Resonant Rattle

Mulletwagon

Mulletwagon

Well-known member
At about 45 mph I get a low pitch rattle, more like a loud growl, that comes and goes. Sounds like a bad water pump bearing, but a new pump did not fix the problem. Can't find any loose panels or worn suspension joints that could be vibrating. Wondering if it may be timing gear related. Previous owner contracted a high dollar rebuild so suspect a worn engine component is not likely. Engine has about 1500 miles since rebuild. Welcome theories.
 
Mulletwagon said:
At about 45 mph I get a low pitch rattle, more like a loud growl, that comes and goes. Sounds like a bad water pump bearing, but a new pump did not fix the problem. Can't find any loose panels or worn suspension joints that could be vibrating. Wondering if it may be timing gear related. Previous owner contracted a high dollar rebuild so suspect a worn engine component is not likely. Engine has about 1500 miles since rebuild. Welcome theories.
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I feel your pain... my car has several of these "sympathetic vibrations". One that I posted about earlier has seemingly gone away on its own (worrying). The others I think are the brake rods, muffler baffles, and choke rod. Maybe this will give you something to work with.
 
I keep complaining about rattles and squeaks and my wife tells me to "chill out". She likes it and says it is part of the character of a 90 year-old car.
 
Do you have the 2-piece swing-out hood supports on the car?

My Dad has them on his car and if you swing them in all the way, so that the moving part touches the fixed part, they will tap each other and make a lot of noise. Easy to fix, just lift the moving part up 1/2" before closing the hood.
 
If your car has engine pans, a broken attachment ear can vibrate badly and make a lot of noise. Happened on mine...2 were broken.....fixed them and no more noise.
 
Does it do it in any other gear or sitting still at a certain RPM?

Last time mine did this it was loose exhaust also, BUT, the exhaust was loose because the bolts holding the motor mount to the passenger frame rail were loose. Well, the one that was left was loose.

The noise had me convinced I was going to be putting bearings in the transmission, and I had actually crawled under to check the oil in the trans when I found everything loose.

Sent from my E6810 using Tapatalk
 
My engine pans crack on the drivers side oil pan bolt. It has broken twice in 20 years. What a loud noise it gives off, you can hear me coming from a block away:eek: So l always wondered how much flex are these cars are supposed to have:confused:
 
My choke rod was vibrating against the throttle rod at 35 and 45 mph and when the engine decelerated during shifting. Noticed a shiny spot on the choke rod. Immediately recognized it be the source of my last annoying rattle.
 
Sure sounds like what the guys have already said. Get a rubber mallet and lightly hit the hood props, the radiator to dash rods, those engine pans and the windshield frame, and it should show itself.
 
I have a resonant rattle that comes when I back up into my parking spot. I suspect the brake rods vibrating. I plan "someday" to take some inner-tube strips and use them to pull lightly on the rods and tie them off to the frame. Hopefully I can locate the culprit that way.
 
Do a bolt check. Fenders,headlight bar,windshield, gas tank clamps,floor boards. If it has a fastner,it could rattle. When rattle starts touch the brake pedal,see if it goes away. Also a click or two on the parking brake.
Wick
 
A harmonic balancer pulley may solve your problem if it's an engine related vibration or timing gear rattle? As far as I'm concerned it's a miracle device and such a simple solution.
 
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