Rattle at start up - 355

I have a 95 355 spider, low miles (12K) and recently immediately after start up I hear a metallic rattle coming from the engine bay. After about 5 minutes driving it stops and doesn't come back.
Wondering if it could be the cat insides degrading and rattling until some heat is present? Or maybe just some loose heat shield. Do the Cats fail this soon, 12,000 miles?

Any ideas?

thanks, Mike

 

It can be the cats, heat shields, or even the tensioner thingies on which the tensioner bearings/rollers are mounted. The fact that it goes away when warmed up says that either the idle rpm is moving to an rpm where it doesn't resonate with whatever is rattling, or that it's the tensioner (they apparently work better when warmed up). These are bits of information I've picked up second or third-hand from reading various posts here. I'm sure someone will come along and clarify.

Let us know if you figure it out though!

 

Doubt if it is tensioner related, just had the major done by the Ferrari dealer and these of course were replaced. Again, it is not idle related, once the car is warm the rattle stops.
Last night after driving and parking it for 1.5 hours it did not rattle up on start up due to some latent heat still present I'm guessing.

 

Crap...I had this exact problem and something near the bypass rattle needed tightened but I can't remember what it was!!! My tech did fix it though.

I would check the components near there cuz it annoyed the hell outta me and it was the exact same situation you described.

 

Blampee - can you describe what I'm looking for in this 'bypass' you mention.
what does it look like and where is it located?

thanks a heap

 

I know you said that everything was replaced at the major, but are you absolutely certain that both hydraulic tensioners were replaced (in addition to the tensioner bearings). Does your bill show the fitting of two "hydraulic tighteners", part number 157356. I only say this because the symptoms you describe match exactly those of a sticking tensioner which loosens off when the engine is warm.

 

I'm with you Ron.

 

I'm sorry, but my tech did it and I know so little about cars.

 

this guy... between the end of the spring and the copper nut (to include the "tin can" just to the right).
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Press the clutch petal when starting, do you still have a rattle? If it stops the rattling at the start than you clutch disk needs to be replaced or aligned.

 

thanks for all the help and info guys. Appreciate it. I'll be calling my service dept today and ask them questions about the hydraulic tensioner, etc. What exactly does this hydraulic tensioner do and what does it apply tension to?

thanks, Mike

 

I have 99 (20 K) and all service/major was done at dealer (not that it is better), the rattleing seems to come from behind the passenger/driver compartment closer to the fire wall.

I do not belive it is the clutch as it would be from the back of the car. Also if you depress it and it goes away, then it is your throughout bearing. My understanding is that it is normal (my other BMW car has the same) and no negative impact.

The belt tensioners seem to be the most possible cause ......i have searched on this forum and others and nowhere could I find if that is bad or not. My understanding is even new ones will do this when cold ! (could be wrong though).

Anyone can ellaborate on the effects of this temporary lose belt tensioner, can the belt jump/out of timing during those few minutes ?

process of elimination I guess.

Thanks

 

Anyone know the cost to replace this hydraulic tensioner? I did listen to the car last night and it is coming from under the heat shielding over the exhaust (I'm pretty sure). so this is in the same vicinity as the hydraulic tensioner, right?

Mike

 

I have also seen a number of discussions regarding a metallic noise at start up from cold which disappears after a couple of minutes. I too had this noise which could be attributed to a sticky/ineffective/incorrectly adjusted tensioner.

The sequence of photograph were taken during the work I did during winter 2007'

The first picture is where I found no gap between the tensioner body and the tensioner bearing bracket.

The second picture shows the bearing too loose on the belt requiring the tensioner to work too hard to add pressure on the belt resulting in a large gap.

The third and fourth picture shows the old and new tensioner with the retaining pin installed. In this position the gap is too small, approximately 1.5mm.

The final two pictures show the gap as per the WSM, i.e. 2.5mm.

After reading about this start up noise and a few theories elsewhere, if the tensioner gap is too small, the bearing bracket could chatter on the tensioner causing the metallic noise until sufficient heat was in the tensioner to extend the plunger moving the tensioner bearing bracket away from the tensioner housing.

It would seem if the pin is left in whilst the belt tension is applied to make the initial setting, the gap would be too small running the risk of chatter.

After I refitted the engine, and ever since, there has been no more chatter from cold.
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Found these pictures (with new belts, Hill bearings and Ferrari belt bearing tensioners) which show the system quite well.
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"under the heat shielding over the exhaust" sounds to me like the bypass valve.

 

I'm thinking the by-pass valve is most likely at this point. What is the cost of this or is it integral to the exhaust system? Just talked with my service tech and he said he has never heard of an Hydraulic tensioner causing any rattling noises. He suspects either a simple heat shield rattle or maybe the bi-pass valve.

 

Hi Mike. We are all hoping that your rattle is coming from the very rear of the car - something around the heat shields, by pass valve area 'cause that will be easy to fix. The tensioners are at the front of the engine, just behind the bulkhead separating you from the engine. They can only be accessed when in there doing a major (belt change for example).
What made us suggest the tensioner is that the noise goes away after a few minutes (and that you only get it when the engine is started from cold).
Let's hope that you get it sorted soon - and let us know what it was!
Ron

 

Another thing to try....

Get out and have someone gently rev the motor.

Does the rattle sound like it is moving from the front of the engine to the back?

 

The local Ferrari service manager will be coming to my home next week to deliver some new wheel caps (long story). At that time he will listen to the rattle and make an assessment.
These guys treat me pretty good, making house calls and all )

 

On my 348 I have the same problem, But I know it's just the heat shield. Need to tighten it up. Does it stop rattling when you hold the heat shield? Hopefully that's all it is.

Cheers

 

Had similiar noise on my '90 348....sounded like a metallic rattle for a few minutes until things warmed up...then it disappeared.
Turned out to be the alternator... noisy bearings. Rebuilt the alternator and no more noise.

 

An update, the service manager from the dealer listened to the car last night.
by pushing on the exhaust tips he was able to alter the rattling noise so he suspects the air deflection panels on the bottom of the car are touching the exhaust and thinks an additional 1 or 2 washers may provide enough clearance to the exhaust or what ever is touching the panel. Seems a little odd to me, but he is a very experienced guy and will investigate further as the car is going in for new tires soon anyway. The good news is, as this is only 8 months since the major any adjusting that needs to be done will be free- always a good thing )

 

Good news Mike. So something in or near the exhaust system touches when cold and moves out of the way when the heat comes along. Glad that it's an easy fix (and will be at zero cost!). Thanks for updating us.

 

Taking the car in this Friday for new tires and they will address the rattle at that time.
Will report on their findings then.