My engine is generally pretty quiet. But there is a light but audible tapping noise that follows the engine note. It seems to come and go - not sure if temperature related. If it was a petrol I'd say it was knackered, but I don't know what sort of noise you expect from a diesel. I know in the old days they sounded like an old van.

Is this normal or do I need a new engine? It's still under warranty so no worries either way.

Without hearing it is difficult to say/diagnose. There are plenty of engine items that will 'tap'. Valves, injectors, combustion noise (typical diesel knock) and EGR valve which is modualted with a square wave, i.e. opens and closes on a ECU determined period/rythm.

Agree with Nick - hard to say without hearing - but;

My 2.4 sounds like cavaliers used to when the cams had been squared off, it's engine/atmospheric temperature related and sounds worst when the DPF is regenerating. The noise hasn't altered in the past 26,000 miles so I've put it down to a "characteristic". Given how much sound insulation Fiat put round the engine (i.e. next to none) I'm surprised the car sounds as quiet as it does! I'm always twitchy about engine noises after owning a car with a VW VR6 engine..

As always, might be worth keeping an eye on in case it is a problem and gets worse before the warranty expires. The JTDs don't seem prone to top end problems but I suppose there's always an exception.

HTH.

My 3 year old son describes the tapping sound my 1.9 mjet makes as like a train whjen i start the engine. I took mine to 2 Fiat specialists who both said the same thing that it's just the car and nothing to worry about. My dads Alfa 156 does the same and so does some of the alfa 159 diesels.
But as above it's hard to say what the problem is without hearing it.

Thanks for all the info. It's currently waiting for a new EGR valve, so I'll see what happens after that's done. I'll mention it to the Fiat garage when that's done and see what they say.

The general engine note is pretty quiet, but this tapping is noticeably louder. Not "loud" but definitely audible. I think it's only when under load. But I love the turbocharger whistle - that's a big bonus of this engine. I hope this is a normal noise, as it sounds great - the other I test drove also made the same whistling noise, but don't remember if it also tapped.

DoIDon'tI said:

it's engine/atmospheric temperature related and sounds worst when the DPF is regenerating.HTH.

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How do you tell when it's doing this? How often typically?

Bunny's croma makes a "psssshh ta pssssch ta" noise while cold, almost as if there is a compressor attached to the crank.

Local fiat/alfa garage have said they hear it a lot from Alfa 1.9s and after replacing all belts and pulleys it still makes that noise!

Hellcat said:

Bunny's croma makes a "psssshh ta pssssch ta" noise while cold, almost as if there is a compressor attached to the crank.

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Hehe. I'll join in the onomatopoeia. Mine's a d-d-d-d-d-d-d noise that varies in rate according to the engine revs.

Maybe we can re-create the 'Honda' advert using only Croma engine noises?

I'll play! 2.4 sounds like this;

Low speed, low engine revs - warblewarblewarble overlaid with taptaptaptaptap

Cruising - rumblerumblerooooooar (road surface noise only)

Hooning - Woooooooooaaaaaaaaaaaaaarrrrrrrr overlaid with taptaptaptaptap

DPF regen at low speed - rumblerumblerumble (deep exhaust note) overlaid with TapTapTapTapTap

HTH

Doofer said:

How do you tell when it's doing this? How often typically?

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Throttle response goes a bit 'light' (hard to describe), idles slightly faster, deep exhaust note, fuel consumption about 15-20MPG, 'fried clutch' type smell when you get out of the car just after it's finished. Oh, and a slightly increased tapping noise from the engine.

Nothing whatsoever to worry about, you'll get to know what I mean once you've had the car for a while. On average my car regens between every 500 and 1000 miles depending on driving conditions and style.

HTH.

Any suggestions as to the cause of mystery noise affecting my wife's 1.9D 16 v automatic? Occasionally, as she accelerates or sometimes decelerates, you hear for one or two seconds a noise which is difficult to describe, but imagine if you will two plastic discs, one stationary the other rotating. They should not touch, but for some reason contact is made for one or two seconds making a whirring noise. This in no way affects the performance of the vehicle which is 3 y.o. on an 06 plate and has less than 12000 on the clock. The local dealer where the vehicle was purchased and has been regularly serviced, at first denied hearing the noise on a road test. When I insisted on going out with a senior technician at the wheel, we both heard it and he said that it was almost certainly a turbo fault. The subsequent visit by a Fiat engineer to check his findings resulted in a denial of faulty parts but was described as "an induction noise", whatever that is. Appealing to Fiat via email has resulted in a polite brush off. I am left with a Croma that performs perfectly but that I assume any future prospective purchaser would turn down flat on hearing the intermittent noise, or that the dealer would offer bottom dollar for on a p/ex deal, knowing of it's history. Suggestions?

When the EGR valve was playing up / clogged on my car, there was a very noticeable wastegate noise when changing from first to second and second to third (my car is also auto). Since changing the EGR valve the noise has reduced to acceptable levels i.e. almost disappeared - I'm very fussy about noises coming from my car after timing chain issues with my last car.

If the car is performing OK then I'd personally check all the air hoses / connections, then clean the EGR valve, then get an independent specialist to have a look. If they connect a diagnostic computer to the ECU they will be able to monitor turbo pressure and go from there.

The turbos used on these engines have a good reputation, it's much more likely to be something simpler / cheaper.

Hope this helps, and you get it sorted.

DoIDon'tI said:

If the car is performing OK then I'd personally check all the air hoses / connections, then clean the EGR valve, then get an independent specialist to have a look. If they connect a diagnostic computer to the ECU they will be able to monitor turbo pressure and go from there.

The turbos used on these engines have a good reputation, it's much more likely to be something simpler / cheaper.

Hope this helps, and you get it sorted.

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Many thanks for your suggestion friend. A new EGR valve was fitted under warranty some six - seven weeks back after the car died and was towed by the AA to Ancaster Fiat at Catford. The mystery noise started long before that incident and continues now. Ten days ago I paid around £85 for Ancaster to "strip" the turbo, (their terminology), and check all air hoses and connections, they say that they found no fault. I do however know an Italian guy who owns a garage that specialises in Alfa, Lancia, Fiat and all things Italian, I'll ask his advice. I hadn't considered him prior to this as the warranty required that only approved Fiat dealers were used.

Frank 47074 said:

Any suggestions as to the cause of mystery noise affecting my wife's 1.9D 16 v automatic? Occasionally, as she accelerates or sometimes decelerates, you hear for one or two seconds a noise which is difficult to describe, but imagine if you will two plastic discs, one stationary the other rotating.

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My 2.4 auto makes a sort of whirring noise when "thinking" about changing gear. In sequential mode its telling me to change down. I assumed it was just expressing pain.