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Join Date: Dec 2020
Posts: 5
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1975 911s Engine Noise / Knocking
My 1975 911s just developed a knocking sound in the engine and I wondered if anyone had any experience with something similar. I posted a short video to YouTube. Thank you in advance! https://youtu.be/bRuPsjt_Nu4
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12-13-2020, 12:39 PM
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Could be caused by several things. I'd start with draining oil and looking for metallic chunks. Then remove the valve covers on that side and see if rocker arms are intact and verify valves are moving. Roll engine by hand to see if there is a "clunk" at any specific point of rotation.
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12-13-2020, 07:29 PM
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as fana ..said..any other story ..low on oil perhaps??
Sounds like a rod bearing is kaput..But you will see when you drain the oil Ivan
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1985 911 with original 501 761 miles...807 506 km "The difference between genius and stupidity is that, genius has its limits". Albert Einstein. |
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12-14-2020, 01:59 AM
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Still here
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Doesn't sound like valve noise.
Good luck with the diagnosis. |
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12-14-2020, 01:47 PM
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Join Date: Aug 2020
Location: SoCal
Posts: 20
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maybe unplug the plug wires one at a time while running, see if the noise changes, sounds like a rod bearing to me
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12-14-2020, 02:02 PM
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Reiver
Join Date: Nov 2011
Posts: 57,457
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How many miles on the engine.... and is that a mag eng. ?
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De Oppresso Liber Strength and Honor 5th Legion |
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12-14-2020, 02:07 PM
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Thank you for all the replies. The engine has about 70k miles on it and I am the 2nd owner since 1984. Leaks a fair bit of oil but level and pressure are fine.
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12-20-2020, 06:56 AM
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Reiver
Join Date: Nov 2011
Posts: 57,457
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I'd tow/take it to a pro Porsche shop for an eval. If it is rod knock you don't want to drive it.
Most normal noises diminish as the car warms up to normal...valves etc. Rod knock gets louder. You can still have good oil pressure if you have bearing failure but the oil temp will rise.....
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De Oppresso Liber Strength and Honor 5th Legion Last edited by Reiver; 12-20-2020 at 08:35 AM.. |
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12-20-2020, 08:30 AM
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The engine has been running hotter (north of 220) but I drive it so little at a time I didn’t think much of it. Appreciate the help and will get it towed and looked at ASAP
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12-20-2020, 08:52 AM
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Black Label
