355 Rattling noise on cold starts

Hey guys,

I have a rattling noise on cold starts and as soon it start to get warm up or rev up a bit , it goes away. We can hear it clearly from the timing belts zone.

Recently we did a major service in the car including pulley's/belts change among a large list of things, though the car only has arround 3.5k miles from new, in such large list of servie/repair we also changed the A/C compressor bearing and full new TUBI header/exhaust system to avoid the known crack header issue of Ferrari while we were there.

There's another F355 at the shop we have done a lot of things as well (F355 life I guess....) and it sounds the same on cold starts, although thi scar has stock exhaust system and more than twice the millage. Though, we have not done the major service or pulleys/belts change but we are on it soon to do.

I know this rattling noise are somewhat common and can be a couple of things to look at, but I guess with all done to this particular car, I think the culprit is the hidraulic tensioner of the cam belts which were not changed because we were not award that this was in bad shape (well, until right now we suspect it's the problem of the noise) and looking at the graph not sure if only order two new #22 item only or as well the #33 item which require TWO of them as well.

The #22 part is arround $314 each and #33 is $225 each.

Is common to replace the #33 when changing the #22 part?

Thanks


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Part 22 should be putting constant pressure on the bearing assembly. Part 33 should be compressed at all times and I don't see how it would rattle nor really how to replace it.

Do you have any loose belts post service?

 

Failed hydraulic tensioner would be my bet. My car was recently doing the same and would stop once warm. I’m about to drop the motor and will see if I’m right.

 

Just updating this thread, my rattle on cold start was as expected a failed (collapsed) hydraulic tensioner. The other side is fine and functioning.
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Never understood why they are called hydraulic, aren't those a bucket with a spring? Hope those are available new the 348 is NLA, good catch!

 

The F355 timing bearings are held under tension via spring tensioner with hydraulic dampening. It’s basically oil filled with a small orifice to provide dampening like a shock.

And yes they are available new, I already have them both to fit.

 

Awesome good to hear good to know the symptoms thanks.

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I can see that yours apparently collapsed. Collapsed would imply the spring failed. Why would the noise go away when warmed up? Doesn't seem to follow.

 

Thermal expansion of the hydraulic fluid.

 

Quite often there are signs of oil leaking from this type of tensioner. From around the pushrod. That is the most common indication for me. Ive changed dozens of Subaru items for that reason. Leaking can happen over a long period of time and is not so obvious then. We used to look for slack movement of the pushrod by pressing it in against something when removed. Quite often you could use your fingers if it was that bad. Anything up to 5mm before the damping effect. Always worth checking even if not noisy.

 

Is there a check valve behind the small orifice through which the engine oil is supplied under pressure?

 

The tensioners are independent of engine oil. They are a sealed system and generally are replaced rather than repaired.

 

Interesting, must be sealed on the 355 as the 355 parts diagram does not show it getting oil and it definitely stated Hydraulic. Like a sealed lifter perhaps where the 348 is basically a spring according to the parts diagrams. No hydraulic on the 348 #30 but it is hydraulic on 355 #22.


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Here is the idea.....

HydTens.html

 

That’s a very helpful article.

 

Also if your belts stretch a little can cause then to rattle a scooch when cold

 

Tim's comment is the only one that makes sense to me as for going away when warm. But it also probably indicated that the belts weren't tensioned correctly to start with.

 

Oh, and until it is verified that the noise is coming from the timing belt mechanicals all of the is just meaningless speculation. IF the noise is from the belts the only way to find out what it is is by dropping the motor.

 

Wait, I thought he did drop it and found a actual collapsed tensioner?

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That was Elliot's post. The OP hasn't posted since #1. Probable trolling.

 

Haha that makes sense I thought that was mighty fast

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I have two F355 with the same symptom, one we changed new belts and pulleys like stated and the other has not been serviced for long time such parts, so, when I replace the belts and the pulleys, I will change (order) the two hydraulics tensioners and we will see how it goes (and report back). In the F355 that we changed the belts, we adjusted it as per manual indicates and triple checked that before assambling all back so we know the belts are up to manual specs adjusted, it just rattles in cold and below 1k rpm i.e. when you release the clutch with no throttle input.

 

Hi Ricambio. How are you? I have a 355 with the same symptoms. Was really the tensioner? And how risky it is to drive the car with this problem?
PS: my car had the drop engine service 1 year ago, but it seems they replaced only the belts and the bearings according to the service invoice.
Thanks in advance. Regards!

 

Nice catch Elliot
What did the motor sound like exactly
Kind of like tappet noise from the cams maybe. Or some of my gas engines sound like this when the variable cam timing is worn and oil pressure is low at idle
Kind of sounds a bit like a diesal. just wondering for future reference

 

Hi,

Due the covid-quarantine , all got paused and took more time than the scheduled. The car is at the shop still, engine is back in place with all new exhaust system and is ready to add all the fluids/bleed, etc, except the coolant which I ran out of it and next week should arrive the missing part to fill up the system and finally start it and see how ti goes and if th erattle goes away this time.

I'm not sure if this rattle noise (if is from the hydraulic tensioners) are a huge risk or not in th elong term, but in the short-mid term I would say not. This is because the other two F355s has the same rattling noise at cold sstarts and been like that for the past years and no issues at all, though, are cars that doesn't see much use.

I will report back when I test drive this car and has several cold starts to see if the rattling noise is gone or is still there.