Common rail diesel problems: how to understand and resolve them

Common rail diesels have been with us for many years now, and there’s no sign of their problems abating. Almost all common rail diesel problems are expensive, which makes preventative maintenance a very valuable investment for your vehicle. Since so many of our customers own common rail diesels, Jimmy and I thought we should help you identify and understand the problems regularly encountered — so it’s easier to decide what action to take, at low cost, before things become more serious.

Short answer: most common rail diesel problems — smoke, power loss, rattle, dirty oil, EGR and DPF trouble — come down to deposits and degraded fuel, not worn-out parts. Keeping the fuel and oil systems clean with the right additives resolves over 80% of them, at a fraction of the cost of repairs.

The Usual Common Rail Diesel Problems

Smoke
Power loss
Rough idle
Engine rattle
Dirty diesel engine oil
Oil use
EGR valve problems
Inlet system deposits
Turbocharger failures
Excessive diesel particulate filter regenerations

CRD Fuel Enhancer will restore injectors and avoid common rail problems. Satisfaction Guaranteed.

Simply add CRD Fuel Enhancer to your diesel and common rail injector problems are solved.

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What Causes These Common Rail Diesel Problems — and Why

Diesel fuel quality. Avoid the cheap stuff, and avoid using truck diesel in light common rail engines.
Operating conditions. Lots of short runs, excessive idling, cool operating and light engine loads all contribute to deposit problems in the combustion chamber, exhaust spaces, turbocharger and DPF.
High pressure and high temperature. Common rail injection systems run hot and high enough to degrade the fuel, leaving deposits in your pumps and injectors and lowering the fuel’s lubricating ability. A fuel filter going black is a sign of this happening.
Sticking fuel injectors. Injectors then stick and allow excess fuel through, causing engine rattle and carboning up your EGR valves, turbocharger, DPF, combustion chambers and more.
Piston ring deposits. These let compression blow-by pressure into the sump, with heavy soot contamination of the oil. That pressure is released via the crankcase ventilation system into the air intake, carrying an oil mist that mixes with EGR soot — fouling the throttle body and choking up the intake manifold.

How to Rectify Common Rail Diesel Problems

Three products, used as directed, address the vast majority of these problems at the root cause:

CRD Fuel Enhancer — with every tank

Cheap to use (just 10mL per 80L of diesel). Faulty CRD injectors can normally be fully recovered with CRD Fuel Enhancer alone — its cleaning and lubricity power ensures injectors meter fuel accurately without over-fuelling. It’s even cheaper to use than two-stroke oil, with far stronger lubricity and detergency.

Flushing Oil Concentrate — at every oil change

Cleans the oil system of soot and sludge, and frees up piston rings to tighten the seal against blow-by and oil use. Doing this at every oil change is low cost and keeps the engine cleaner and healthier than ever. Used together, CRD Fuel Enhancer and Flushing Oil Concentrate directly address inlet-system deposits, injector fouling, smoke, injector rattle and power issues.

FTC Decarbonizer — for heavy carbon

If the engine already has heavy coking of the combustion chambers, turbo, EGR or DPF, add FTC Decarbonizer to your fuel. It actively burns off carbon from combustion and exhaust spaces, turbochargers and DPFs — especially helpful where there’s a lot of short-run, idling or light-duty use.

One important exception: if you already have heavy inlet deposits (there may be 2–3 cups of gunk to deal with), physically clean them rather than spraying solvent through the intake and risking serious engine damage.

Used as directed, these three products will successfully eliminate over 80% of all common rail diesel problems.

Got a problem not listed above, or need more detailed advice? Jimmy and I are here to help. For related reading, see our guide on why you usually don’t need to replace your common rail injectors, how CRD Fuel Enhancer works, and fixing DPF regen problems.

Common rail diesel problems: how to understand and resolve them