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Join Date: Dec 2002
Location: In my car.
Posts: 396
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Strange front end noise.
I am encountering a strange front end noise. It appears to be coming from the front drivers side. It only does it when going above about 20mph, and increases in frequency as speed increases until it reaches an apparent maximum frequency at about 45mph.
It sounds exactly like water coming out of a sprinkler head, or perhaps what a totally unlubricated wheel bearing might sound like. In order to shoot this problem, I have replaced both front driver's wheel bearings and races, and I have taped over a broken fog light (light noise?) and power antenna hole. I have also put in a new speedometer cable. It is firmly anchored in the end of the grease cap. Water bubbles circulating through the coolant system/filling the overflow tank maybe? It has always made this sound.
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I am blessed/cursed with these cars: BMW 318iS 1991 BMW 325iS 1988 Volvo 740 Turbo Wagon 1992 Quote of the week: "This chemical is known to cause Birth Defects in California." Poor Californians, they are always getting the short end of it, and now this? |
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12-23-2002, 02:55 PM
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Warped brake disk.
Disk pads worn down to metal. Bad soon to break speedo cable.
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Hugh - So Cal 83 944 Driver Person NOT a 'real' Porsche -- Its Better!!!! When was the last time you changed your timing and balance belts and/or cam chain and tensioner? New Users please add your car's year and model to your signature line! Never break more than you fix! |
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12-24-2002, 11:24 AM
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Join Date: Dec 2002
Location: In my car.
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Not any of them...
Brake pads-Almost new. You could have told me they were new last week and I would have believed you.
Speedometer cable-Brand new, from pelicanparts. Just installed it because I knew it was bad in an attempt to stop the noise. Brake Disks- Checked for straighness, and they were still good. Other suggestions?
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I am blessed/cursed with these cars: BMW 318iS 1991 BMW 325iS 1988 Volvo 740 Turbo Wagon 1992 Quote of the week: "This chemical is known to cause Birth Defects in California." Poor Californians, they are always getting the short end of it, and now this? |
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12-24-2002, 04:28 PM
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Intriguing!!!
No noise before 20 mph? Have you had someone drive next to you and listen for the same noise? Or can you only hear it from your drivers position?
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Hugh - So Cal 83 944 Driver Person NOT a 'real' Porsche -- Its Better!!!! When was the last time you changed your timing and balance belts and/or cam chain and tensioner? New Users please add your car's year and model to your signature line! Never break more than you fix! |
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12-24-2002, 05:00 PM
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Registered
Join Date: Dec 2002
Location: In my car.
Posts: 396
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More info.
Passenger does not hear the sound. If it occurs before 20mph, the frequency is really too low to be detected. I have not had anyone drive next to me so far to see if they can see what it is.
My current theory, which I have no way to test, is that what I am hearing is coolant squirting into the coolant recovery tank. Perhaps one of the hoses or nozzles has calcium buildup or something and is making the noise. It would make some sense for it to increase in this case as speed increases, as increases in speed would generally make the water pump turn faster, yes? Beyond that, I do not know. I could also conceivable be coming from the rear end, but again I do not know. Because of the direct relationship of the noise to the speed the car is traveling, I have a strong suspicion that it comes from a wheel (or maybe a dry CV joint?) on the drivers side. I hear that rear wheel bearings are doom to change...
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I am blessed/cursed with these cars: BMW 318iS 1991 BMW 325iS 1988 Volvo 740 Turbo Wagon 1992 Quote of the week: "This chemical is known to cause Birth Defects in California." Poor Californians, they are always getting the short end of it, and now this? |
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12-25-2002, 05:13 AM
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Engine coolant circulation is dependent on engine rotation - rpm. This changes per the gear and forward speed of the car -- in gear.
What you seem to be reporting is a change in frequency dependent on the forward speed of the car independent of the rpm's of the engine. This can only be related to wheel rotation. Wheel noise is very hard to determine from inside the car. You usually have to have someone hang their head out of the windows and listen. Or drive next to you. Or put the car on a rack and spin the wheel to speed with an electric motor. Yes I would check the rear bearings. Not as bad a job as you think. Much less demanding than the later models with the single outer race for the two bearings. Biggest challenge is the large castle nut. This is torqued to over 300 foot pounds. Use a quality breaker bar with a 3 foot length of water pipe on the end to remove it. When you tighten it go as far as you can to the next through hole for the cotter pin. I've never had a stub axle strip on me even when using a 1/2" drive pneumatic impact wrench/gun. There are two bearings; a roller and a ball. The ball bearing goes on the inside. There are two lip seals and one large diameter thing cross section o-ring. Replace all of them. Also be prepared to replace the six socket head screws that hold the CV joint to the back of the stub axle.
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Hugh - So Cal 83 944 Driver Person NOT a 'real' Porsche -- Its Better!!!! When was the last time you changed your timing and balance belts and/or cam chain and tensioner? New Users please add your car's year and model to your signature line! Never break more than you fix! Last edited by SoCal Driver; 12-25-2002 at 06:42 PM.. |
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12-25-2002, 08:27 AM
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1983 Porsche 944 2.5 liter
