Hello Paul, my Mercedes C200 has been parked for four years and I have been advised to flush the engine. Apparently the oil has become thick and lumpy. Can I flush it at a petrol station?


Hello George, I have my reservations about the traditional flushing of engines. Before I share my concerns, let us understand why flushing of the engine is done. Engine flushing is the cleaning of internal engine sludge or dirt using a mixture of kerosene or diesel (automotive gas oil) and oil run in the engine for a few minutes.

Sludge is when your engine oil forms a solid or gel at engine operating temperatures. Sludge is usually a result of intrusion of water or excess blow by gases in the engine oil, which can can happen due to a failure of the crank case ventilation or engine cooling system.
Many times, sludge develops when you use cheap or counterfeit engine oils that are not designed or blended with sludge inhibitors.
Kerosene and diesel are more corrosive and can separate some sludge from metallic surfaces and break it down for dispersing. While this procedure may clean some sludge inside the engine, I have my doubts about its appropriateness and effectiveness.

Engines are designed to be lubricated by engine oils of specific viscosity (oil thickness) and performance grade. Altering that recommended viscosity and oil grade by introducing a blend of kerosene or diesel with oil poses the risk of running the engine, albeit for a short time, without adequate lubrication and protection of sensitive metallic engine components in the valve train and crankcase against metal surface sheer or damage. The kerosene or diesel blend with motor oil will damage rubber seals in the long run.

It may also not be easy to fully clean out the flushing oil after its use, remnants of which will contaminate the new engine oil you intend to use for a longer service interval. I would suggest you consider opening the crank case or sump to clean it and the oil pick up tube.
Buy a good mineral engine oil product that is designed with good sludge dispersant additives, run it for a few kilometres, drain it and change the filter. This should sufficiently and safely clean your engine while protecting against further sludge build up.
Over the next couple of drain intervals with a good oil product, your engine should become cleaner.

Hello Paul, I drive a Caldina GTT and lately I am disturbed by the overdrive and check engine light which show up on the dashboard at the same time in the evening. They keep blinking and sometimes the vehicle does not move smoothly. I have to first stop and restart the car for these fault lights to disappear. After driving for a while, they sometimes reappear. However, these fault lights do not appear in the morning. Can I get your advice before going for a computer diagnostic check? Kiwanuka

HelloKiwanuka, the check engine and overdrive lights on your car’s dashboard are flashing or blinking because there is an emission fault and transmission fault recorded by the engine computer and transmission computer respectively. The engine fault could be caused by one of the engine management sensors such as the oxygen sensors, throttle position sensor, throttle position or knock sensors.
On the other hand, the flashing overdrive light could be a result of an electrical fault logged in the transmission computer. It saves time and money to get a computer diagnosis which will read the relevant control modules to pinpoint the exact fault. It is possible for engine and transmission faults to manifest at certain times of the day which are unique to certain driving conditions.
For instance, an evening drive might be warm, in traffic jam, driving uphill all or one of which conditions might trigger the performance symptoms which switch on the warning lights to flash.

Hello Paul, my car’s brakes overheat even when I drive for short distances. The mechanic has tried to replace the brake pads, discs and calipers but the problem persists. What can be done?


Hello Ronald, a car’s brakes can overheat due to several reasons. Your mechanic may have started to tick the boxes and should complete the list. One of the common causes of brakes overheating is jamming or sticking brake caliper pistons. When caliper pistons jam, they lock brake pads onto the disc even when you are not braking. Sometimes they cause a vehicle to swerve as one set of wheels brakes while another continues to move

This can happen due to corrosion of caliper pistons or a failure of the hydraulic connectors to the caliper, hence jamming or sticking. Whilst your mechanic may have replaced the caliper, the brake fluid lines should be inspected for kinking or restriction due to damage. The replacement brake caliper should be inspected for corrosion damage in case it is a used one. Smoking brake pads and discs will sometimes be a result of leaking brake fluid hoses. These will leak brake fluid onto the hot brake discs and pads and start to burn as well as damage the pads.

Brake hoses should routinely be inspected and replaced where found worn out or on the verge of tearing. Overfilled brake fluid reservoirs can sometimes cause a leakage of brake fluid from the caliper pistons when you brake hard. This will leak onto the disc and pads causing smoke or fire. Aged brake fluid will also cause over heating because its role of cooling the brake system is diminished with the aging brake fluid molecules.