355 Engine Noise at Start up

I have read several posts here from people who have had a noise when starting from cold which disappears after a couple of minutes when the engine warms up a little.

I too have the same problem. I would like to correct this during the winter when I plan to remove the engine for belts etc. I have eliminated the alt/wp and aircon system by removing the belts and the noise remains. I have not however removed the power steering belt.

My suspicion is the cam belt tensioner bearings but could it be something else? Someone has suggested lifters which go quiet when the oil warms a little, what is the fix for that likely to be?

Has anyone else had a similar noise and if so did they get it fixed or can anyone recognise the noise? It seems to be mentioned more by 355 owners than those with a 348. Does that point more towards lifters?

Zipped .wav sound file attached.
View attachment engnoise2.zip

 

Strange...sounds like something in the exhaust system to me (loose connection somewhere?) Or could it be the dreaded broken header?

 

Never heard that one before.

 

definitely squirrel, could be chipmunk.

 

Sounds like a bad bearing, probably on alternator which expands and tightens when heated, will probably squeal longer in the colder months.

 

I am unable to download the sound but with it being compared to a lifter noise I suspect it is a ticking sound.
With a mirror and flashlight, look closely where the air pump rails join the header. I suspect you will find a very small crack just above the weld bead on the air tube. The early headers have the outer most air rail tubes join the headers at an angle and are far more prone to this failure than the later type where all of the air rail tubes intersect the header tubes at right angles.
This very small crack will make a Ticking noise when the engine is cold and will completely go away within a min. as the headers heat up. When you locate the suspect crack, wrap a wet rag around it and start the engine when cold. You will be able to notice a change in the sound and can verify this is the source. This is a common failure that Ferrari had us reweld and is NOT the failed header issue.

Dave

 

Thanks for he comments gents.

Things seem to be pointing towards the PAS pump. The belt was very tight and when backed off the noise was considerable less, There is also approx 1mm end float on the pulley. Could not get the belt off completely due insufficient slack even with the adjuster fully loosened, looks like the pump needs unbolting. Not a great place for access.

Thanks for the info Dave re the headers, I will check that out too but my noise is more a clackerty noise than a ticking sound.

 

This is what I use for that bolt. This may be hard to find in the UK, but maybe something similar. The size you need is 13mm.


http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=78913&group_ID=18138&store=snapon-store&dir=catalog

Jay