And the little niggles keep cropping up with my new Six.

I’ve now noticed that I have white smoke from the exhaust - pretty much constantly but with no other symptoms of HGF. Mysteriously, the issue presents itself from just one of the tips which makes little sense to me given that the exhaust is not separate for the full length.

Any ideas?

 

My first suspicion would be it's steam rather than smoke and as a result of condensation build up in the exhaust.

This especially happens if the car is used for lots of short journeys or if you have done a lot of cold starts in the garage/driveway without running the car for very far. This is true of any car but the X300 exhaust seems to be particularly prone to it (mine was anyway as I did very low mileage in it).

Take the car for a good long run so that the full exhaust gets hot and see if it burns off. On a few occasions I split my exhaust at the rear silencer and drained it!

 

The car is used very regularly - I commute 15 miles each way every day and it’s still producing the white smoke at the end of a journey. It may well be steam for some reason but not through lack of use…

 

The white smoke can also be coolant or oil leak into cylinders

The end of journey may be related to engine block gets up to and still hot , which is where worppage / and effects of happens

You can carefully and accurately check both fluids level for change , so that's free

watch that it doesn't overheat , too bad the X300 does not have a red overheat light as someone had to point that out to me

So how do you tell ......................someone may be able to tell the coolant temp gauge mark on a full warm engine

The thermostat is set to keep it below X degrees . 186 F off the top of head if someone may help me out

So with a good thermostat the engine coolant temp sensor should no get above that temp as read on a ELM - 327 device

The instrument gauge is a poor dummy gauge as not so accurate or timely . it is the single wire temp " bulb " atop the thermostat

The 2 wire temp " sensor " next to it only feeds the engine ECU for open / close loop command and that temp is what you would be reading as the ELM - 327 device

To know both fans are kicking on in the driveway there is an easy paperclip test if you need it as it is imposable to get the high fans in the driveway without the test , besides , there is a TSB to not run up the engine too high revs in driveway , probably related to transmission cooling as the X300 does not have a transmission cooler

 

A garage can perform a cheap coolant leak test with pressure gauges , but this does not cover oil

My brother had a warped head and coolant leaked into oil system will foam the oil so will climb the oil dip stick , eventually the compromised oil seized the engine bearings up , so the engine was toast

Oddly foaming the oil is how to get the airliners auxiliary engine started at altitude ( - 70 below zero ), needed to get electrical power as a alternate cockpit instruments source ( some crashes )

This foaming of the oil vastly reduces viscosity friction in the bearings to get APU past a certain percentage ( 20 % ) with it getting past that point to carry on forward to 100 % RPMs at all times once fuel is added at 20 %

Once the APU is started the foaming of the oil will be stopped ,

 

Any chance this could be the result of a leaking injector?

Because it's only happening on one bank, I'm assuming it is something that is affecting only a specific cylinder or two.

I hope it is not head gasket related.

 

Vee , not to be questioning your great knowledge, but a rich fuel mixture / stuck injector would be black smoke as I experienced on mine including exhaust spitting on closed garage door

You helped me resolve may rich issue of 25.4 % ( ELM - 327 results limit on STFT ) , vacuum leak caused , missing vacuum line

 

You’re right, it would.

Have you checked for oil in the spark plug wells? Might want to check the plugs as well, while you’re in there. You could find some kind of evidence.