Macster

of engine at rear of car, sort of under/behind the air cleaner box.

"dry bearing noise" opinion of the owner of a nice looking and very red 964 Carrera with highly polished Fuchs wheels who I just happened to see him as i was looking at the car and asked him to give a listen.

Also, the opinion of a mechanic at a shop in downtown Tehachapi who I asked to look the car over before I drove it much more.

He had me drive the car up on a lift and then he put the car in the air and both mechanic and I were under the car with bright light in hand and neither of us found any signs of any fluid leaks. Water pump particularly came in for some serious inspection and showed no signs whatsoever of any coolant leak. And noise is clearly not coming from the water pump area.

Mechanic says its coming from higher up on engine and slighly to the right side, when viewing the car from the rear. I agree with his opinion of where the noise is coming from.

A/C on or off has no effect on noise. Cranking steering wheel from lock to lock -- engine idling, car stationary -- has no effect on noise.

In dash voltage gage reading doesn't show anything at all odd.

The noise is not loud but I hear it. Around idle it is present -- can't remember if it starts right up after cold engine start or the engine has to get warm first -- and with some engine speed the noise disappears or is lost in the general increase in engine noise level. Also, noise not steady but sort of comes and goes with no real pattern.

Coolant level just a bit under min line but has been that way for months. I do see some signs the cap may be leaking -- part # ends in "01" -- so I'll replace the cap with something newer come Tuesday.

With engine off I depressed and released clutch pedal 25 times and while pedal got a bit harder it didn't get that hard to depress. Then started engine and after just a few seconds of running pedal action once again very easy and light.

Oh, checked serpentine belt. Both edges are "sharp". Now when the water pump on my Boxster went bad the water pump bearing play -- barely noticable when checked with the belt removed -- allowed the pulley to **** slightly and inner edge of the belt rubbed on pulley side. Outer edge of belt was more rounded, just like it was when I installed it not too many weeks before the pump started acting up.

I don't have a new belt to compare to the way the old one feels so I don't know if this sharp edge thing is something to be concerned about, is significant, or ist just the way the is.

(Might add I checked the belt before the drive from near Mojave to Fresno and then after and I could detect no change in the belt's feel.)

Anyhow this noise spooked me and caused me to turn car around -- just west of Mojave CA on 58 highway -- and head it home to the barn.

The noise spooked me and so did finding the passenger side radiator not working. Just didn't see much to gain by risking a long -- 4 to 5K mile road trip -- with just one radiator fan.

This means I've postponed my road trip until after I have the car looked at by dealer's service department Tuesday.

Except for the noise and the radiator fan car was well behaved all the way down and back again. Even with one fan and temps in the Fresno area were in the mid-70s at least and I think I checked the car's outside temp reading once or twice and saw the temp in the mid 80s.

Was in the Fresno area and drove around until I got to the Porsche dealer. Service department closed on Saturday but I thought it worth a shot since I was going through Fresno anyhow on the way back home.

A/C blew nice and cold whenever I had it on and car even pulling hard in places (I love to climb mountain roads in a turbocharged car!) the engine coolant temperature gage needle hardly budged off the "180" mark. 'bout a half a needle width is all. Oil pressure at hot idle nearly 2 bars (Castrol Syntec 5w-50 with (now) 3K miles on it) and easily 4.5 bar at 3K rpms.

Let's see: Fuel economy for one fill up -- 250.5 miles -- was 24mpg. Another fill up after 251.4 miles got 22.8mpg. I think I filled up the car's tank 3 times but I can't put my hands on the credit card receipt.

Anyhow, not looking for help necessarily just touching base. Will report what mechanic finds as soon as he finds anything.

Sincerely,

Macster.

jpflip

Macster, how about the belt tensioner or one of the two deflection roller ?

http://www.6speedonline.com/forums/9...ing-noise.html

Macster

That's a good question and idea. Honestly I didn't even think it might be one of those.

However, in my defense I think I'm entitled to forget to think about the idler tensioner roller bearing though. A long time ago, when my 02 Boxster's belt was due to be replaced I bought new idler rollers with bearings and a new tensioner complete with roller and bearing.

Removed the belt and checked the idlers and tensioner rollers and decided since they felt ok, looked ok, thus were ok to leave them alone.

The new ones are still in the boxes and remain in the car along with a spare belt, just in case. The original idlers/bearings and tensioner/bearing are still in service and have lasted over 231K miles.

