Technical Cold Start Strange Engine Sound - 1.8 Stilo

[vladof]

Hi guys,

I seem to have an issue (I think) with the engine in my Stilo.

When starting cold, it makes a strange noise. I cannot describe it, but I've made a video of it below. This started ever since I came back from a major road trip, and I was in a hurry to get to the airport fast so I drove 100 mph for a long time (which shouldn't be an issue anyway), then left the car standing, not started, for about 3 weeks.

The noise is only visible for 1-2 minutes during cold start. After the choke is deactivated, sound is gone. Revving the car to the same RPM as choke did does not replicate the noise.

The car had it's oil changed 9000 km ago. The oil was a little low, but not beyond the dot. Oil used is Petronas Selenia 10W40. Been using this oil ever since I've bought the car, it's also recommended by FIAT. Filters changed 10 months ago as well.

The camblet, etc, have been changed in 2008 at 88000 km. The car now has 142000 km, so everything is due this year.

I've opened the oil cap and listened to the engine running, it doesn't seem to be affected by the rattle in any way and, apart from the diesel sound coming from the variator, sounds just fine.

Could you fine people please advise what you think this is? Noise starts at 00:00 and ends on 00:55.

Thank you so much.

Vlad.

http://youtu.be/j9Vc5F46o-Q

 

[katanabandit1]

sounded just like mine when the manifold at the front had little pin holes in it. The pin holes close as the engine gets warm and the metal in the flange expands. I had ine welded by a friend about 6 years ago. Never had a problem since.

Worth a check anyway but to do it it means having the aircon pipes removed to get at it and remove then obiously regased. Well worth it though.

 

[Yellow Peril]

Bear in mind could also be the variator on the way out. The 1.8 engine has one of these...though yours probably does not sound enough like a diesel to be a failing variator...

 

[vladof]

Thank you for your replies.

I'm not sure it's the variator, it seems like something's loose somewhere near the engine.

To be honest, it could also be something banging on the engine because the rhythm of the noise is not synched to the function of the engine but more likely to vibrations it makes. The engine vibrates more when cold, so it could be. The sound is irregular and it also does not do it instantly after turning on the engine. The engine delivers power at top health. I do not feel anything wrong in how the car behaves on the road.

It could also be exhaust related maybe?

I'm just trying to get an idea if you guys have ever experienced something like it so I know where to check. If not, I will proceed with exhaust and loose parts that may bang on the engine.

Thank you.

 

[vladof]

Just an update on this, the noise hasn't got worse but I can now reproduce it if I accelerate in neutral and let the revs fall.

It seems to be coming from under the exhaust heat shield. The shield has not been removed since 2002 and the bolts are coroded in.

Any ideas of what could rattle in there and if it's serious enough to need immediate attention?

Thank you.

Vlad.

 

[vladof]

Hi,

Was wondering if anyone can help with this.

The noise has developed into something louder and worse now.

Here's a video to the sound. https://goo.gl/photos/ymypoNLv2fjgnkhB8

I have replaced the variator in January 2015, had a timebelt change including water pump. I have replaced the whole exhaust including all the rubber mounts and flexible pipe.

The sound is louder on the auxiliary belt side, but I cannot pinpoint an exact location.

Scared to drive the car, some say it's the engine on it's way out. Still looking for proper advice.

Apart from the sound, the car drives great. Engine runs smoothly and delivers the same amount of power as before.

Any feedback would be much appreciated.

Thank you.

 

[mjenoe]

Probably the variable intake causes this noise. If it is stucked in any position and cannot initialize himself . Nothing serious.

 

[Ralf S.]

I don't have sound at the moment but a clanking or knocking at random, not connected to the engine speed, is probably not the engine but something around it.

I would first remove the auxillary belt and see if the sound disappears. The alternator light will come on but that doesn't matter for a few minutes.

If the noise disappears then the problem is probably the alternator or the crank pulley.

The alternator pulley bearing can fail and allow the pulley to move in and out on the spindle, or wobble. It may be striking something.

The crank pulley has a rubber centre and that can perish which makes the pulley flex, so that the pulley or the screws tap the engine casing.

It could be an air-conditioner pulley (a lot of pulleys in there.. ) but those seem to not go wrong so much.

If removing the aux' belt doesn't solve the noise then it would have to be something else. If the sound is louder down by the bottom corner of the cam-belt end then it could potentially be the water pump, just because of the location. How old is it?

Remove the cam-belt cover and have a look what's going on. If the water pump bearing has collapsed the pump pulley will be moving about and whacking the cover. Eventually the belt will fray against the cover, then either snap or jam.

In either case your engine will be wrecked, so when you have removed the aux belt, remove the cam-belt cover first and have a look to make sure there is no visble damage or wear inside the cover where the water pump or cam-belt have been touching it. If it all looks "okay".. then test for the noise with the aux-belt off (as above).

With the cover off you'll also be abe to see whether the cam-belt runs straight or if it's wobbling (damaged water pump bearings or any other pulleys or tensioner problems).

Ralf S.