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.

[paul20v]

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 ...

less electronics i think not modern diesels are jammed with as much electronics as petrols with single rail injection fly by wire pumps cam sensors crank sensors ,also most now have cats etc electronically there is no difference these days also have seen 200k on petrol engines with the bores with honing marks still there ,more reliable no difference there either, many more diesels breaking down due to the introduction of sulphur free or low fuels and a lot less lubrication quality in the diesel fuel these days many ijection pumps are breaking down at anything around 700pounds plus fitting on average, diesels do have sligtly better fuel consumption but diesel fuel is more exspensive and when diesels break the parts are loads more money sorry to go on