NOISY 997T ENGINE ON COLD START UP

[elvis]

Just had a major service including spark plugs of my 997T.
Since its been serviced on a cold start Ive noticed the engine is really rattly for about 2-3 seconds then it settles down and normal noise.
The noise is like a mechanical rattle for a few seconds almost like something is running dry until oil gets there then its quietens to normal.
The car has done 35K and didn't do it prior to service and the noise is not nice noise.

Is this something anybody has experience of? And can help with?

The Porsche centre are at the moment stating they don't know how it could be linked to the service....

 

[Red993C4]

Just had a major service including spark plugs of my 997T.
Since its been serviced on a cold start Ive noticed the engine is really rattly for about 2-3 seconds then it settles down and normal noise.
The noise is like a mechanical rattle for a few seconds almost like something is running dry until oil gets there then its quietens to normal.
The car has done 35K and didn't do it prior to service and the noise is not nice noise.

Is this something anybody has experience of? And can help with?

The Porsche centre are at the moment stating they don't know how it could be linked to the service....

To start at the bottom: In the OPC's position, I'd also be at a loss to know how changing oil, air filter and spark plugs would cause an engine suddenly to be more inclined to rattle on cold starts (beyond the first start when drained hydraulic valve play adjusters might need to fill up with oil again, and assuming the same grade of oil was used before and after the service).

Reading your post, it does sound as if you may have put the OPC on the defensive by drawing a link between the service and the new issue, rather than finding out first what might the technical cause of the perceived issue? :dont know:

 

[elvis]

Ive only had the car 6 months so not sure what oil was in but I assume it was the same grade.

The only possible link is I believe when changing spark plugs they remove the rear bumper and drop the engine and wondered if a breather pipe or something similar has got trapped on re securing the engine??

 

[infrasilver]

If they didn't use the same grade oil as was previously in, this may cause a rattle on start up which I'm assuming would be the timing chains as this is common on many multi chain high performance engines. The oil drips off the chains and quicker than previously so it takes a second for the chains to pick oil up again. Chain guides wear and make things a little slacker.

I don't want to worry you and may be blowing this out of all proportion (as it might not even be the chain) but this is one of the weaknesses if found out about on the Turbo when I was investigating my own N/A 996 chain failure. I found more Turbo chain failures than the normal 996 failures, still vary rare though.

 

[Martian]

The engine isn't 'dropped' for a plug change on a Turbo although a lot of stuff is removed to access them.

 

[Red993C4]

If they didn't use the same grade oil as was previously in, this may cause a rattle on start up which I'm assuming would be the timing chains as this is common on many multi chain high performance engines. The oil drips off the chains and quicker than previously so it takes a second for the chains to pick oil up again. Chain guides wear and make things a little slacker.

I don't want to worry you and may be blowing this out of all proportion (as it might not even be the chain) but this is one of the weaknesses if found out about on the Turbo when I was investigating my own N/A 996 chain failure. I found more Turbo chain failures than the normal 996 failures, still vary rare though.

The Turbo's chain drive has two hydraulic chain tensioners, pressurised by the engines lubrication circuit. The rattle on start-up will be due to these tensioners needing to be "re-charged", not to oil having dripped off the chain links.
If the new oil were to be a lower viscosity than the old, it could result in more leakage from the tensioners during standstill? :dont know:

 

[Roadrunner996]

Does the car have a full OPC service history as per the service book ?
If so, do you also have any bills showing oil changes performed at an indie 'between' OPC services (no stamp in the book as buyers don't like those.....). Perhaps the engine was running with 'thicker' oil before the OPC drained it and filled the car with Porsche Approved oil / Mobil One (because thats what it says to do in the service manual :frustrated: )