Being stuck in traffic is something we all hate, whether it be making us late or just the shear frustration of not being able to move that last 100ft to the next junction and get out of the jam.
Many of you know being stuck in traffic is not good for your fuel consumption, when you are usually in a lower gear leading to less bang for your buck in fuel economy both from the lower gear, and once some speed is gained it is all lost as heat when you brake meaning a waste of energy and higher fuel consumption.
It is not surprising then vehicles in stop start congestion type traffic classically have much higher fuel dilution levels than cars operating at faster, but more sensible constant speeds on the open road. Steady speed at peak operating conditions is the most economical as once the initial inertia is overcome it takes very little fuel to keep it going, but accelerating uses more fuel. Hence why acceleration as in stop start traffic leads to more fuel delivery and unless the acceleration continues at the same rate not all the fuel is burnt leading to fuel dilution. Even standing still, aka idling the engine in traffic can lead to ~25ml of fuel consumption every minute (average car can vary from 5ml to 40ml depending on model). Much of this fuel in an idling situation is not fully burnt (as the engine is not at peak operating temperature), washes lubricant from the cylinder walls and enters the sump.
High fuel dilution can lead to fire risks, and the thinner lubricant film can lead to serious engine wear. Both of these reasons are why you should be monitoring your oil regularly to check for these situations.
For those of you with the cars that stops when you put the handbrake on and the car in neutral, you may be thinking you don’t need to sample as fuel consumption is lower. However, stop-start technology changes the average vehicle life time stop-starts from ~50,000 to 500,000, I.e. a 10 fold increase. Although they do save on fuel consumption from idling, this puts a lot of wear and tear on the engine. When the engine stops the weight of all the engine components means the lubricant film is squeezed out and the only thing saving the engine from metal to metal wear is the boundary lubrication layer formed from the anti-wear additives. Hence with a 10x increased demand on the lubricant anti-wear additives by using this technology you need to make sure your oil is in peak performance to ensure the crankshaft is not about to fail.
Hence oil analysis is a great way to confirm your oil is not becoming full of fuel or the anti-wear additives are not being spent too early by those traffic jams you put your car through each day.
If you are regularly stuck in traffic, rather than getting frustrated and try thinking of what your oil is having to go through, and then consider sampling it to check its still fit for use.