had thought it could be noisy throwout bearing
• Recently (1000 miles ago) replaced all the lower hydraulic lifters
• Lifters are normal in sound on start-up/warm at all RPM ranges
• Spark plugs and wires were done at same time as lifters, along with new caps, ignition rotors
• Fan bearing was replaced ~600 miles ago, painted fan / shroud, confirmed no rubbing
• Oil i'm using is Brad Penn 15W-40
• Zero performance loss, no shifting issues, engine pulls/sounds great.

The noise is noticeable lightly blipping the throttle after start, and if feathering the clutch/gas to maneuver the car you can also hear while in the above mentioned RPM range.

My gut tells me it has something to do with Intake/Injectors, not sure why... wondering if there is anything in that area that folks may think could be causing this...

earossi

I could not find the sound clip. Now, since there is no impact on performance and since car was recently worked on, my guess is that what you may be hearing is a part that is loose and vibrating due to resonance created in that low rpm range. Probably a metal bracket that is loose.

IainM

Left hand muffler has a detached baffle.

P-daddy

Intake/air ducts/blower tubing leaking?

justin-in-athens

The first thing I would do is pull both belts off to take the fan and alternator out of the equation.

BobbyT

Could it be the SAI pump? Easy to check this, just pull the SAI pump fuse (40 amp) located in the fuse/relay panel on the left bulkhead of the engine bay, then do a cold start to see if the noise is still present.

I had a similar noise, which turned out to be coming from the starter, located as suggested above by taking off the belts, then doing a cold start. Corrected by replacing the starter.

rconnon

MikeJ had also suggested SAI, i'll give the fuse pull a shot, thanks. Out of curiosity, what would cause the starter to make noise while the car is running? The starter isn't original, it was replaced around 20,000 miles ago

PRSWILL

Sounds metallic- could it be chain tensioners? Until they get properly lubricated they mak make some noise?

BobbyT

The noise my engine was making was only when starting, when the starter engaged, and for a very short time thereafter. Sort of a metallic screech, quite annoying. Apparently the starter bendix was worn or lacking lubrication, so it was hesitating in withdrawing.

Leander

I had something similar. It happened only when pulling away from cold start up. My mechanic thought it was the clutch plates. One new clutch later I still had the noise. I did some research and decided it was probably exhaust baffles and lived with it getting worse for several months. I had to replace an alternator belt and immediately the noise was much worse. I changed the fan bearing and the noise was gone.

rconnon

i know the exact noise, my starter did the same prior to replacement. this is tied to the RPM and while car is running.

rconnon

The fan bearing is new, it could be faulty, as i troubleshoot i'll remove belts again to verify, the issue is its hard to do consequtive repro attempts since it only happens on cold start

rconnon

Quick update here: The noise got worse and lasted longer as the weather turned cold, it would not go away after ~60 secs and started to happen at idle.

It turned out to be the Alternator bearings. Replace with a Porsche remanufactured, since a lot of folks here have had nothing good to say about the Bosch rebuilds.

Noise is gone

AOW162435

Excellent. I replaced my alternator a number of years ago for the same reason. Odd how spotty the service life on these is.

My 2001 4Runner is on its original alternator. I purchased the truck new and it currently has 343,000 miles...



Andreas

Mark Knop

Thanks for the update, 5 stars.