[73LS2]

just wondering if anyone else has run into this strange problem,I now have had a 74,75,76,78 and a 79 that all have had this weird engine like tick noise but no noises heard at the engine, this is going to sound crazy but it sounds like the ticking is coming from the rear of the car changes with rpm comes and goes while driving, it seams to go away slightly when warm,common issue with all 5 cars is exhaust system replacements and the 76,78 and 79 had rocker adjustments, any idea's really confused ? thanks

[rexs73gto]

The speedo cable can make a ticking noise that will change while driving.

[73LS2]

Originally Posted by rexs73gto

The speedo cable can make a ticking noise that will change while driving.

Im sure that is not the noise. i am aware of that one this is a very loud metallic tick and the noise is definitely coming from the back of the car,but thanks

[Bluesugar]

I'd say that your exhaust gaskets are wearing out!!

[Bluesugar]

I'd say that your exhaust gaskets are wearing out!!(the ones between the head and exhaust manifolds)

[73LS2]

Originally Posted by Bluesugar

I'd say that your exhaust gaskets are wearing out!!(the ones between the head and exhaust manifolds)

wouldn't that give me some kind of sign at the engine i.e tick and a definite leak,but i have nether at the engine ,i just don't understand whats going on here,the noise is with out any question coming from the rear of this car.

[1beautifuldaughter]

Thats a difficult thing to try to hone in on without sticking your head under it and actually hearing it yourself,,, Is it a rhythmic tick ? or is it kind of random? could it be something expanding on something on the exhaust?.Pipe close to the frame? If its with the car not moving it must be related to the exhaust in some way, or sound echoing from the front, Do you have an electric fuel pump back there?,

[73LS2]

Originally Posted by 1beautifuldaughter

Thats a difficult thing to try to hone in on without sticking your head under it and actually hearing it yourself,,, Is it a rhythmic tick ? or is it kind of random? could it be something expanding on something on the exhaust?.Pipe close to the frame? If its with the car not moving it must be related to the exhaust in some way, or sound echoing from the front, Do you have an electric fuel pump back there?,

totally understand about having the issue in front of you,actually the noise is rhythmic almost rocker/lifter type sound,car has factory fuel pump,interesting thought regarding exhaust on frame sort of a ground out condition ,this noise comes in the minute the engine is running ,tapping noise speeds up and slows down with rpm,the part that's hard to understand is why at the rear of the car ,and why so loud,I'm actually surprised no one else has experienced this problem,but thanks for your input

[1beautifuldaughter]

This is really reaching but maybe loose heat riser door in manifold slapping with broken spring, Don't even know if your car would have something like that, probably hear that under the hood . Just thinking of what could echo out in the rear. Its the unusual sounds that make you have to think of unusual problems.

[rexs73gto]

Because we can't hear it it's hard to figure it out, but have you though it may be loose baffels inside the muffler causeing it.

[th442]

My 69 Olds will tick like you are describing. Comes from the rear only when cold, it is not exhaust and is varies with rpm. Goes away quickly once car warms up. While laying underneath listening, it sounds like it is coming from the fuel line. Sounds strange I know, but can pumps tick when cold? Seems like the sound transfers down the line as I can here it all along the frame rail where the line runs, but is loudest at the rear.
Living in Tucson, it is rare that it is cold enough to occur very often, so have never pursued further diagnoses as it won't make the noise other than the coldest morning. I am still curious to the cause.

[73LS2]

Originally Posted by th442

My 69 Olds will tick like you are describing. Comes from the rear only when cold, it is not exhaust and is varies with rpm. Goes away quickly once car warms up. While laying underneath listening, it sounds like it is coming from the fuel line. Sounds strange I know, but can pumps tick when cold? Seems like the sound transfers down the line as I can here it all along the frame rail where the line runs, but is loudest at the rear.
Living in Tucson, it is rare that it is cold enough to occur very often, so have never pursued further diagnoses as it won't make the noise other than the coldest morning. I am still curious to the cause.

Wow this make the most sense if the fuel pump arm has excessive play on the eccentric its possible it could be making noise i still think you should be able to hear this from the engine compartment and also if there are rubber portions of fuel line how would this transfer all the way to the rear of the car with such crisp loud tapping does your car have a fuel line made entirely of hard tubing .thanks

[th442]

Originally Posted by 73LS2

Wow this make the most sense if the fuel pump arm has excessive play on the eccentric its possible it could be making noise i still think you should be able to hear this from the engine compartment and also if there are rubber portions of fuel line how would this transfer all the way to the rear of the car with such crisp loud tapping does your car have a fuel line made entirely of hard tubing .thanks

Good point, there is about 18" of rubber line from pump to hard line. Too warm here now to get it to do it. I probably won't hear it again till November or so.