Clicking Sound from Dashboard in 85 Caprice

I have an 85 Chevy Caprice with 343,000 miles on it ( yes 343,000) . Suddenly, I am hearing a clicking / snapping sound from the center / right of the dash during acceleration, and also sometimes during deceleration, and also when in neutral, at about 1500 rpm.

At fisrt, I thought my spark knock was coming back, but a spark knock doesn't occur in neutral, and during deceleration. So I am thinking it might be : u-joinbt... transmission... distributor... exhaust... I can't see anything unusual under the car or in the engine comapartment.

ANy ideas welcomed ! Thanks

Reply to
Lecher9000
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Is the car moving when in neutral? If yes, and you hear clicking, then the reset lever of the trip odometer could be not fully engaged-try pushing on the reset button/lever of the trip odometer and see if this changes the sound.

If no, then another possible souce of noise is the heater blower motor. A heavy duty leaf or a pine tree needle could have fallen off a tree and after landing on the windshield it slid down into the fresh air intake and got sucked into the blower motor cage where it is keeping time like a baseball card in the spokes of a bicycle-just pedal faster and it will wear out soon!

Reply to
Frank

"Lecher9000" wrote

My T-Bird made strange noises over there when the water pump was leaking and the coolant got really low. Must have been the air bubbles shooting through the heater core.

Reply to
MasterBlaster

That's interesting, because I noticed yesterday that the heater hose is leaking at the connection to the heater core tube. Going to tighten it up today and see what happens.

Reply to
Lecher9000

In neutral, the car is not moving. It's in Park, actually. And the blower is not on. The noise comes with blower on or off.

No trip odometer on this car.

Reply to
Lecher9000

I have heard the speedo click before, sometimes, but this is from the right of the speedo. And would speedometer be moving when I am in Park, revving the motor ?

Reply to
Lecher9000

Spark jumping from distributor/spark plug wire to...?

nate

Reply to
Nate Nagel

Check that rotor cap is installed correctly AND that the dist. cap is inst'd. right also. If dist. cap happens to not quite be seated, the rc may be contacting the sides of the dc. Also, look at condition of the metal 'contact' of the rb. HTH & good luck. Just my 2 cents--and often worth every dime! sdlomi

Reply to
sdlomi

Any chance this is my trans hosing up ? I have an auto trans, but this clicking is a lot like the sound I heard from a clutch in a manual trans car once, when the clutch was dying ( I think).

Reply to
Lecher9000

Yes, there is a chance it is transmission noise: if the bolts are loose that hold the flywheel to the torque converter, then the flywheel is shifting-my car came down with this illness after a trans shop rebuilt my trans; thank god you can just reach up there with a breaker bar and tighten the bolts.

Reply to
Frank

One thing to help pinpoint the source: with the parking brake on and with the car properly chocked for safety (& better with a dependable warm body inside at the controls), use a stethoscope(or a length of vacuum hose with a short piece of copper tubing inserted into the "pickup" end) to slowly wand around the underhood-area while the noise is sounding. When the sound is loudest & clearest, the source should be closest! HTH & good luck. sdlomi

Reply to
sdlomi

Hello lecher9000, Did you ever find out what was causing the noise? Write back and tell us what it was, please we are on the edge of our seats. Frank

Reply to
Frank

Frank, Nope, but I have ruled out sertain things.

Not speedo, since it makes the noise in Park, with speedo reading 0.

Not blower motor / leaf combo, since noise occurs with blower off or on.

Not electrical spark from loose wire (probably), since I see no sparks at night with hood up. (Actually should do this check again on a darker night. Wasn't really dark when I checked it).

Not distr cap and rotor. I just can't imagine the cap and rotor would be involved, since I hadn't touched them at the time the noise started. I guess it's possible, however.

What I think it might be :

Air bubbles in the heater core. But they have been there pretty long. Would have worked their way out by now, probably. I do have a coolant leak at the rear of the intake manifold, which might have become bad enough now to allow air into the coolant.

Something in the trans. The bolts you mentioned, Frank.

The "doughnut" between the exhaust manifold and the lead pipe. I think I had this click once before, on another car, and the "doughnut" gasket had to be replaced.

Heat riser or some such part / tube in the exhaust / emissions system that is rotted through and rattling.

Some other part external to stuff, which has decided to start rattling / clicking due to rust.

I am waiting for the snow on my road to melt so I can back out my TransAm from the garage, and move the Caprice in, drive it up on ramps, and have the gf rev the engine while I lie underneath looking for the source of the click . Can't do it in the driveway or the road. The ramps slip away. I need to "chock" them with 2 by 4's against the garage wall.

Will let you know what I find. And, of course any new ideas / comments are welcomed in the meantime !

Reply to
Lecher9000

Original poster here :

I used sdlomi's method with the hollow tube to locate the noise near the heater core. Thanks, sdlomi.

I then clamped off one of the heater hoses, and the noise stopped !!!! Eureka ! Thanks to MasterBlaster for mentioning air bubbles in heater core.

Now I am wondering what exactly in the heater core is making the noise. I suppose the leak is so bad at the intake manifold and / or freeze plugs that I have a constant flow of air through the system, which never bubbles out through the rad cap.

Am thinking of dumping in some BarsLeak to seal it all up. Problem is that stuff makes the car overheat in summer.

Or I could shell out the $ to have the intake manifold replaced. ( on an ancient car with 353,000 miles.

Do you guys think it is air bublles shooting through the heater core, or something else about the heater core making the noise ?

Thanks,

L
Reply to
Lecher9000

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