Diesel Engine Wear vs Petrol Engine Wear

[Clinterous]

A colleague said to me that with a diesel car, halving the mileage done would equate to similar wear levels of a petrol cars engine! (ie a diesel engine lasts twice as long)

I've heard this some while ago, and wondered if its myth or factually correct?

If roughly correct, given the modern higher powered diesel engines of today, would this still be a good rule of thumb?

[gazza57]

A colleague said to me that with a diesel car, halving the mileage done would equate to similar wear levels of a petrol cars engine! (ie a diesel engine lasts twice as long)

I've heard this some while ago, and wondered if its myth or factually correct?

If roughly correct, given the modern higher powered diesel engines of today, would this still be a good rule of thumb?

Clinterous,
It's difficult to put a factor on it so simply, a diesel usually lasts longer because it's fuel ie diesel is a lubricant, secondly the piston ring material is much harder than it's petrol counterpart because of the much higher compression ratio usually 23:1 or higher.
A lot of other factors come into play, for example the oil in a diesel contains lots more particulates soot, carbon etc and is always almost black even just after a change and will require more frequent oil/filter changes. I think it would be safer to perhaps reduce the mlieage by 30% rather than 50%.
Gazza57

[adamss24]

Just to add that a diesel engine is way better engineered/ stronger built and it revs less than a petrol engine. I have opened/reconditioned diesel cylinder heads with over 300 K and i could still see the crosshatching on the piston bores. Having less electronical parts, no. spark plugs, HT leads, and no Lambda probes, its also more reliable and cheaper to run as well ...

[Captain Answer]

A well built diesel will always outlast its petrol equivilant where operating conditions are similar

[RickT]

The main factor to think aboput i think is how its is drove... so example an Diesel engine which is red lined its life compared to a Petrol thats had it easy..

I know a few Petrol engines which have had 500k on them still going strong,

Rick

[stonedagain]

It all depends on the engineering & quality of materials used. Years ago, I removed the head from a BMW 525e I had at the time, & the original honing marks were still clearly visible in the bores with no measurable wear evident. This was after 165,000 miles of hard life & assuming it had'nt been clocked. The same applied to a 518i after 145,000 miles.

[pedropete27]

The main factor to think aboput i think is how its is drove... so example an Diesel engine which is red lined its life compared to a Petrol thats had it easy..

I know a few Petrol engines which have had 500k on them still going strong,

Rick

Hey Rick, what a comparison. I suppose if you had a diesel engine which had never been red-lined up against a brand new petrol car which had been purchased and immediately placed into storage then the petrol engine will outlast it....mmmmm, never thought of it that way!!!!!!!!!

The question was asked to compare equally ie mileage, driving style, driving conditions etc your example blows this out of the water

It is common knowledge in the engineering world that on comparison a diesel engine used in the same way will outlast a petrol engine by thousands of miles. Just because you drive a petrol car, you are allowed to bring your head out of the sand. BTW I drive both petrol and diesel, so I speak from experience.

[MalcQV]

Hey Rick, what a comparison. I suppose if you had a diesel engine which had never been red-lined up against a brand new petrol car which had been purchased and immediately placed into storage then the petrol engine will outlast it....mmmmm, never thought of it that way!!!!!!!!!

The question was asked to compare equally ie mileage, driving style, driving conditions etc your example blows this out of the water

It is common knowledge in the engineering world that on comparison a diesel engine used in the same way will outlast a petrol engine by thousands of miles. Just because you drive a petrol car, you are allowed to bring your head out of the sand. BTW I drive both petrol and diesel, so I speak from experience.

Steady on, Rick was only expressing an opinion. This is called a debate.

I know of many petrol engines that have lasted many 1000's of miles. I agree in general a diesel will probably last longer, amongst other things they only rev to about 5k tops so there is going to be less wear. However with engineering tolerances being so good today, if driven with respect the petrol engine has equally good longevity.

Statistics are what we probably use to come to this conclusion, as statistics are used when science gives us the wrong answer .

Only recent has the diesel engine been any good. One of the first ones I remember driving was a 1995 Rover with no turbo and absolutely horrible to drive. Diesel engines are so good now more people are buying them driving them harder. I don't expect the longevity of the diesel to be much different from a petrol engine in future tests.

[pedropete27]

Steady on, Rick was only expressing an opinion. This is called a debate.

I know of many petrol engines that have lasted many 1000's of miles. I agree in general a diesel will probably last longer, amongst other things they only rev to about 5k tops so there is going to be less wear. However with engineering tolerances being so good today, if driven with respect the petrol engine has equally good longevity.

Statistics are what we probably use to come to this conclusion, as statistics are used when science gives us the wrong answer .

Only recent has the diesel engine been any good. One of the first ones I remember driving was a 1995 Rover with no turbo and absolutely horrible to drive. Diesel engines are so good now more people are buying them driving them harder. I don't expect the longevity of the diesel to be much different from a petrol engine in future tests.

MalcQV

yes I agree it's a debate...so why are you pulling me up? I was expressing IN MY OWN OPINION that Rick's point was a stupid comparison....which it clearly is!

[Captain Answer]

Only recent has the diesel engine been any good. One of the first ones I remember driving was a 1995 Rover with no turbo and absolutely horrible to drive. Diesel engines are so good now more people are buying them driving them harder. I don't expect the longevity of the diesel to be much different from a petrol engine in future tests.

Seriously? Your taking the fact you had a 95 diesel rover that was loosely bolted together in longbridge to draw the conclusion that diesels use to be rubbish?

Diesel engines have been chosen for many applications for well over fifty years because of the power, reliability and performance that they offer over petrol engines often times where they could not even operate.