Howling sound?
08-22-2002, 10:05 PM
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Howling sound?
Hey guys,
I need your advice. I am getting worried about this howling sound which increases and decreases with my speed. I am thinking it may be the tires. I just put on brand new 16' Kumhos all around 2 weeks ago, due to one blow out on the highway caused by dry rot. The tire guy told me one of the rims was slightly bent on the inside, but is okay. I am thinking the bend on this rim may be due to the blow out. Could this possibly cause the howling sound? Thanks in advance.
Ed
85 928s Auto
I need your advice. I am getting worried about this howling sound which increases and decreases with my speed. I am thinking it may be the tires. I just put on brand new 16' Kumhos all around 2 weeks ago, due to one blow out on the highway caused by dry rot. The tire guy told me one of the rims was slightly bent on the inside, but is okay. I am thinking the bend on this rim may be due to the blow out. Could this possibly cause the howling sound? Thanks in advance.
Ed
85 928s Auto
08-23-2002, 01:40 AM
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Hi Donald,
Yeah, I am pretty sure it isn't engine speed because I revved in park to make sure it wasn't. Also, I mashed the throttle up to about 80. The engine seems to drown the sound out a little bit at throttle, but when I let up, you can hear the howl. It decreases as the speed decreases. Is it possible for a bent rim to be making all this howling. I can only suspect the tires because I didn't experience this before replacement. I wonder if tire balancing has anything to do with it? Thanks in advance.
Ed
85 928s Auto
Yeah, I am pretty sure it isn't engine speed because I revved in park to make sure it wasn't. Also, I mashed the throttle up to about 80. The engine seems to drown the sound out a little bit at throttle, but when I let up, you can hear the howl. It decreases as the speed decreases. Is it possible for a bent rim to be making all this howling. I can only suspect the tires because I didn't experience this before replacement. I wonder if tire balancing has anything to do with it? Thanks in advance.
Ed
85 928s Auto
08-23-2002, 02:13 AM
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No, I don't see how balance would do it, but a delaminated tire would. You should have the tires checked as they are new.
I recently had a howling from the engine due to my five thumbs when I was in there doing vacuum lines (didn't get the crankcase breather hose on quite right).
Good luck
Donald
I recently had a howling from the engine due to my five thumbs when I was in there doing vacuum lines (didn't get the crankcase breather hose on quite right).
Good luck
Donald
08-23-2002, 02:57 AM
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Donald,
Thanks for your prompt responses. I will have my tires checked out again this weekend. Hopefully that's what it is. I also forgot to mention that I had it aligned there as well. Anyway, thanks again.
Ed
85 928s Auto
Thanks for your prompt responses. I will have my tires checked out again this weekend. Hopefully that's what it is. I also forgot to mention that I had it aligned there as well. Anyway, thanks again.
Ed
85 928s Auto
08-23-2002, 10:32 PM
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Easy to check and rule out road noise (tire) vs. mechanical by raising rear and running at highway speed. I've used this to diagnose rear wheel bearings and check rear vibrations.
Set car on stable platform with wheels just off ground. While I've used jackstands before, I like 2x12/cinderblock sandwich better for stability and jacking point protection.
You can also check for wheel & tire roundness easily while up. Check inside wheel lips if concerned for roundness, as most bent rims will show up on unreinforced inside, while appearing round outside.
Try first with wheels on, then off. You'll be surprised at all you can learn, diagnose, and rule-out spending an hour at this. Good luck,
Jeff
87 5-spd
RMB, chips
easily bent 993 MM aftermarket wheels
Set car on stable platform with wheels just off ground. While I've used jackstands before, I like 2x12/cinderblock sandwich better for stability and jacking point protection.
You can also check for wheel & tire roundness easily while up. Check inside wheel lips if concerned for roundness, as most bent rims will show up on unreinforced inside, while appearing round outside.
Try first with wheels on, then off. You'll be surprised at all you can learn, diagnose, and rule-out spending an hour at this. Good luck,
Jeff
87 5-spd
RMB, chips
easily bent 993 MM aftermarket wheels
08-24-2002, 12:08 AM
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I'd rule bad tires or wheel bearings. Our 928 did the same thing, not to mention had a real bad rear shudder at 80 mph. When we looked at the rear tires, the inner walls had the steal splines showing...worst yet i hit 110 with the tires like that too 
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08-24-2002, 02:09 AM
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Hey guys,
I just thought I'd mention that on my receipt for the new Kumhos, I noticed the clerk wrote down that there is some play in the front wheel bearing. Could this be the cause of the noise of the droning/howling noise? I figured I'd try to ask before I talk to the tire people. Also, if it is, do you guys think it is something the tire people can competently take care of? Or should I just take it to my porsche mechanic? I have been pretty annoyed with the noise and will express that to the tire people as it never occurred before I replaced them. I'll let you guys know what happens. Thanks again.
Ed
85 928s Auto
I just thought I'd mention that on my receipt for the new Kumhos, I noticed the clerk wrote down that there is some play in the front wheel bearing. Could this be the cause of the noise of the droning/howling noise? I figured I'd try to ask before I talk to the tire people. Also, if it is, do you guys think it is something the tire people can competently take care of? Or should I just take it to my porsche mechanic? I have been pretty annoyed with the noise and will express that to the tire people as it never occurred before I replaced them. I'll let you guys know what happens. Thanks again.
Ed
85 928s Auto
08-24-2002, 02:51 AM
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I would have the tires checked, and you should check the front bearings. You can jack up the fronts and give it the wobble test same as any rear wheel drive auto, here's a good description:
<a href="http://www.928oc.org/tip/tip235.htm" target="_blank">http://www.928oc.org/tip/tip235.htm</a>
and here are the pictures:
<a href="http://sis125.berkeley.edu/928.html" target="_blank">http://sis125.berkeley.edu/928.html</a>
"mechanical Info", "Wheel Bearings"
Front bearings are easy stuff. I wouldn't pay a Porsche mechanic for this nor trust the tire store (no offense to any employees of tire stores). But I find it hard to believe a mildly loose bearing would howl unless it had no grease left in it or was really loose at some point for a good while- however it will wear the tire unevely and gradually destroy the bearing.
Donald
<a href="http://www.928oc.org/tip/tip235.htm" target="_blank">http://www.928oc.org/tip/tip235.htm</a>
and here are the pictures:
<a href="http://sis125.berkeley.edu/928.html" target="_blank">http://sis125.berkeley.edu/928.html</a>
"mechanical Info", "Wheel Bearings"
Front bearings are easy stuff. I wouldn't pay a Porsche mechanic for this nor trust the tire store (no offense to any employees of tire stores). But I find it hard to believe a mildly loose bearing would howl unless it had no grease left in it or was really loose at some point for a good while- however it will wear the tire unevely and gradually destroy the bearing.
Donald
