Questions and Answers

Cadillac Going Tinkle Q. My girlfriend owns a 1978 Cadillac Coupe DeVille, carbureted, 425 engine, with 175,000 miles on it. It has P/S, A/C, and no ABS, automatic transmission. Upon acceleration and even at idle when first turning on the car, you will here a tinking/metal like sound coming from the right side of the motor.

We have had a couple different mechanics attempt to look at it, however they couldn't diagnose without cracking it open (cost is more than we can handle), so we haven't had them open it up yet. At higher speeds (40+) this sound completely disappears, but reappears after stopping and accelerating again.

This sound is unlike much I have ever heard during inspecting a vehicle, and I don't know what this could be. Lifters, valves, rings, shards from the head? I am at a total loss, and since we've had a full tune up, oil change, new rear end, new brakes, new cat, new water pump, new fuel pump, new radiator, rebuilt transmission and brand new carburetor, I feel like were about to lose 2000+ dollars worth of repairs, due to something randomly wrong in the engine.

Please, if you have any good news or know where someone in metro Portland,OR could get this done for cheap, and you can diagnose this somewhat, it would put a smile on my face.

Thank you...

A. I don't know how much help I can be to you. I can't hear the noise for myself and that makes it very difficult to try and suggest possibilities.

I can make a couple of suggestions to eliminate possibilities. At least that will get you closer to what the problem is. If the sound is like marbles in a can, I would check the ignition timing. Make sure there is vacuum to the vacuum advance at idle and look inside the distributor and make sure the centrifugal advance weights move freely and not rusted up.

Other than that, I don't know. Lifter noise is fairly distinctive and an experienced mechanic would pick up on it right away. The same with noise from the bottom end. Somehow I have a hunch it is ignition related rather than mechanical.

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