Mysterious Ticking Noise

mconnelley · 10-13-2009, 12:49 AM

Hello:

I have a '65 Mustang with a 1974 302 engine. When I drive the car, I hear a ticking noise coming from in front of me. The frequency of the ticks is proportional to the engine RPMs, and I get the ticking even when the car is stopped. I seem to have to drive the car to get the ticking noise, and haven't heard it when I just start the engine briefly in the garage. I once had the car out for a drive, heard the ticking noise, and drove it home to listen to the noise with the hood open. With the hood open, it sounded like someone tapping the end of a screw driver on the bottom of an empty tin can, or as if there was a little man inside my valve covers with a little hammer, trying to break out. Another interesting feature of this noise is that the noise suddenly and completely goes away when I'm driving every few minutes. After the noise goes away, it'll be quiet for a minute, then you slowly hear the noise build up, then it'll go away again. So, any suggestions as to the nature of the problem?

Cheers
Mike Connelley

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MonsterBilly · 10-13-2009, 03:05 AM

Have you checked your oil lately? ;ow oil may cause this, or you may need a valve adjustment.

Carlos Pineiro · 10-13-2009, 04:25 AM

Auto transmission? Tranny come with the 74 engine, or orig or other?

When you hear the ticking, see if the tone changes or stops if you step on the brake and shift through the gears. If so, it could be the flex plate tapping the bell housing. A valve tapping is more likely in general to be a tapping sound. Could it be the fan tapping the shroud? As shroud bolts vibrate loose over time, the shroud will shift a bit and cause this. It could be a number of things including bad gasoline. Let us know. Good luck.

CP

tx65coupe · 10-13-2009, 04:49 AM

It might be a sticking lifter or an just exhaust leak.

I agree about checking the oil.

I would recommend getting a mechanic's stethoscope. They are inexpsive and can be very helpful.

This is the one I have. Its only 10 bucks.

http://www.jcwhitney.com/Automotive_...;N;2017895;0;0

Sometimes auto parts store have them.

kalli · 10-13-2009, 04:58 AM

the most common tapping noise are misadjusted lifters and leaking exhaust gaskets.
i didn't believe that an exhaust gasket could sound like valvetrain noise until I had that on mine. check for that

hammerit · 10-13-2009, 12:36 PM

I had what I thought was lifter noise....turned out to be loose spark plugs. Hope your as lucky.

Oxnard Montalvo · 10-13-2009, 03:32 PM

While nice, you don't need no fancy pants stethoscope. You can find the location of many underhood noises with a wooden dowel, large screwdriver or any long thin solid object. Place one end against the suspected area and the other end to your ear. It's easy to pinpoint the sound.

hiboostwoody · 10-14-2009, 01:09 AM

Don't forget about a sloppy timing chain slapping against the cover. I have also seen a mechanical fuel pump that would make that noise when the pump arm would move up and down.

JoelEsler · 10-14-2009, 08:29 AM

Usually an exhaust leak will sound deep. I had one when I first bought my car, it wasn't so much a ticking as it was, like, well, like you said, some dude in the car trying to get his way out with a miniature sledgehammer. The sounds is deep though. (Not "tin-y", as in tin, the metal)

mconnelley · 10-16-2009, 03:25 AM

Hello:

To answer a few questions, the car has an automatic 3 speed transmission, but I don't know if it's original to this car or this engine. The oil and transmission fluid levels are right where they should be, but I don't know if the oil pressure is correct (I just have the dummy light on the dash, which could have failed). The the origin of the noise was something like a leaky exhaust gasket, then I would expect that the noise would be constant. This noise tends to last for a few minutes, suddenly go away, slowly get louder, then go away again. I'll work a bit harder to isolate the location of the noise, either with a stethoscope, a screwdriver, length of rubber hose, etc. The sound I hear definitely sounds tinny to me, not a deeper sound. I watched a few clips on youtube of leaky exhaust gasket noises, and I think the sound I have sounds tinnier than what I heard there. Thank you all very much for you help and advice.

Cheers
Mike Connelley