For today’s tech tip, we want to share Mike Dawson’s “Noises From The Rear” which was published in the PCCA May 2026 Newsletter. To learn more about the PCCA chapter, click here. While it’s important to learn to diagnose a problem that may come up with your Corvair, it is equally (more?) important to be able to recognize an issue before it turns into a problem. Thanks to Mike for putting together this helpful list and thanks to PCCA for publishing it!
This month will be an attempt to help diagnose noises from the rear of the car. Drive train noises also apply to FC vehicles.
• A rolling noise that does not change in pitch from acceleration to deceleration in the same speed range is usually a wheel bearing. Wheel bearings on early models usually squeak or make a cycling growl. Late bearings will squeak, make a raspy noise or howl.
• A clank when starting from a stop or going into gear may be a U-joint. They can also make a clinking noise, usually at low speed. Loose axle yokes on early models and FC can make the same noise.
• Howling that changes noticeably between acceleration and deceleration is either a worn out pinion gear, mismatched ring and pinion gear or very loose or worn out pinion bearings.
• Thunking noises on late models can be either the top or bottom shock mount. Check for shifted lower bushings or rusted top mounting pads. The latter can be repaired.
• Squeaking from one side of a late model going over bumps can be a trailing arm bushing that has popped out of its shell. The arm is rubbing on the bracket and the tire is way out of toe alignment.
• A heavy thump or clunk going over a quick rise may be a separated motor mount on a 1965 model. The other models make less noticeable noises unless almost terminal. Best to check them every time you change oil filters if they are original.
• A loud squawk that occurs briefly as you push in or release the clutch is a pilot bushing problem. Always replace it any time the transaxle is separated as they take a set very quickly.
• A knocking noise at idle which disappears or gets quieter when depressing the clutch is a flywheel with loose rivets (all years, all models of manual transmissions).
• A squeal or light rattling noise that is only noticed when holding down on the clutch pedal is a clutch release (throwout) bearing.
• A moaning sound that is heard only when the engine is cold is probably a late model blower bearing that needs greasing or replacing. Early model bearings usually start a continuous metallic rumbling noise due to their design.
• A light to heavy tapping noise that goes away after driving is usually a lifter that has lost its oil temporarily. Long storage or cold startups and quick shutdowns cause lifters to go “flat”. Frequent oil changes and avoiding a lot of start ups without driving helps this problem. Age and sometimes dirt interfere with lifter check valve action.
• A lighter tapping noise that sounds like a lifter may be a bad exhaust valve guide. The exhaust gas blowing down the guide sounds almost metallic.
• A persistent squeak (usually powerglide cars) that only occurs at a stop, in gear with your foot on the brake may be the rear parking brake cable at its support brackets or on the backing plate on the inside of the brake drum. To test this theory, pull slightly on the parking brake handle when the squeak occurs. If it stops, you have found the problem. The idling engine gently tugs on the spring attached to the cable assembly: install the missing clips on the two support brackets, grease them and use brake lube under the cable inside the brake drum.
• A chirping from the engine that is noticeable only on acceleration may be a loose head. Retorque the heads immediately or you will have blown head gaskets. This is usually caused by overheating and can sometimes result in studs pulled out of the crankcase. You can also get a bad smell in the heater since combustion gas is escaping.
• An actual blown (burned through) head gasket will make a persistent spit-spit-spit noise as the engine idles. The noise will get louder under a load and bad fumes get in the heater.
• A mild howling from four speed transmissions up through 1965 that is only heard in first, second and third is probably the needle bearings and shaft in the counter gear. The noise is gone in fourth gear since the counter gear is not loaded. A common problem and the parts are available.
• A clicking noise from the rear of early models & FC at very slow speed may be the brake shoes snapping across backing plate pads as they try to follow an out of round drum or a slightly bent axle (common problem). Apply brake lube to the pads or correct the problem. This can also be a bad U-joint or a badly worn stub axle that is rocking the side gear of the differential.
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