But thanks for the good idea.

Oh, I removed the coolant cap this AM before starting the engine. Wanted to rinse the cap off. It had collected some signs of anti-freeze stains on it.

Sure enough when I got cap off and turned it upside down it was clear that coolant had been coming out from somewhere related to the cap. There were several deposits of dried anti-freeze. (Sorry no pics, I was just not thinking clearly cause pics would have been nice to show what I found.)

Anyhow, I rinsed the cap thoroughly under hot running water then back at the car checked the fluid level in the plastic tank. Low. So low that even when I stuck a finger into the tank it failed to touch fluid.

Added nearly 1/2 gallon of distilled water just to bring the fluid level up to the minimum line.

Definitely the cap is bad.

My advice to any Turbo owner, heck make that any 996/986/987 owner, if the coolant cap part number on the cap doesn't end in the numbers "03" or "04" or something higher (the Turbo cap part number ends in "01" and my 02 Boxster's cap ended in "00") would be to order a new cap and next time the engine's dead cold to remove the old cap and replace it with the new cap.

Almost certainly the coolant cap will develop a leak.

Sincerely,

Macster.

$manager

power steering pump on it's way out? Right location...but you'd most likely notice it more as a high pitched whine. Run it up to 4-5K and shift.Listen closely for it. If that is what it is, you should be able to hear the whine dropping off quickly. My bet is tensioners....I just had the same issue. I replaced them and did the gt2 slave conversion...no more whine.

Land Jet

Mac, I had the belt tensioner go out. You need to pull the airbox to pinpoint it. It's a cheap fix comparatively. If it's the same one I had go out, it is just below the power steering pump. My tech misdiagnosed it as the power steering pump. $1400 later the sound was still there. Check the tensioner first.

Oak

Could be smog air pump starting to go

Macster

I think I agree. That's the right location. The power steering pump I think can be dismissed cause turning the steering wheel lock to lock with engine idling has no effect on the noise. I would think if it was the power steering pump the noise would be affected by this action.

Lucky for me the car is still covered by the "new" CPO warranty so whatever's the problem is not my problem, at least not my problem to pay for.

Going to have the coolant cap replaced. It is leaking.

Going to have the tech replace the serpentine belt too, while the tech's in there dealing with the noise source.

Going to have the 6-speed transmission fluid and differential fluid changed too. (Front diff fluid changed about a year ago.)

Since the air box has to come out might as well replace the air filter.

Sincerely,

Macster.

Macster

Air pump sounds pretty good, very quiet even. I think based on what the mechanic told me and plus my observation and what others have offered and with some additional thinking about it that the belt tensioner roller up close to the top of the engine the source of the noise.

Sincerely,

Macster.

Macster

To the best I can hear it the noise drops off, or is drowned out at higher engine speeds. I don't think it is the power steering pump.

I think the consensous is it is a belt tensioner roller bearing or perhaps an idler roller bearing.

Wish I had the day off when the car was going to be worked on. I'd love to take pics. But since I postponed my vacation I'm scheduled to be back in the office all this week at least.

Can't leave next week on vacation cause I would miss voting.

However, I have until 5pm Tuesday to get to the registrar of voters to get an absentee ballot. If I'm successful then I'll take next week off. Oh, providing the Turbo's out of the shop by then. I think it will be cause I believe (hope!) it is facing at most a two day stay in the shop.

Sincerely,

Macster.

Land Jet

Mac, that is the exact symptom I had, rpm related noise that is drowned out at higher engine speeds. Agree that it's a good idea to change the belt while it is apart.

biglicks

Macster, I have what I believe is the same issue with whine coming from behind the airbox. I have been told it is likely one of the tensioners or idler roller bearings. I am also told it is a complete engine out to fix the problem (8 hours of OPC labour to boot). What was the method employed for your fix?

PAULUNM

Not true, the airbox needs to be removed- that's about it.

biglicks

I am going to email them the picture and ask them if it was one of these they think needs changing, as indicated yesterday, or something else that needs a total engine removal. I am keen to see their reply. If anyone can detail the work involved, and level of difficulty, I guess a belt change it in car, therefore access to tensioners should be easy, it would be much appreciated.

Carlo_Carrera

Yes, belt tensioner. Easy fix. Remove air box and belt it is all right there.

biglicks

yep, found some good write up and photos etc online, I will go with the wd40 spray test first and see what goes silent.