Re: Ticking

The first is a rapid ticking sound that doesn't change with engine speed. I've hear it over my left shoulder twice recently, but not consecutive times. It's about three times as fast as a watch ticking that doesn't change with engine speed. The other is more faint like a white noise or the sound of a fan blowing. That sound does change with speed of the engine. Neither has caused the CEL or other warnings to appear on the OBC screen. Haven't really pushed the car, but I haven't noticed any power loss under commuting situations as I have not pushed the car recently. I'm going to bring it in to the shop but thought I'd check here first to see if I'm only parinoid or if there could be an issue(s).

Does the ticking only happen when you're driving? Does it change with wheel speed? It could be a rock in one of the tires. If it doesn't happen when the car isn't moving it's likely related to one of the rotational parts of the car.

thanks. It ticks when at idle and does not change with speed. I find that very odd. If I were paranoid, I'd be thinking bomb under the car.

Quote
db997S
thanks. It ticks when at idle and does not change with speed. I find that very odd. If I were paranoid, I'd be thinking bomb under the car.

Does it happen with engine at operating temperature? When first warming up or cooling down, the exhaust sytem can make a ticking sound as the metal is expanding / contracting.

Cold. I have only a 4 mi commute.

Although you're hearing it from the left: Is the driver's, but not passenger's window open? And/or top down? Just thinking something is caught in the engine compartment ventilation fan, on the right side only, and acoustics are playing tricks with your directional perception.

either a cabin vent fan or some other fan that runs all the time.

Since noises are notoriously hard to pinpoint I'd hazard a guess the noise is coming from one of the radiator fans. You can I think check this out by starting the engine and upon hearing the noise determine if the A/C is on. If it is then turn it off and stop the cabin vent fan. If the noise goes away well there you are.

If the noise doesn't go away the noise is coming from some other source. I do not think the engine compartment vent fan runs all the time. If it does then that's a candidate source for the noise.

Another possible source for the noise would be the cabin fan that runs to circulate air over an inside temperature sensor. In my car there is supposed to be a small fan behind the circular grill on the dash over on the passenger side of the car. This fan circulates cabin air over the temperature sensor to keep close tabs on the cabin air temperature so the climate control system can keep the cabin temperature at the desired setting temperature.

There is another possible explanation, way out there though, and that is there is a relay acting up. Once in awhile, my 996 makes a rapid clicking noise when I turn on the key and start the engine. The noise is clearly present though before I even turn the key from on to start. The clicking doesn't last long, under a minute (and probably under a half a minute) though the duration seems longer than that.

I mentioned this to a tech and he offered the idea it was coming from a relay. Nothing's failed yet and the noise is not present all the time and I have not found a need to have this diagnosed.

At lunch today, I was finally able to take the car in for a tech to look at it. The head service tech took the car and me out for a spin--what a great job he has. He did hear the white noise I was talking about, but didn't know what it was or if it might be normal on a pdk 997. He really put the car through the paces and thought everything seemed normal--power, upshifts, downshifts, engine sound, etc. I'm just going to keep an eye and ear on things and see how it progresses. With the car idling when we got back to the shop, he ever so slightly loosened the oil cap and we immediately heard the same white noise, but the engine speed also increased noticably. Alast, that was not the issue, but odd how the sound was similar while the engine reaction was not. It made me think, though, it's been a while since I really stretched her legs. With the warm weather coming, it's a sign that I need to hit the twisties and let that engine growl.

Thanks all for the input.