This is an odd one to diagnose, but your input is appreciated

It's my Stilo Abarth this time. Often when I start the engine and back out of my garage/five point turn in the driveway, etc. the engine has a growling sound to it. Really, not especially loud but a Grrrrrrrrrrrrr sound that rises and falls with revs. It's not noticeable when driving, being only noticed at just around idle speed.

What makes this harder to diagnose is that it doesn't do it every time, and tends to be most apparent when the engine is cold.

Late last year I replaced the cambelt, tensioner, water pump, and idler. Maybe I should recheck the timing belt tension?

Any other likely causes?

-Alex

How did you get on? To isolate a noise use some tubing to listen to localised areas. A stethoscope is handy too. Use it a lot at work to trace faulty components.

Maigretnz said:

How did you get on? To isolate a noise use some tubing to listen to localised areas. A stethoscope is handy too. Use it a lot at work to trace faulty components.

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Thanks, I've just ignored it and haven't noticed it for some time now. I reckon it's probably the cambelt cover warped and rubbed on the bottom pulley. I lost the pointer off there (hard to remove the cover without breaking that pointer off, and it had been glued on before). I glued it on again and it fell off again. Life goes on, y'know!

I do have one of those stethoscope things but the sound has been too intermittent to use it. It's been at least 3000km without the sound.

-Alex

Is the power steering electric or hydraulic? Hydraulic steering will often make more noise when cold and asked to work hard, like manoeuvring out of the garage.

portland_bill said:

Is the power steering electric or hydraulic? Hydraulic steering will often make more noise when cold and asked to work hard, like manoeuvring out of the garage.

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Electric. It could be alternator bearings or aux belt tensioner, related to the additional electrical load created by the steering. You are right in that getting out of my garage involves a five-point turn!

Since the Stilo has been in regular use (the Spider being off the road for winter), maybe the battery is being kept more topped-up. I do feel a bit sorry for it as on some short trips it doesn't quite warm up (outside temps now being 5-10 degrees). Might treat it to an oil change. Thanks for the input.

-Alex

FWIW Alex, yours is not the only Abarth that does this. My wife's car has done it on and off for several years now and I'm in no doubt from your description it's the same noise. Sometimes it can be quite loud, but if it's doing it when I stop, by the time I'm out and lifting the bonnet it has faded away! I'd describe it as almost a gargley growl, like a teddy bear. Certainly related to engine rpm, but not the timing belt I think, as that was changed earlier this year and no difference. It can disappear for many weeks at a time, I suspect it can be persuaded to do it by giving it some beans, but it's not proven.

No help I know, but if I discover any more info I will post here.

Yes, Ralph2! That sounds like exactly the same symptoms. Open the bonnet and the noise has stopped.

I'll be listening out for the gargly teddy bear...

-Alex

alexGS said:

Since the Stilo has been in regular use (the Spider being off the road for winter), maybe the battery is being kept more topped-up. I do feel a bit sorry for it as on some short trips it doesn't quite warm up (outside temps now being 5-10 degrees). Might treat it to an oil change. Thanks for the input.

-Alex

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Sorry for going off topic Alex but I still can't get my head around the fact that you guys have your winter now! Lol ......... We're currently undergoing a heat wave over here in "blighty" and are seeing temperatures up to 32 degrees! With tropical style thunderstorms weather is a funny thing!

Just remembered this thread from last year...nothing more to add to it yet...except the hot engine cover was to do with a distorted heat shield on the exhaust manifold.
https://www.fiatforum.com/stilo/310980-abarth-engine-noise-not-normal.html

Thanks gadge - the last few days feel like spring in comparison to what we've had - it's now sunny with some warmth in the sun, 15 degrees.

Thanks Ralph2 for the link to your thread - seems we have a similar sound we're chasing.

Small update: as of this morning, I noticed the growl sound for the first time in a while. Then I realised that the air conditioning was on (after I'd pressed the rapid-demist button last night). This may have been a coincidence, but I think the air conditioning compressor might well be the cause of the growl. I only use the air conditioning some of the time (winter or summer). I'll get the pressure checked in the next few months before summer.

-Alex

Make sure the oil is replenished not just the aircon gas. There is only a small amount of oil in the gas, which has to lubricate the pump and prevent the seals from drying out. Hopefully growl is low gas, not impending doom.

Thanks PortlandBill,

I was thinking about that too - having a bit of extra oil put in - but there are risks with that as well: 1) oil must be compatible (ester oil or PAG, probably PAG), and 2) too much oil reduces efficiency.

I'll probably get the system drained down and completely recharged with fresh refrigerant/oil. In the meantime, I won't be using it just to be on the safe side.

-Alex

alexGS said:

Small update: as of this morning, I noticed the growl sound for the first time in a while. Then I realised that the air conditioning was on -Alex

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Right on the money Alex. I have just proved beyond any doubt the aircon is the culprit. I'll be interested to hear of any improvement if you do add some oil.

I had the air conditioning serviced and it made no difference. Lately I've been driving another Stilo Abarth and its air conditioning also growls! Therefore, I think we can put this one to bed like Mythbusters do: "Confirmed".

-Alex

i dont believe you... show me the Kari and ill believe you!

Ha yep we're done.

I also get this noise every time I start up. One day the whole car was groaning and whining so loud I could hear it with my windows up and noise reflected louder off passing cars, then there was a clunk and a hiss and everything back to normal. Aircon still working fine and no leaks. Think its just the pump and valves etc getting sticky with old age...