Key Takeaways
- Loss of power, smoke and new noises are the most common signs.
- Blue smoke and rising oil use point to oil getting past the turbo seals.
- A siren-like whine or grinding needs checking straight away.
- Limp mode is the engine protecting itself, not a fix.
- Several signs together make a turbo fault far more likely.
The most common signs of a failing turbo are a loss of power, unusual exhaust smoke, new whining or whistling noises and a warning light on the dashboard. Rising oil use and slower acceleration often come with them. One sign on its own can have several causes, but two or three together make a turbo fault far more likely.
Below are the ten signs to look out for, what each one usually means and where to find more detail.
Turbo Failure Symptoms at a Glance
| Sign | What It Usually Means | How Urgent |
|---|---|---|
| Loss of power | Low boost from a leak, control fault or worn turbo | Soon |
| Blue or grey smoke | Oil burning, often from worn turbo seals | Soon |
| Black smoke | Too much fuel for the air available | Soon |
| Siren-like whine or grinding | Worn bearings or a wheel touching the housing | Straight away |
| Warning light or fault code | A boost fault has been recorded | Soon |
| Rising oil use | Oil passing through the turbo | Soon |
| Limp mode | The engine is protecting itself from a boost fault | Straight away |
10 Signs of a Failing Turbo
1. Loss of Power
This is often the first sign drivers notice. The car does not pull as it used to, particularly when overtaking or climbing hills. It happens when the turbo is not supplying enough boost, which can be caused by a boost leak, a control fault or wear inside the turbo. Our guide on why a turbo is not boosting covers the causes in more detail.
2. Excessive Exhaust Smoke
The colour of the smoke gives a good clue to the cause.
- Blue or grey smoke means oil is being burned. With a turbo, this is often down to worn seals. See our guide on blue smoke from the turbo.
- Black smoke means the engine is getting too much fuel for the air available, which can happen when the turbo is not delivering enough boost.
- White smoke can be harmless condensation on a cold start, or a sign of coolant or oil getting where it should not. See our guide on white smoke from the turbo.
3. Whining, Whistling or Grinding Noises
A faint whistle as the turbo spools up is normal. A louder whistle, a siren-like whine that rises with the revs, or any grinding or rattling is not. A whine usually points to worn bearings, while grinding can mean the wheel is touching the housing. Our guide on why your turbo whistles when accelerating explains the different sounds.
4. Engine Warning Light
The engine management light is a catch-all warning, but it often comes on with turbo problems. Common codes include P0299 for underboost and P0234 for overboost. A code reader or a garage can tell you what has been recorded. Our guide on how to test if your turbo is working explains how to read and use these codes.
5. Increased Oil Consumption
Turbos run on engine oil for lubrication and cooling. If the seals wear, oil can pass into the intake or exhaust and be burned. If you need to top up the oil more often and there are no visible leaks, the turbo is a likely suspect.
6. Slow Acceleration and Turbo Lag
Some delay before the turbo comes in is normal, but it should not get worse over time. If there is a longer pause before the power arrives, or the power comes in unevenly, the turbo may be struggling to spool. A stuck wastegate or a sticking actuator can cause the same feeling, as can a blocked air filter.
7. Unusual Boost Readings
If your car has a boost gauge, or you can see boost in live data, it is a useful early warning. Consistently low boost suggests a leak or a worn turbo. Boost that spikes higher than normal suggests the wastegate is not opening as it should, which can put the engine at risk.
8. Oil Around the Turbo or in the Intercooler
Oil on the outside of the turbo, or pooling inside the intercooler and its pipes, can mean the turbo seals are failing. Oil in the intake also reduces the efficiency of the intercooler. Our guide on oil in the turbo intercooler explains how to check.
9. Worse Fuel Economy
When the turbo is not working properly, the engine has to work harder for the same speed and uses more fuel. A steady drop in miles per gallon, with no change in how you drive, is worth looking into alongside the other signs on this list.
10. Limp Mode
Limp mode is the engine protecting itself. When the engine management system spots a serious boost fault, it cuts power and limits the revs so the car can still be driven slowly. It may clear after a restart, but the fault that caused it will still be there.
What to Do Next
Several of these signs can be caused by faults that are not the turbo at all, such as a split hose, a faulty sensor or a blocked DPF. Our guide on how to tell if a turbo is bad explains how to rule these out.
If the signs are severe, particularly grinding noises, heavy smoke or limp mode, stop driving the car where possible. Our guide on whether you can drive with a blown turbo explains the risks.
Get In Touch
If you notice any of the signs above and the turbo needs replacing, we can help. Here at Essex Turbos, we supply reconditioned turbos, remanufactured and new units for all major car and van brands, each with a one to two year unlimited mileage warranty.
To find the right turbo for your vehicle, simply get in touch today.