GOOD DIESEL, BAD DIESEL

On this page we take a quick look at legendary diesels and more modern diesel engines.

Some diesel engines where very well designed and still plod away regardless, whilst others became well known for less than impressive reasons.

Our info here is a little biased towards the diesel engines fuel system and certainly does not take into the account any details of the rest of the vehicle or machine.

GOOD DIESELS

BMW 2.5 TD/TDS

This engine set new levels for power and refinement during the mid nineties, the sound of this straight 6 was (and still is) rather impressive. Gave bags of power in the BMW 325/525 and Vauxhall Omega but struggled a bit when plonked into a RangeRover. Fitted with the Bosch VP37 pump giving it the ability to run on veg oil/bio diesel without too much hassle.

BMW COMMON RAIL

German engineering delivers an incredibly powerful, smooth and reliable motor. Does suffer from injector issues (as all common rail diesels do) but despite this an excellent engine.

CUMMINS PT

For truck engines the Cummins was king. Gave incredible low down torque and with good mpg. A shame they ruined it by adding electronic control.

DAIHATSU 2.8

Never was a popular engine which is a shame as it was incredibly reliable and took abuse very well. Excellent lugging ability and fitted with VE type pump making veg oil/bio diesel use feasible.

LEYLAND 4.98

The 4.98 engine was fitted to numerous applications including JCB and Leyland/Marshall tractors. A good solid engine with plenty of torque and not too bad on fuel. Essential to keep the anti-freeze mix just right though.

MERCEDES 2.9 (Pre CDI)

This engine found it's way into the Sprinter and SsangYong Musso (though in the Sprinter it generally had the Bosch VP37 pump). A good low revving grunty engine which if maintained goes on and on and on.

MITSUBISHI 2.8 TURBO (4M40).

Although a thirsty engine it proves to be virtually indestructible. Plenty of torque making it ideal for towing purposes. Fitted with VE type pump making it suitable for veg oil/bio diesel though pump seals prone for giving issues. May lack the power compared to the newer 2.5/3.2 DiD but a darn sight more reliable and less costly to put right.

PERKINS

Was the biggest manufacturer of diesel engines (maybe still is?). Although Perkins made many engines of different types perhaps the best where the 3.152 (as fitted into the MF35X and MF135) and the 4.236. These engines still work hard today many of which have never had a rebuild. Less good Perkins engines where the V8 the 6.354 and Prima as found in the Maestro enough said?

PEUGEOT/CITREON XUD7/9 TURBO and NON TURBO

Possibly the first diesel engine to be considered acceptable for car use as at the time it was reasonably quiet and powerful and also pretty darn good for economy, indeed many past clients state far better mpg for this older engine than the HDI. Cam belt replacement at the correct intervals was essential, engines fitted with Bosch fuel system suitable for veg oil/bio diesel.

TRANSIT 2.5 Dl

Many say this was and still is the best engine fitted in the Ford Transit. Although lacking the punch of it's replacement (DuraTorq and TDCI) it is far more reliable and far less costly to maintain. Engines of 1994 onwards generally had a Bosch injection pump making veg oil/bio diesel a viable option. Beware of the 2.5 Dl Turbo as this was cursed with the Epic injection pump (Epic injection pump = Bad diesel).

VAUXHALL 2.0/2.2 (DI/DTL/DTH)

We may divide opinion here but despite the original issues with the injection pump this engine is good. A solid engine and all round good performer. Once the injection pump is overhauled with the latest parts it has a good chance of being problem free for the life of the engine. We see these engines covering over 300k miles and still going strong. Beware though of the engines fitted with the VP44 PSG16 pump!

VW/AUDI

The good 1.9 TDI (90/110bhp) and even better 2.5 TDI (5 cylinder) set new standards during the mid nineties in terms of power. Although looking a little lame compared to newer diesel bhp figures and sounding rather noisy these engines still deliver incredible mpg figures and provide excellent reliability. Cam belt replacement is essential though along with regular oil changes. Fitted with Bosch VP37 pump (EDC) making it a good candidate for veg oil/bio diesel. V6 2.5 TDI's are also a good solid engine though cam belt replacement is ESSENTIAL and the injection pump (VP44) is fragile and costly to service. The PD engine has also proved itself to be quite reliable with reduced noise and higher power ratings available. Whether the common rail VW/Audi engines prove to be as good as there predecessors is yet to be seen.

BAD DIESELS

FORD TDCI
Focus 1.8 TDCI (2001 to 2006)
Mondeo 2.0 & 2.2 TDCI (2001 to 2007)
Transit 2.0 & 2.2 TDCI (2004 to 2007)

Oh dear!
Apart from the problems of:

Injector failure,
Fuel pump failure,
Cam chain jumping,
Dual mass flywheel collapse,
Wiring faults,
ECU problems.

A pretty good engine (ermm!)

ISUZU 3.0

(This applies to the 4 cylinder engine as often found in the late 90's Trooper)

Terrible engine! Despite being one of the first common rail diesels it proved to be a dealerships worst nightmare. Often self destructed and very expensive to put right.
3.1 engine was far better.

JAGUAR 2.0 / 2.2

See Ford TDCI

KIA Sedona 2.9

Fuel system faults aplenty on this engine:

Injector failure (combined with them seizing in the cylinder head),
Fuel pump collapse.

LANDROVER TD5

A vehicle or engine that was either loved or loathed. Personally we found it a let down. Expensive to maintain though fitted with Unit Injectors allowing veg oil/bio diesel use.

MERCEDES CDI

(Controversial we know but if you have experienced a bad case of 'black death' you'll probably agree)

A very good, powerful and smooth engine but suffers from a couple of common issues both which can lead to big repair bills. Glow plug seizures often result in the removal of the cylinder head especially on the Vito. Injector leakages. Lack of a thick copper sealing washer results in blow by of combustion gases, this leads to carbon build up (known as 'black death' in the trade) around the injectors which can seize the injectors in the head and can result in the junking of the engine. One of the first signs of injector leakage is fumes inside the vehicle. Both issues more common on the Sprinter and Vito than other applications.

NISSAN Interstar 1.9 DCI

See Renault 1.9 DCI

PEUGEOT 2.1

Often found in Pre-HDI 406 cars and was cursed with the dreaded Lucas/Delphi EPIC injection pump which invariably resulted in big repair bills.

PEUGEOT 807 HDI

Suffers in pretty much every way as Renault 1.9 / 2.2 DCI but five times worse to work on!

RENAULT 1.5 DCI

The early versions of this engine were pretty awful, common issues included:

Turbo chargers failing (often wiping out the engine with it),
Injector faults,
Fuel pumps collapsing,
Wiring issues,
ECU failures.

RENAULT 1.9 / 2.2 DCI

Injectors seized anyone??

Why oh why did nobody at Renault take science lessons? Put a dry steel injector into an alloy cylinder head, give it a year or so and hey presto you have now got injectors that don't need clamps to hold them in!

Just smearing of antiseize paste and...... well, too late now.

Also suffers from:
Wiring issues,
Turbo charger failures,
Goes through EGR valves rather too often.

TOYOTA SURF (2.4 & 3.0 EFI)

We may well divide opinion but not good engines, overheating for fun, underpowered, thirsty.

WE WILL NOT CARRY OUT ANY WORK TO TOYOTA SURFS!!

VAUXHALL Vivaro & Movano

See Renault 1.9 / 2.2 DCI

1.6 TDCI FORD FUSION / PEUGEOT / CITREON 1.6 HDI

Annoying fault of injector seal leakage
Horrendous fault of turbo charger self destruction