Exhaust Problem?????

[guest593]

Exhaust
Am I going daft?
Since we’ve had this cold spell of weather here in Scotland I think I’ve noticed a difference in my exhaust when starting the car on really cold mornings. To me it sounds like the exhaust is blowing slightly but once the car warms up it stops and the car reverts to its normal almost silent running.
Has anyone else noticed this?

[JazzyB]

No problems down 'ere in the south but I'm sure a garage check would put your mind at rest

[guest229]

I have noticed that when the air temp. is around the -10C that the engine noise on start up is much higher , when it warms up the noise disappears. I have put this down to piston slap which other respondents have also noticed provided that the noise disappears during warm up I wouldn't worry unduly.
          For info: my car is 2007CVT with 6800mls on the clock and has been fully dealer serviced.
         

[culzean]

The engine responds to cold starting by increasing the fuel / air mix (used to be called richening the mixture) and also changing the point where the spark plugs fire, this could cause a change in the exhaust note.  You may also get mechanical noises caused by piston slap and maybe a bit more tappet noise when the engine is very cold, as the metals warm up and expand these will go disappear.

As long as the noises go away as the engine warms up I don't think its worth worrying about them.

Just feel happy that your well-made car starts reliably at -10C.     

[JazzyB]

I have noticed that when the air temp. is around the -10C that the engine noise on start up is much higher , when it warms up the noise disappears. I have put this down to piston slap which other respondents have also noticed provided that the noise disappears during warm up I wouldn't worry unduly.
          For info: my car is 2007CVT with 6800mls on the clock and has been fully dealer serviced.
         

That's a very low mileage 'ivorbeck'?

[guest593]

The engine responds to cold starting by increasing the fuel / air mix (used to be called richening the mixture) and also changing the point where the spark plugs fire, this could cause a change in the exhaust note.  You may also get mechanical noises caused by piston slap and maybe a bit more tappet noise when the engine is very cold, as the metals warm up and expand these will go disappear.

As long as the noises go away as the engine warms up I don't think its worth worrying about them.

Just feel happy that your well-made car starts reliably at -10C.     

I don't think it's piston slap I think you're correct about the noise coming from engine because it happens only on cold starts. -7 this morning!!!

[guest229]

Ref. my car mileage------ due to being a "wrinkly" I tend to use my "blue card" whenever possible. Hopefully this is doing my bit for the environment and it is certainly cheaper.
       

[guest229]

I was unaware that the spark was retarded as well as richening the mixture on cold starting and this will affect the exhaust note noticeably, I say this from my heady days of youth when I rode Triumph Tiger 100 with manual spark advance/retard and you could almost play a tune with the exhaust note by moving the handlebar mounted lever.    Happy days!

[Geoffers]

I say this from my heady days of youth when I rode Triumph Tiger 100 with manual spark advance/retard and you could almost play a tune with the exhaust note by moving the handlebar mounted lever.    Happy days!

Beeza Shooting Star man here! Auto advance/retard.
My 350 Goldie had manual advance/retard though!

[guest229]

Nice bike! Two of us went everywhere togther my pal rode a Shooting Star I always admired it.

[Geoffers]

Ahhhh! Happy days! 

[guest1132]

I also get the mentioned exhaust noise when it is cold. It's as if the exhaust is blowing slightly?

It is a thrum sort of sound that comes at about 2500-3000 rpm.

After about 10 mins it vanishes though- the car still runs just as smooth however!

[DV]

I`d like to mention the engine oil can help a lot in cold weather too.
I`m using Castrol Edge 0W-30 oil.
I think my engine is not as quiet as it was with ,eg. 10W-40 oil, but in cold weather helps a lot to the engine, (eg. reduce engine wearing, helps with the fuel consumption,emission etc.) because this oil is thinner than the 10W one. W stands for winter.
The other thing the engine oil has to warm up too and when it is warmer running smoother than it was cold.
At the start of the engine the oil is in the bottom of the engine and the oil pump has to pump it up and as long as the oil is not everywhere, the engine is louder, even in cold weather (this oil pump thing last for a few seconds only).

[guest882]

don't worry about the sound the engine makes when started up at -10 C.this winter we had -26 C and it sounded like a diesel for a minute or so..

[guest229]

Hells bells!!! Where do you live -- on the back side of the moon?