Hyundai Tucson Diesel Problems

The Hyundai brand has developed an enviable reputation in this country for reliability and quality. The brand’s warranty is also excellent, taking away even more buyer anxiety. With that in mind, the decision to go diesel or petrol comes down to the way you use the vehicle.

This applies to all brands, not just Hyundai, but if all (or most of) your driving will be urban or suburban based, then the petrol engine is for you. Yes, you’ll use a little more fuel than the diesel variant, but servicing costs could be a little lower and you’ll avoid the modern turbo-diesel’s biggest downfall; a blocked Diesel Particulate Filter (DPF).

The DPF is an emissions device that traps the soot from the diesel engine and burns it off at a later date. The problem with that is that the DPF can only burn off the soot and regenerate itself if the engine (and exhaust system) gets to a temperature high enough for this to happen. In urban running, that doesn’t just doesn’t happen, at which point the on-board computer will either try to force a regeneration (not always successful) or the DPF will have to be manually cleaned or even replaced (and that’s costly).

The bottom line, then, is that a turbo-diesel (even a modern one) is only for you if you will be driving the car at highway speeds for at least half an hour at least once a month (once a fortnight is better). If that’s how you use a car, then the diesel should be okay; if not, it’s petrol every time.

It sounds very much like there’s a blow-by problem with this engine. The pressure created by the combustion process is somehow getting past the pistons and into the crankcase, causing the dipstick to leave its tube and blowing oil all around the engine bay.

Blow-by is often caused by worn or broken piston rings or a damaged piston itself. But modern turbo-diesels are also prone to problems with their crankcase ventilation and emissions-control systems which can become full of gunk and not allow the crankcase to breathe properly. At which point, the same symptoms can occur.

A mechanic will be able to do some tests and determine what’s causing the pressure build-up inside the crankcase. If it’s internal wear, a rebuild may be required. But if it’s a build-up of crud inside the emissions-control systems, a manual disassembly and clean might be required. Either way, your car’s warranty might cover you for this, so the Hyundai dealer is your first port of call.

Both the petrol and diesel engines available in the current-generation Tucson have enviable records and reputations for reliability and longevity. Perhaps the factor that will ultimately sway your decision will be the driveline layout, because the all-wheel-drive version of the Tucson is available only with the turbo-diesel or turbo-petrol engine; the normally aspirated engine is available only in front-wheel-drive. To be honest, both the turbocharged 1.6-litre petrol and the turbo-diesel are the natural choices, and the non-turbocharged two-litre petrol engine is very much an also-ran in this model line-up.

That covers the Hyundai Tucson petrol vs diesel debate on a driveability basis, but in other aspects, the question is harder to answer. The petrol turbo is known to be a reliable unit but, in reality, the turbo-diesel probably suits this style of vehicle better with its relaxed feel and effortless nature. That said, if you’re only going to do suburban miles, then rule the diesel out as modern, common-rail diesels with their DPFs really don’t like that type of use. Unless you’re going to drive a decent distance at highway speeds every couple of weeks, the diesel can wind up costing a lot more to maintain.

Even used properly, a diesel engine can be costlier to own and service in the long run and, in the case of the Tucson’s unit, there have been reports of black sludge forming in the intake system, caused by a combination of soot and oil mist which are by-products of the engine’s emissions control. In extreme cases, this black ooze needs to be manually cleaned and that’s a big and expensive job.

But, to confuse things even further, the only transmission available with the turbocharged petrol Tucson is a seven-speed double-clutch unit. Hyundai’s seems better than a lot of such transmissions out there, but many feel this technology is less than perfect and some owners avoid these transmissions at all costs. The turbo-diesel Tucson, in contrast, uses a conventional automatic.