Wheel balancing will sort you out

Qn: I have two cases on my Toyota Corona (Kibina).The signal for over drive (O/D) keeps blinking as I drive. The O/D when applied (pressed) when I am overtaking works well. What could be the cause of the blinking? Has it any effect on the overall performance of the car operation system?

A blinking over drive light (O/D) when you are driving means there are faults in you automatic gearbox electrical control system. These faults are recorded in the memory of the gear box control unit and can be accessed by use of a manual diagnostic procedure or the use of a computerised diagnostic tool. If a malfunction occurs with the speed sensors for number 1 or 2 or gearbox solenoids number 1,2,3 or 4, the over drive light light will blink to warn the driver. In the absence of a diagnostic computer, a repair technician can bridge terminals TE1 and E1 in the diagnostic socket then count the number of flashes which represent a fault code. You can download the detailed interpretation of the O/D light flashes from a Toyota diagnostic fault code chart.

2. Sport rims. What can one do when after balancing the tyres but the car still rolls as if the wheels are in an oval shape, especially when driving below 50km per hour on new very flat surface tarmac roads?
I had never experienced this before with non-sport rims on other cars in the past, but this has happened to me on two cars with sport rims. Should I change rims?
What is the solution?
Felix Basiime

Ans:You need to balance your alloy wheels (rims) on a computerised wheel balancing machine. Testing one of the wheels might confirm whether the others are also damaged and whether you should bother to spend money balancing all of them.

In which case you ought to replace those wheels. Alloy wheels are easier to damage if you drive them hard over pot holes and humps. You should inspect the condition of your tyre tread, unevenly worn out tyres can also cause the sensation of driving on an oval shaped wheel.

Qn: I have enjoyed reading your head to head for the Mercedes W124 and the BMW E34. I own two Mercedes W124s an estate and a sedan which I use to traverse the countryside. I have a sagging roof lining, can it be repaired?
Simon. K

Ans: Your Mercedes W124 roof lining is made of a fabric material lined with a thin layer of foam, like the one which makes foam mattresses. This foam lining is a millimetre or so thick, when you park your car outside, on a sunny day for so many years, the foam disintegrates into small flaky debris. As a result your roof lining sags. Any attempts to glue the old roof lining back are futile as it will not hold or simply drip through the fabric.
A permanent solution is to replace the old lining material with a new one, which is affordable and readily available in Kampala.

Qn: I drive a 2001 Toyota Vista with a D4 engine. It has got 70,000 kms on the clock. The car does not accelerate normally. Can you advise how we can solve the problem?
Robert.

Ans: Your Toyota with a D4 engine (short for direct injection four stroke) has an improved petrol delivery system. Petrol is directly injected into each cylinder through slit like nozzles. This process improves combustion, cold starts, fuel economy and engine output.

The catch is you have to be very diligent to a strict maintenance regime as this sort of engine is sensitive to clean oil, fuel and air supply. Assuming that you have replaced your air filter and spark plugs, I advise that you renew your fuel filter.

It is located in your fuel tank and often ignored by average service technicians because it requires attention to detail during the replacement procedure. The fuel filters are available at major Toyota parts dealers in town.

Qn: My Toyota Corolla AE100 has starting difficulty. Whenever we try to start, the battery runs out. My mechanic has replaced the battery but the new one also runs down. We replaced the fuel pump but there is no change. The car consumes a lot of engine oil. Kayemba, Mbarara
Ans: You need a good car electrician to inspect your car’s electrical system for short circuits or consumers that may be draining your battery when you switch off the ignition and to confirm that your alternator charging capacity is normal.

However, the fact that your car consumes more than normal amount of engine oil suggests that your engine may have a low compression problem.

For an engine to run, it must have enough compression to raise the temperature of the air fuel mixture high enough so that a spark can easily start an efficient combustion process.

If there is not enough compression, the engine will fail to start. An engine low compression situation can be caused by damaged piston rings, cylinders or the cylinder head gasket. The more than normal oil loss in your engine points in that direction. Ask your mechanic to use a compression gauge to confirm this diagnosis.

Qn: I drive a Toyota Noah two wheel drive 1999 model. Problem is the ABS light is on after I recently checked with the mechanic who cleaned the sensors. What could be the problem?
Evans

Ans: Cleaning the anti-lock brake system (ABS) sensors first, is a step in the right direction. Ask your mechanic to physically inspect each sensor and confirm that there is no damaged or broken wheel speed sensor wire.

This is easier done by the diagnostic computer. However, in its absence, a smart technician can test the sensors for continuity to detect a broken circuit. Should this not yield any results you need to test the ABS control unit circuit.

Confirm operation of the ABS relay or circuit breakers by physically inspecting them. Further testing of the ABS modulator requires a computer diagnosis, there are several garages with this equipment in Kampala who can sort you out.

Qn: Do I have to remove the thermostat out of my newly imported Japan used Toyota Mark II 1999 model?
Rojaz

Ans: Contrary to the view of some technicians, all vehicles should have coolant thermostat devices in their engines. The thermostat is a temperature sensitive spring actuated valve which is calibrated to open or close at specific temperatures, to allow or restrict the flow of cold engine coolant fluid from a radiator to the engine.

The engine is designed to run at a specific normal operating temperature beyond which it must be cooled by the cold coolant fluid.
However, the engine must not be cooled below the normal operating range because it will damage the cylinder head and engine block.

The thermostat ensures that the coolant fluid flow is regulated to enhance cooling but avoid damaging your engine. When an engine coolant thermostat is damaged, due to corrosion and delay to renew your coolant fluid, it must be replaced with a new one. A simple test of the thermostat is by dipping it in a bucket of boiling hot water, the spring mechanism should move to open the coolant gate valve. Failure to do so means it has suffered corrosion damage.

The benefits of renewing your radiator coolant every two years include lubrication of your water pump (coolant has glycerin lubricant and anti-corrosive ingredients) and prevention of corrosion of your thermostat, water pump, coolant fluid engine channels and the radiator.

Qn: I drive a Mercedes C200 1997 model with 150,000 kms on the clock. Recently, my engine started misfiring and my regular mechanic replaced the spark plugs, the old ones had engine oil on them. After one week, the problem recurred. The engine is misfiring and spark plugs are wet with oil. Should I get worried, is the engine due for an overhaul?
Bernard Katwesigye

Ans: The oil leaking on your spark plugs is due to the worn out valve cover seals and gasket. Ask your mechanic to unscrew the engine valve cover to access the gasket and seals (around each spark plug) after carefully disengaging the air intake channel right from the air filter housing to the throttle unit.

The mechanic should take care not to damage the delicate breather hose connecting the valve cover to the air intake. You can buy this valve cover gasket and seal kit from all leading Mercedes Benz parts dealers around town. Refit the new seals and that will fix the problem.

Qn: I have a 2002 model Jaguar S type 6 cylinders. When the car starts, the gear lever will shift. I had to force it to get into drive mode. No engine light check. When in drive mode, transmission works fine but my brake lights are not working, is there a connection.
Hanington Muguluma

Ans: Your brake switch is faulty. This is located under the brake pedal. The brake switch once engaged by kicking the brake pedal, sends a signal which releases the shift interlock. This switch has another line which sends a signal to the brake lights. Replace it and you will be alright.