Most turbo and injector problems give you plenty of warning, and many can wait for a workshop booking. A few need you to stop right now, for your safety and before a repairable fault becomes a destroyed engine. Here's how to tell the difference.
STOP NOW: pull over safely and switch off
Smoke or flames from the engine bay
- Pull over as soon as it's safe, switch off the engine, and put the handbrake on.
- Get everyone out and move well away from the vehicle, upwind and behind a barrier if there is one.
- Don't open the bonnet fully. Fresh air feeds the fire.
- Call emergency services ( 112 from a mobile phone, 10177 for ambulance and fire, or 10111 for the police ).
- Only use an extinguisher if the fire is small and you can do it safely, aimed through the gap at the front of the bonnet. A vehicle is replaceable. You aren't.
A strong smell of diesel, or fuel visibly leaking
Leaking diesel on a hot turbo or exhaust can ignite. Spilled diesel also makes the road dangerously slippery, especially for motorcyclists. Stop, switch off, and don't restart. Have the vehicle towed.
The engine revs up on its own and won't respond to the accelerator (diesel runaway)
A failed turbo can feed engine oil into the intake. The engine then runs on its own oil and switching off the key may not stop it.
- Keep it in gear. Don't select neutral. In neutral, the engine can over-rev and fail violently.
- Brake firmly to bring the vehicle to a stop. On a manual, keep it in gear and let the brakes stall the engine.
- Once stopped, get out and move away. Don't restart it.
Red oil pressure warning light
Without oil pressure, the turbo and engine bearings destroy themselves within minutes. Stop and switch off immediately. Check the oil level, but don't restart if the light was on with oil in the engine.
Red engine temperature warning, or steam
Pull over, switch off, and let it cool. Never open a hot radiator cap. Scalding coolant can spray out.
A sudden loud bang, grinding or screeching from the engine, followed by power loss or heavy smoke
This is often a turbo coming apart. Fragments can be pulled into the engine. Stop and switch off. Driving on can turn a turbo replacement into an engine replacement.
A thick cloud of blue or white smoke
That's oil or coolant burning in large amounts, and it may be the start of a runaway. Stop safely, switch off and get it towed.
BOOK IT IN SOON: drive carefully, get it checked within days
- Limp mode or reduced power: the engine is protecting itself. Avoid overtaking, towing and long climbs, and get the fault codes read.
- Check engine light (amber, steady): have it scanned soon. A flashing check engine light is more urgent, so reduce speed and get it checked as soon as possible.
- A new whistle, whine or siren noise: often a boost leak or worn turbo bearings.
- Black smoke under acceleration: a boost leak, sticking VGT or injector problem. Fuel use will rise.
- White smoke on cold starts, or a rough idle: often glow plugs or injectors.
- Oil level dropping between services, or oil in the intercooler pipes.
- DPF warning light: follow the owner's manual. Usually a steady highway drive helps, but don't ignore repeat warnings.
- Hard starting, especially when the engine is hot.
See Turbo Problems and Diesel Injector Problems for what each symptom usually means.
WORTH MENTIONING AT YOUR NEXT SERVICE
- Slightly higher fuel consumption than usual
- A faint ticking near an injector, or black residue around the top of an injector
- A small change in how the engine sounds or pulls
Small changes caught early are cheap fixes. See How to Cut Diesel Consumption and How to Make Your Turbo Last.
Hazards most drivers don't think about
Parking on dry grass
Turbos, exhaust manifolds and DPFs run extremely hot, and hottest of all during a DPF regeneration. Never park a hot diesel on long, dry grass. It can start a veld fire and destroy the vehicle. It's a real risk on farms, at campsites and on game drives in winter.
Limp mode at the worst moment
If the engine drops into limp mode during an overtake or on a busy highway, abandon the overtake, switch on your hazards, move left and get off the road as soon as it's safe. Don't keep towing a heavy load in limp mode.
Towing in the heat
Heavy towing, long climbs and hot days push exhaust and engine temperatures up. Watch the temperature gauge, and fit an EGT gauge if you tow with a tuned engine. Ease off before the engine gets too hot.
Modified vehicles
Tuned engines and upgraded turbos run closer to their limits. Every warning sign above matters more. See Diesel Performance Upgrades: More Power Without Breaking Your Engine.
Carry these in your vehicle
- A fire extinguisher, of a type suitable for vehicles, mounted securely where you can reach it
- A warning triangle, and a reflective vest for roadside stops
- Your breakdown or roadside assistance number
Get it checked by people who know turbo diesels
Turbo Diesel Components supplies turbochargers, injectors and fuel system parts for passenger, commercial and industrial applications. If your vehicle is showing any of these warning signs, contact our team or ask your workshop to get in touch with us.