This is about my daily driver. The GTA is in the garage in all this snow lately.

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
Park, at about 1500 rpm. The noise comes and goes, but usually it is there during high end of the gear during accleration. Sometimes not there at all, even while accelerarting. It's an unevenly spaced click / snap sound, like a spark knock.

At first, 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-joint... transmission... distributor... exhaust... or speedo (but would speedo click in Park?)

It happens with and without the heater fan on.

I can't see anything unusual under the car or in the engine compartment. Have not been able to drive it up on ramps yet to get a good look.

It started 2 days ago, out of the blue, and is about the same as it was 2 days ago.

Sounds like it is coming from the dash, but I guess it could be from the trans hump too.

I hope it's not the trans.

ANy ideas welcomed ! Thanks

 

Sounds like an exhaust leak to me. Mine has one too. It sounds louder at times depending on wether the car is in open or closed loop. Usually in the mornings when I drive off and the car is still in open loop the ticking is very noticeable, also during acceleration. When the car is in closed loop it will not tick under light acceleration, but under hard acceleration it will tick like crazy. And yes it is at an even and steady rate.

Ozzy

 

I think it might be air trapped in the heater core. I put my hand on the heater box (after I removed the glove compartment) and felt some rattling there while the noise was happenning. The noise is a lot like an old steam radiator snapping in a house. I wonder how long til the air bubbles work their way out, if that's what it is. I had a coolant leak at one of the heater hoses a couple days ago, and I tightened it up.

 

I think it's mice, and you're scaring them when you floor it! lol

I would also guess exhaust leak

 

Mice, yes could be ! After spending hours checking all sorts of stuff under the car, I finally found something useful. I clamped off one of the heater hoses, and the clicking sound doesn't happen any more. :lala:
Now I just have to figure out why the heater core is clicking. I have a coolant leak at the rear of the intake manifold, and I guess air could be getting into the system there. Or maybe I just have to open up one of the hoses at the core, fill it with antifreeze, to get rid of the air. Just need to get some time to do it !

 

Only 343,000 miles? Maybe next time you can get a "solid, durable" car like a Honda or Toyota. Comsumer Reports says they're the best. Of course, they're the same people who in 1987 called the Plymouth Reliant K a "best value". There goes their credibility. Then again, they are journalists, not engineers.

The noise could just be thermal expansion and contraction of the heater core, or the plastic case enclosing the core. After 19 years and a trip to the moon and back, a few rattles can be expected. Just think - If you had a Honda, you wouldn't have those problems. You would have had to scrap what was left of it after 180,000 miles. The carbed 305 just keeps goining and going, like the Eveready bunny. Must be no good....