Tapping On Start Up

[bill smith]

Don't know whether anyone else has come across this before, but on my 99 996 C4 (3.4) I get a light tapping noise on start up, a bit like a noisy tappet. This noise goes after approx 5 to 10 seconds, and is more prominent when the car hasn't been run for a couple of days.

My OPC thought it was the cam chain tensioners and replaced those under warranty, but this didn't cure the fault. The car is now booked in again for further investigative work. It sounds like a lazy hydraulic tappet to me, which are fortunately covered by the warranty.

The car has just had a 24,000 mile service, and so the car has recently had some fresh Mobil 1 (0W40) oil in it.

Anyone else had this problem and solved it?

Any help or advice would be appreciated

Bill

[Loren]

Normal. Those are your hydraulic lifters - all the oil drains out of them when the car sits for several days.

If you start the car every day you likely will not hear that.

[phillipj]

I have a 99 996 as well. Mine does the same exact thing. The sound goes away after about 10 or 15 seconds. Like Loren said this is normal and nothing to be concerned about.

Phillipj

[phillipj]

I have a 99 996 as well. Mine does the same exact thing. The sound goes away after about 10 or 15 seconds. Like Loren said this is normal and nothing to be concerned about.

Phillipj

[1999Porsche911]

I have a 99 C2 and I DO NOT have tapping at start up even after sitting for 2 weeks. However, the only time I use Mobil 0W40 is to oil the hinges on the doors. :)

[bill smith]

Thanks for the advice - I did wonder whether I was being paranoid. When the car is hot and running it sounds fine.

I suppose there's no harm in letting the OPC have a look at it if the work's covered by the warranty - so I'll see whta they come back with.

If the work's not covered then I'll leave it unless it gets worse.

btw Do you guys all run on Mobil 1 (0W40) in the US?

[Tool Pants]

My guess as to a reason why Porsche switched to 0W-40 was because of all the lifter noise complaints on cold start-up.

[sir16]

i use 5w30 mobil,and no problem,im close to 100 000miles.little noisy,at idle ,but it looks like the injectors .

Edited October 8, 2007 by sir16

[tac27]

I have a similiar experience with my '03 996; just a few seconds after start up and then into the 'normal' engine sound. During the very hottest days of the summer it last longer, perhaps as long as a minute; both the dealer and two indie mechanics provided the same answer as Loren's.

I use the Mobile 1 0 W 40. The car is a daily driver, approximately 35 miles a day in the furnace known as Las Vegas.

[White987S]

I use Red Line 5W40. Full synthetic. Love it. Great oil. Expensive- $9/qrt. Car sat for 5.5 months during winter storage. At first start-up, car sounded like it had been pre-warmed.

I drive it about once a week, 350-450 miles in that one day, all at once!