Technical Engine bay rattle/ticking

[misterbianco]

Apologies if this has been covered before (I did a search which showed a couple of similar things but nothing definitive that I could find); our 500 has developed a rattle form the engine bay.

It's a 1.2 so, while the sound's a little like a hydraulic tappet on start-up, that's not the cause. I think the rattle is coming from either the alternator/air-con compressor area or the induction pipery - either way, from the rear of the engine bay to the left(ish) of the air filter housing as you look from the front of the car.

 

[VilleV]

And this happens now when it´s cold outside and aprox. at 1400-2000rpm? If so mine does it too, a rattle or tappety sound from top of the engine behind the airfilter box. Can only be heard at certain rpm when the engine is warm but outside air cold. This has been discussed widely at the Cinquecentisti forum but no-one seems to know the cause! Someone has proposed it could be the injectors or the throttle body(?), but so far no real solution. What ever it might be it doesnt seem to be dangerous and disappears immediately once the weather warms up. And it seems that it´s only the 1.2 engine that makes the noise.

 

[RobinPJ]

This is almost certainly wrong but a Merc I had used to make a noise that sounds like this - turned out it was a "regeneration valve". For all I know the 1.2 does not even have such a thing but you never know.

PS Can you tell I'm not a mechanic?

 

[misterbianco]

Thanks VilleV, the cold weather/warm engine combination is familiar - it doesn't happen when the engine's cold. I can hear it when the engine's idling though. It doesn't sound too serious, more mildly irritating than anything else. Maybe I'll just have to wait for the weather to improve.

 

[Super Uwe]

I agree - nothing too much to worry about.

Our car has made this noise during the last two winters; it is most noticeable between 1500 and 2000 rpm (as Ville suggests) and will disappear once (a) the weather warms up or (b) when the engine is warm in coldish weather. The only time it doesn't go away completely even if the engine is warm is if the air temperature is very cold.

Our car has been in twice and nothing has been highlighted either time, so that’s good enough for me - I am happy enough it is a random quirk!

However if you are still concerned there are other slightly related threads such as this one where there is a “whistling” sound as well:

https://www.fiatforum.com/500/251205-our-500-sport-59-has-had-new-cam-belt-assembly-anyone-else.html

On the other hand....ignorance is bliss!

 

[VilleV]

The only time it doesn't go away completely even if the engine is warm is if the air temperature is very cold.



Our car has been in twice and nothing has been highlighted either time, so that’s good enough for me - I am happy enough it is a random quirk!

This is exactly how mine does it. The rattle is there while the engine is warming up when it´s coldish, but the sound remains all the time if it´s really cold. My car was in the garage about this last winter but nothing was found. They did propose it´s the EGR valve that makes it, but I reminded them that the 1.2 500 doesnt have one... That´s the level of their knowledge, being a Fiat garage..