Not sure what your BMW Turbo does? Not sure if it's working at full capacity? If you need a repair or any advice regarding your BMW Turbo then make sure to speak with us first to save hefty price tags!
The turbocharger on a car applies a very similar principle to a piston engine. It uses the exhaust gas to drive a turbine. This spins an air compressor that pushes extra air (and oxygen) into the cylinders, allowing them to burn more fuel each second.
There are multiple reasons that can cause a turbo to fail or "blow" and all of them can easily be avoided with regular maintenance and treatment. The 5 most common reasons for a turbo failing are:
- Lack of proper lubrication or a delay in the oil reaching the Turbo. Since the turbo is revolving at very high speeds of up to 100k RPM, proper lubrication is non negotiable. It is also important to ensure that oil is delivered at the correct flow rate and pressure. As the speed of the turbo increases, so does the need for oil. If there's a delay in this then the turbo bearings can fail. If your BMW Turbo shaft or bearings has blueing then this could be a sign of oil delay.
- Foreign Material or Dirt in the Lubricating System. A lot of driver's believe that if they drive engines with dirty or contaminated oil then the Oil Filters will remove any foreign matter before the oil reaches the engine, however, this is a costly mistake. All of these materials can cause damage to the bearings when the amount is sufficient to cause bearing wear and bearing-housing bore wear or if the particles of dirt are large enough to block the internal oil passages of the turbo so causing the unit to become starved of oil. The turbo bearings are most likely to fail before the main engine bearings, simply because the turbocharger rotates at much higher speeds than the engine.
- Oil Break-Down. Lubrication is a very important part of the engine and although modern oil technology has gone a long way in providing good oils, we still have two basic problems to contend with:-
(a) Oil deterioration: The high temperatures that are present in modern diesel engines can cause oils to crack or break-down. This action produces carbonaceous (tarry) materials, which stick to the engine rings and cause other troubles. Oxidisation is caused by the hydrocarbons in the oil mixing with the oxygen; this produces organic acids of which there are two main types: those with low boiling points and those with highly corrosive.
These products are responsible for several of the problems on diesel engines and turbochargers. If the acids are al-lowed to become concentrated, they will attack the bearings etc., causing pitting and subsequent failure. Also they react to the remaining oil to form sludge, this is then deposited throughout the engine, particularly in the filters aggravating the turbocharger oil supply. Heavier oxidation causes hard varnish to appear. Where sludge is allowed to accumulate in the oil systems, as this passes through the turbo it is thrown by centrifugal force from the rotating shaft against the walls and internal surfaces of the bearing housing where it can stick and impede the free oil flow. In time the build-up will cause problems with oil drainage, resulting in oil leaking from the turbine end of the unit. If this matter is allowed to accumulate on the turbine side, the heat will cause a baking to take place and the result is usually unbalance in the turbocharger system.
(b) Outside contamination: So far we have briefly looked at oil break-down caused by changes in the oil, usually caused by its exposure to heat and air. However, we must also consider other agents.
Amongst these are the products of fuel combustion, such as ash, soot, the un-burnt heavy ends of the fuel and water. All these elements cause oil contamination. The engine itself contributes to oil break-down in that tiny metal particles produced by wear and tear will either pass through the oil ways into the turbo or oxidise and hasten deterioration. Finally, foreign matter from outside the engine, such as dust and dirt, enters the cylinders through the air intake system.
- Foreign Material in Exhaust or Air-Filtration Systems. Any material, which enters these systems is, without doubt, going to damage the turbocharger and could damage the engine. As a turbocharger is a precision instrument its vulnerability will become instantly apparent the first time any particles go into the casings; damage will be to the wheels which could cause pieces of aluminium to go into the engine, resulting in engine piston, valve, liner and, possibly, crank shaft damage.
This type of material will vary tremendously from dust in the air system to engine valve fragments in the exhaust system. It should also be noted that if any foreign body stays in these systems, the turbo will react with possible loss of power, black smoke, excessive oil usage and leakage and damaged wheels.
- Materials and Workmanship. Only quality assured materials are used and constant quality checks are made on both material and workmanship to meet the stringent OE specifications. The turbocharger is probably the most misunderstood component on the engine, and it is this lack of knowledge by the owner that makes turbocharger service a very difficult area to work in. As we have seen, a turbo will increase a given engine power by about 30%; it will not change any operating characteristics of the engine, it will only do what the engine tells it to do. The source of power for the turbocharger is exhaust gases produced by the engine and this power is controlled by flow, pressure and temperature. If there is an engine malfunction or an abnormal working condition in the engine, the turbocharger will not overcome this, it is more likely to emphasize the problem. From this it follows that replacing a faulty unit with a new one will not always solve the problem. If we are in any doubt at all, we should consult the original equipment engine manual.
If you are unfortunate enough to have your BMW Turbo fail then this can be a costly repair. The average price for new BMW Turbo ranges from £2,500 upwards!
At MBM Autohaus we can provide you with a full re-manufactured BMW Turbo including all other necessary repairs (oil feed pipe, new oil filter, oil change and engine breather if required) for the fixed price of £750 depending on your car's model.