Ticking cold start noise

[toddel68]

Hi, I recently get a ticking noise about 30 seconds after a cold start of the engine which resembles the knocking noise of an old diesel engine although not as loud. Most of time it's tick-tick-tick with about o.2s pause in between the ticks and then again after 5s or so tick-tick-tick again . After that everything is normal.I'll try to link a (bad quality) sound file I've recorded. The file gives a wrong impression about the volume of the ticks though. It's not as loud as it seems.The whole thing lasts about 30s.

The car is a 99 C4 with 78300km on the clock. I already had my 80000km inspection done 2 weeks ago with oil change from Mobil1 0W-40 to 5W-50 done by myself last week. I only noticed the noise after I had already done the oil change. Should have noticed the sound if it would have been there earlier because I usually drive the car out the garage and then walk around it to load my luggage on the rear seats setting off to work. If have no idea though why the oil change or the inspection should be a cause.(Oil level is fine)

Any thoughts?

Thorsten

porsche.wav

Edited November 8, 2006 by toddel68

[Bryan]

Thorsten: did you find the cause?

[White987S]

I bet if you go back to the 0W40 oil, the ticking noise may deminish.

[Scouser]

I bet if you go back to the 0W40 oil, the ticking noise may deminish.

My car does exactly the same and its common for the 996 to be a bit clackety at start up especially if its been left long and/or in cold temperatures. But that does sound a tiny bit louder than mine although exactly the same. White987S is right. The oil viscosity in 5W50 is thicker than 0W40 so when you start your car the oil will take a little longer to coat everything again. Go back to 0w40 and my guess it will go away or at least be a bit quieter.

[wvicary]

I agree it does sound like valve train noise. Go back to 0w40 and let us know the results.

[toddel68]

Sorry it took me quite a while to give some feedback but I wanted to make sure that my engine is in a stable state now. For several weeks now I haven't heard anything from the engine and even after a final 'test' with the car resting for two weeks at temps around freezing point there was no ticking.

So the conclusion seems to be that the engine needed some break in time with the 5w-50 oil. (I wish I could offer a mor logical explanation).

Overal I'd say the engine is running much smoother now when idling warm. But that might just be an illusion and certainly not enough reason to start the great oil debate. :D

Thorsten