turbo charger faqs

Q: What is our 20 Point On Vehicle Turbocharger Health Check? (check with AAA GB about their turbo check is their check 20 points? If not can they share)
A: We have designed a 20 point check for your turbocharged vehicle to give you an idea of the “health” of your turbo and what you can do to prolong its life. Contact us to make a booking where we’ll take approximately 15-30 minutes to cover all the ins and outs of your turbo. We’ll provide you with a print out of the report so you can analyse it or use it to promote the sale of your car.

Q: On a used vehicle is there any action we can take to prolong the turbocharger life?
A: On imports just off the boat, look under the rocker cover. Usually there will be heavy build up of sludge. This is due to slow, cold running without regular lube oil changes. Do not to flush system (this will overload an already blocked filter causing the bypass to open and pass contaminants thru the whole system). The best action is; as soon as able carry out a HOT oil and filter change, and again repeat the HOT oil and filter change within the first 500Km. Always use turbo-rated lube oil. For very contaminated engines this process may need to be repeated more than once. Oil and oil filter changes in turbocharged vehicles should be carried out every 5000Km. Always check your air filter when you change your oil and replace it (or wash it, and re-oil it, if it is a washable type) if you are in any doubt.

Q: Will Engine modifications and big bore exhausts improve my vehicles performance?
A: Many modifications to the engine will increase the performance of the vehicle above the factory specifications. These modifications will introduce greater stress on the turbocharger and may cause premature failure.

One of the most common modifications made to many vehicles is the exhaust system. A larger exhaust system (Big-Bore) is one of the cheapest and easiest methods of increasing an engine’s horsepower. This reduces the exhaust gas back-pressure and allows an increase of gas flow across the turbocharger. The problem is the original turbocharger was designed to work on that engine with a known gas flow and backpressure. If the gas flow is increased the wastegate valve cannot spill enough of the gas flow and the speed of the turbine rotor shaft increases, resulting in an over-speed / over-boost situation. An overspeed will result in premature turbocharger failure. This will often be seen in the form of thrust bearing failure (overloading); Compressor wheel failure (over-speeding); Shaft breakages (pulse shock waves).

Other modifications such as computer chip enhancements can cause over-fueling, which may result in fuel still burning when the exhaust valve opens. This causes excessive thermal loading on the turbocharger. After market boost controllers and actuator bleed off valves by their very nature can allow over boosting (overspeeding), which will cause premature turbocharger failure.

Q: I have oil leaking from hoses and joints on my turbo. Is it due for service?
A: One of the most common causes of turbo ‘failure’ is an oil leak from the turbo and/or air pipe work between turbocharger and engine. Note that most engines vent from the rocker cover into the air intake line, which runs between the air cleaner and turbo. Normally this complaint is not caused by the turbo but is caused by a blocked air cleaner or heavy breathing from the crankcase. Remove the intake line to the turbo. If there is oil inside the hose then the oil is coming from the breather. If this type of leakage occurs and the engine is fitted with a charge air cooler the oil will block the air side of cooler and compound the problem. This must be removed and cleaned after the cause of lube oil contamination is corrected.

Q: Why is my turbo noisy? It has a horrible screeching noise coming form it when I accelerate.
A: Turbochargers are often blamed for being noisy when in fact it can often be an exhaust gasket vibrating between 2 faces. The multi-layer steel shim type gaskets can, when a flange warps or becomes loose, vibrate between the clamped surfaces causing a screeching noise. This can be hard to diagnose, but will normally start abruptly under acceleration as the turbo boost pressure increases. As the boost increases so does the exhaust manifold pressure stressing the gaskets. If a manifold is warped or has a loose bolt/stud the pressure forces its way past the gasket causing it to vibrate. The biggest differences between a turbo whistle and a leaking gasket are:

The noise starts abruptly if its a gasket or if its a turbo it will ramp up as the turbo spools up. If its a gasket leak it will most likely have a “buzz” to it where as a turbo will most likely have a smooth whistle. The exhaust gas leak noise is engine speed dependent and affected where the turbo whistle will change tune and pitch with load changes (even if the engine speed remains constant).

Correct diagnosis is important. If in any doubt, please Contact us.