This is a hard question to answer, in that an engine is only "any good" if the vast majority of units produced will operate faultlessly for at least 5 years/150k miles. So with a recently produced or modified engine, you don't know.

Legislative changes have generally had detrimental effects on diesel engine performance and longevity and the rapidity of these changes (eg. Euro III to Euro IV and beyond) has caused hurried and botched developments from many makers.

Examples which come to mind are DPFs with fluid burnoff agents, VAG's 2.0 PD diesel engine which required several re-works to get the balancer shaft and oil pump drive to work reliably and of course, Mazda's hopeless attempts at designing a DPF system utilising additional fuel as a burnoff agent. This last fiasco resulted in a sump full of diesel for some users.

So, you're in difficult territory. My solution, for what it's worth, is to buy an old engine design with a proven track record. You won't get the refinement or possibly the ultimate performance of the latest model, but compared with a major failure, does it matter?

I'd far rather have an engine which works reasonably well all of the time than...

I'll stick to my VAG 1.9 PD engine type AWX.

659.

I noticed your priorities list features "grunt" 3 times. The 1.9 PD should do nicely - mine grunts beautifully.

Edited by 659FBE on 25/07/2010 at 17:48

I've currently got a VW Passat SE 2.0 TDI and I previously had a Touran with the same engine.

with the Passat I've had loads of oil leaks - it's been in the garage for about 4 weeks in the last 6 months and my drive looks a real mess. I've also had the cylinder head gasket replaced under warranty. On the Touran, I also had the cylinder head gasket replaced under warranty.

The Passat uses lots of oil (not all through leaks!) and I know other people with the same car with the same problem. I also know people who have had none of the problems I've experienced. I don't know why some of these engines are oil thirsty and others aren't.

So far I'm very happy with the 2.0 CR diesel (170 bhp) in my Octavia vRS: much more linear in acceleration than the PD and just as much 'grunt' (in the desirable sense of that word!).

But mine has done only 15,000 miles and as 659 rightly says above we don't know yet how long-lasting it will be. A good sign is that so far CR engines don't seem to have had DPF problems.

If you're buying new or nearly-new and likely to keep the car for 3 years or so, you'll do very well with this engine. If this is more of a long-term purchase, I'd agree with those who would steer you towards BMW (if you can afford one) or Toyota (if you can't).

Japanese diesels don't seem to be quite as reliable as their petrol engines (there have been some horror stories on here about the Mazda 6 diesel and a few problems with Hondas) but Toyota should be OK.

335d