Ideal exhaust pipe colour

[jenevers]

I read somewhere that the inside of the mouth of an exhaust pipe should be light brown if the fuel is being burned correctly.

Is yours sooty, oily or light brown?

[GRLMK38]

I have only ever heard reference to this in relation to petrol engines.  My diesel engine produces dry soot and I have been told by people who know better than me to only worry if it becomes oily.

[WotEver]

Certainly my diesel car has a black sooty exhaust. 

[cuthound]

1 hour ago, WotEver said:

Certainly my diesel car has a black sooty exhaust. 

That's what I would expect from the exhaust of any diesel, unless it is fitted with a DPF, in which case the exhaust should be completely clean.

[WotEver]

2 minutes ago, cuthound said:

That's what I would expect from the exhaust of any diesel, unless it is fitted with a DPF, in which case the exhaust should be completely clean.

Mine has a DPF (and it works) but the exhaust is still black and sooty. Okay, it’s not VERY sooty but it’s sooty nonetheless. 

[Ray T]

I've got a nice cream exhaust pipe. 

Please note the tatty drooping fenders have been replaced.

Edited January 4, 2018 by Ray T

[cuthound]

2 minutes ago, WotEver said:

Mine has a DPF (and it works) but the exhaust is still black and sooty. Okay, it’s not VERY sooty but it’s sooty nonetheless. 

My finger comes out clean when I wipe the inside of the exhaust with it,  unless i have done a very short journey.

[WotEver]

1 hour ago, cuthound said:

My finger comes out clean when I wipe the inside of the exhaust with it,  unless i have done a very short journey.

Oddly, that’s not something that I’ve ever felt the urge to try...

[jenevers]

4 hours ago, GRLMK38 said:

I have only ever heard reference to this in relation to petrol engines.  My diesel engine produces dry soot and I have been told by people who know better than me to only worry if it becomes oily.

Thanks for that info. I didn’t realise.

must admit I’ve always been puzzled as my exhaust is dry and sooty but doesn’t smoke at all.