Hampster wheel in engine?

[99-996]

i think i have a pulley bearing going out on my 99 996 c2 cab.

when i start my car, occasionally i get a loud squeal...not a belt. when driving at normal rpm (2500-3500) then let off i can hear what sounds like a squeaky hamster wheel...

i think it is the pulley to the right of the alternator and under the oil filler tube.

any ideas before i take it to the dealer.

Thanks,

Erik

[Loren]

Very likely you are right.

It is not too hard to change but don't wait long - sometime when they break they can take out the alternator and more...

[99-996]

Very likely you are right.

It is not too hard to change but don't wait long - sometime when they break they can take out the alternator and more...

Thanks Loren.

i will call the dealer to get the number and replace that. Looks to be just the one bolt holding it there...

[99-996]

Very likely you are right.

It is not too hard to change but don't wait long - sometime when they break they can take out the alternator and more...

Thanks Loren.

i will call the dealer to get the number and replace that. Looks to be just the one bolt holding it there...

i think i found them. there is an upper and a lower. they are $80 each.

996-102-118-56-M100

Drive Belt Idle Roller Upper (on Engine Console), Carrera (1999-05) (Tiptronic) Carrera 4 (1999-05) (Tiptronic)

Brand: Genuine Porsche [More Info]

996-102-119-58-M100

Drive Belt Idle Roller Lower (on Engine Case), Carrera (1999-05) (Tiptronic) Carrera 4 (1999-05) (Tiptronic)

Brand: Genuine Porsche [More Info]

[355bhp]

when i start my car, occasionally i get a loud squeal...not a belt. when driving at normal rpm (2500-3500) then let off i can hear what sounds like a squeaky hamster wheel.

A 300bhp hamster wheel to be sure. . .

[phillipj]

Double check first to make sure there isn't a real hamster in your engine bay. I have heard of rougue hamsters attacking random Porsches for no apparent reason... :lol:

[99-996]

Double check first to make sure there isn't a real hamster in your engine bay. I have heard of rougue hamsters attacking random Porsches for no apparent reason... :lol:

i also have heard of this...after further inspection, no hamster!

[99-996]

when i start my car, occasionally i get a loud squeal...not a belt. when driving at normal rpm (2500-3500) then let off i can hear what sounds like a squeaky hamster wheel.

A 300bhp hamster wheel to be sure. . .

i hope after removal of this powerful creature i still have the same acceleration....if not i will re-instal that critter and begin a full marketing campaign for cheap hp increase!

[phillipj]

:clapping: :clapping: :clapping:

[mls12]

I have been chasing a hamster in my 90,000 mile 996 engine for a year now. The hamster finally made its noise for my Porsche tech. The diagnosis was a squeaky bearing in the oil scavenger pump. I have yet to look up the engine diagram to see where this part sits, but my tech said it was in the cam housing.

Sound also only happened at 3,000 rpm.

The tech said he has only every had one other 996 with this problem. I will pick up my car Wednesday, and hope the hamster will be dead. This comes after replacing an idler pulley thought to be the problem.

[99-996]

I have been chasing a hamster in my 90,000 mile 996 engine for a year now. The hamster finally made its noise for my Porsche tech. The diagnosis was a squeaky bearing in the oil scavenger pump. I have yet to look up the engine diagram to see where this part sits, but my tech said it was in the cam housing.

Sound also only happened at 3,000 rpm.

The tech said he has only every had one other 996 with this problem. I will pick up my car Wednesday, and hope the hamster will be dead. This comes after replacing an idler pulley thought to be the problem.

that sounds like a much more expensive hampster. i ordered the pulley and am hoping it cures it...nervously awaiting...

[deanslist.us]

I had a squealy sound coming from my car as well, and the mechanics thought it was the pulleys too. But the sound was consistent even after removing the belt completely...turned out to be loose spark plugs.

[bmohr]

glad he/you caught that it time...if you hadn't it would have been lights out for your 3.4

[deanslist.us]

glad he/you caught that it time...if you hadn't it would have been lights out for your 3.4

for mine?

[mkazemi71]

i think i have a pulley bearing going out on my 99 996 c2 cab.

when i start my car, occasionally i get a loud squeal...not a belt. when driving at normal rpm (2500-3500) then let off i can hear what sounds like a squeaky hamster wheel...

i think it is the pulley to the right of the alternator and under the oil filler tube.

any ideas before i take it to the dealer.

Thanks,

Erik

I had this on my 99 996 I chased this **** noise for weeks. I started at about 2850 rpm and by 3000 rpm turned into a high pitch sound from the radio. once past 3000 went away (well I could not hear it at least). Turned out the rear bearing in the alternator is a sealed unit that had water get into it. I took it apart and fixed it with a $25 bearing from a local parts store. Just matched up part numbers from the old one. You can take the belt off of the car and spin the pulleys by hand and see which one it is to be sure. Good luck. Careful with techs they have expensive habits they need to pay for.

[ultramens]

other the noise, what does a failing pulley look like? After I take my polybelt off, what should i look for (looseness?)

