DIESEL V PETROL - Which is cheaper to maintain and which one is more reliable?

I've driven diesel's for around 20 years and wouldn't have anything else. The best so far for me is Totota.

Regarding diesel oil changes, I change mine once a year - around 18k miles, my cars a W reg Avensis with 125,000 on the clock, I bought it at 12k miles. The soot that discolour the oil is not a detrimental to the oil's performance as the contaminants produced by a petrol engine.

It depends very much on the model of car, and even on the exact version.

In general, there is less to go wrong with an older diesel engine compared to an older petrol engine, and they are built more strongly. So diesels were traditionally more reliable, but used to need more frequent oil changes (as diesel fuel contaminates the oil more quickly).

With modern cars, the amount of electronics on both petrol and diesel engines means there is little difference in reliability, while improvements in oils mean that there is little difference in the requirement for oil changes.

Hence it comes down to the individual service parts necessary for any particular car - items like spark plugs (for petrol) heater plugs and (if fitted) particulate filters (for diesel), oil and filters (for both).

You need to look at the cost and the service frequency for all these items to calculate the maintenance cost.

diesels are much more reliable than petrol engines

a service costs about 20% more but mile for mile it works out cheaper. i drive an x type and can get up to 60 mpg the same car with a petrol engine returns only 28 at best.

diesels will cover more than twice the miles without any problems at all around 250,000

Modern diesel engines are the way to go; especially the best ones made by VW/Audi and Peugeot. You get the best of both worlds; my 1.9tdi Golf does the same mpg as a good 1.2 petrol, yet has twice the power and three times the torque.

Running costs are no more than petrol overall; some extra costs, but some reduced ones. As for reliabity, my friend's Audi 80 tdi has done over 270,000 miles with no major problems.

i have worked in the motor trade for 19yrs and the diesel engine has come a long way the newer cars are very refined and very reliable and are a joy to drive as for maintenance there not that different from petrol, filters oil and cambelt when due being the main things in common, servicing costs etc depends on the manufacturer so its a bit difficult to be precise.i have owned two diesel cars now and will be buying diesels from now on.

I live in America, so the only diesels we see are usually large trucks and things of that nature, but a diesel engine is a diesel engine I suppose. I have seen many, many diesel trucks with 300+ thousand miles on them and they are not that high maintenance. They don't even have spark plugs to replace like gasoline engines. Thats all I can say from my experience, hope it helps!

Nowadays there's not that much in it. Diesels used to be a bit cheaper to maintain, but now they're so highly tuned with huge turbos and ultra high-pressure fuel delivery systems compared to regular petrol engines, in terms of servicing costs and longevity, they're about the same.

Any car engine that's well maintained should last over 200k miles these days.

Diesel engines have less to go wrong, the way it works doesn't require spark plugs, timming etc... Tune ups are further apart as well.

I've had a 405 TD that was 10 years old, the only work on the engine was replacing the glow plugs which help it start.

Just be carefull in very cold weather as diesel freezes. It should be OK if kept in a garage. I'd stay with pertrol.