C5 Tourer 163Bhp Start V Noisy, Next Start Perfect

[MartinKat]

Happened once today and once about 2 months ago.

Started engine: extremely rattly (sounded very serious). Turned off immediately. Started again - running perfectly.

Purchased 6 months ago. Has now done 90K. Superb car. Fast, quiet, smooth, comfortable, This is the only 'fault'. Everything else works perfectly.

Any ideas?

[paul.h]

Welcome to the forum.

 

When was the engine oil and filter last changed and was the correct oil used, is the oil level correct when checked with the dip stick ? First thoughts are it could be the hydraulic tappets/valve clearances and the oil pressure is slow to build up.

[MartinKat]

Servicing is up to date.

The noise was very loud - uneven rattling, It sounded so serious that I only let the engine run for a few seconds. During those few (5?) seconds the noise did not alter.

During my 6 months owning the car including  -10C in the Alpes, it has always started perfectly and from the instant it starts the engine is really smooth.

The only other time was when I nearly stalled the engine (reversing full lock) but instead of stalling, a similar situation occured. Switched off, re-start, perfect. At that time I seem to remember that it sounded as if the engine was running noisly on 2 cylinders. My thought was that the processor was confused about what it was trying to do. Switching off re-booted it's function.

Very strange!

 

 

[paul.h]

'Servicing is up to date.'

 

How many miles ago was this for the oil/filter change and have you checked the level with the dipstcik, just in case the level sensor is faulty ?

[Johndouglas]

If your engine hasn't had new engine oil and a new filter whilst it's been in your ownership, I would do it before trying anything else.

[Randombloke]

Could be the DMF. Do you get the engine oil level correct advice on switch on?