[bmohr]

glad he/you caught that it time...if you hadn't it would have been lights out for your 3.4

for mine?

no, the scavenger pump ceasing up would end it..not loose spark plugs

[deanslist.us]

glad he/you caught that it time...if you hadn't it would have been lights out for your 3.4

for mine?

no, the scavenger pump ceasing up would end it..not loose spark plugs

oh thank god

[mls12]

So I had the scavenger pump replaced that I mentioned earlier as my hamster. Turns out the sound remained and it continued to be at 2800-3000 rpm. Since my extended, after-market warranty was about to expire, I had the Porsche dealer (same one that replaced the scavenger pump) immediately re-examine the car. After what I think was several hours of searching, the Porsche tech determined the hamster sound was the Intermediate Shaft Bearing.

The good news is that had the IMS bearing not been replaced before it failed, the engine would have been irreparably damaged, as described in other posts. My Porsche tech says that the latter 2005-on IMS and bearing are much improved and I am to receive them.

The extra good news is that my warranty company finally approved paying for the parts (shaft and bearing) and labor to replace it. ($4,500 repair, the case had to be split).

I spent some time with the Porsche tech trying to recreate the sound at high-idle in neutral and the best I can describe the sound is like that of a loose exhaust clamp that is only audible as a sympathetic vibration.

I will post again when I have the car back, supposedly later this week. Though my Porsche dealer was great in catching this problem and dealing with the less than congenial warranty company, I always feel like a second-class citizen at their shop as I have a six year-old high-mileage C4S that doesn't seem to earn me much in the way of a loaner car or expeditious service.

[99-996]

so i replaced the idler pulley and the noise continues. it still only happens when i start it and i can occasionally hear a trace of it when driving...barely noticeable when driving, not near the 2 second squeal i get at start. the tech said it might also be the air oil separator...the part is not expensive ($150) but i hear the labor quote at 6-8 hours. i had a friend start it while listening and it does sound like it comes from the alternator (which is why i replaced that idler pulley). guess i will try to replace that bearing that mkazemi71 was talking about.

[flyingpenguin]

so i replaced the idler pulley and the noise continues. it still only happens when i start it and i can occasionally hear a trace of it when driving...barely noticeable when driving, not near the 2 second squeal i get at start. the tech said it might also be the air oil separator...the part is not expensive ($150) but i hear the labor quote at 6-8 hours. i had a friend start it while listening and it does sound like it comes from the alternator (which is why i replaced that idler pulley). guess i will try to replace that bearing that mkazemi71 was talking about.

Another possible source is a dried out end cap on your starter motor. Fairly easy DIY once you get the hang of removing the alternator.

JP

[mls12]

I promised I would reply to report on the outcome of replacing my IMS bearing. Simply, it did not work. The hamster is still there! No worse or better.

A better description of the sound is perhaps what an out-of-balance metal radiator fan might sound like when it rubs against a metal shroud surrounding it. The sound occurs regardless of whether accelerating, decelerating or maintaining RPMs. Clutch action in/out has no affect on sound. Sound happens at speed or stopped. The main cause of the sound is RPMs. The sound is most prominent at 3,050 RPMs.

In search of silencing the hamster, the following have been replaced:

Alternator (actually it died)

Deflection (Idle) Pulley

Both oil scavenger pumps

Water Pump (not thought to be problem, but had 90k miles on it. Preventatively replaced)

Intermediate Shaft and Bearing: a $7,200 job (connecting rod bearings done too)

Additionally, I had the spark plugs replaced when the case was split. So it's not the plugs as it was for a prior contributor.

Fortunately I had an extended warranty that covered all of the above, save for a few hundred dollars of deductibles. However, the warranty is now expired. The engine was completely and internally examined as part of splitting the case to replace the IMS and bearing. The report was good and little wear was noted on my 90,000 mile engine.

I remain convinced the sound is external to the engine and believe it belt driven in nature. At this point, the hamster hunt costs will be 100% born by me. My immediate conclusion is to continue driving the car until the noisy part breaks or the noise becomes so loud and constant that it can be readily diagnosed on the lift. However, I will be taking the car in to the Porsche dealer for the tech to inspect the soundness of his work after a 500 mile break-in of the 're-build'. I would love it if anyone had suggestions I could give him.

Four things I learned as part of the Porsche Dealer's replacement of the IMS and bearing:

1. While, Porsche, the Porsche dealer and warranty company all knew of the IMS problem on 996's I don't think any had replaced the IMS bearing prior to its completely failure that necessitates an engine repair. My Porsche tech took forever to complete this repair. Rather, this problem seems to be universally addressed by replacing the engine when the IMS bearing blows the engine up.

2. The replacement of the IMS and bearing took 9 weeks. Porsche dealer/tech blamed it on warranty company being slow. Service manager said if you try to rush the warranty company's adjuster, the warranty company will hold out hoping you, the car owner, will just pay for the repair to get the car back. I think it also that the dealer probably barely covered labor costs due to my tech's inexperience.

3. An extended warranty probably makes a lot of sense for a 996 engine, if you can get one fairly priced.

4. The Porsche tech said that 996 turbos are much more reliable (???) as they do not have the IMS? IS this true? Tech said the 996 turbo had the air-cooled block, sans IMS problem.

I am tempted to take the car to a Porsche speed shop for a second opinion.