Ask the Mechanic: Why does my engine oil run out so fast?

Hello Paul, whenever I check, the oil level of my Toyota Corona ST190 is always low and the car produces a lot of smoke whenever I switch on the engine.  Sometimes, the accelerator gauge on the dashboard is not relative to the speed when I am driving. It also rises even though I am not accelerating and on a slope while braking (may be 80km/hr), it will display 4 (x1000r/min) if the gear selector is in drive mode. What could be the problem? Joseph 

Hello Joseph, your Toyota Corona ST190 seems to have two engine faults. The first fault or condition is engine oil loss. From what you describe, your engine burns more oil than it ordinarily should. Every engine will burn a very tiny amount of oil during combustion that will amount to less than half a litre after 5,000kms for older vehicles such as yours. 

However, when oil burnt exceeds one to two litres over a 5,000kms service interval or even shorter periods, it means the engine has damaged piston rings and is leaking a lot of oil into the combustion chamber.  This is confirmed by blue smoke and a drastic reduction of engine oil quantity in a shorter spell. This will call for an engine overhaul or replacement of piston rings and crankshaft bearings after inspection of the engine determines the extent of repair needed.

The erratic movement of your engine revolution counter or rev metre suggests a problem with your engine throttle potentiometer or idle air control valve. This is the unit that controls air intake to the engine combustion system. Air intake enables acceleration or idling. When the throttle potentiometer or the attached idling air control valve are dirty or clogged with deposits, the throttle valve could get stuck, hence causing erratic acceleration even when you are not stepping on the gas (accelerator) pedal. 

A qualified technician should dismantle and inspect or service this unit so as to fix the problem.

What is causing this persistent ABS fault?

Hello Paul, I drive a Mercedes Benz ML 320 model 2000 and it has been a reliable car so far. Lately, however, it has developed a persistent ABS ETC fault. The fault lights display on the dash board and when I brake, the pedal rumbles intermittently. A mechanic has advised me to replace the ABS pump which is likely to have failed. The cost of this part is horrendous and I would like a second opinion before I commit. Jonathan.

Hello Jonathan, the Anti-Locking Brake system (ABS) on your Mercedes is designed to work with other components or control modules under the ESP - Electronic Stability Programme. This integrated system includes the engine control module, TC - Traction Control module, instrument clustre module, transmission and transfer case module, etc. These systems are linked by an automotive high speed data transfer hub or network called CAN BUS. 

A break down at any point of this network will be picked up by all the control units on the network as such anyone of them may seem to be faulty. 

Before you write off or attempt to replace the ABS modulator, it is prudent that you find a good Mercedes technician who will follow test steps to test the CAN BUS network and isolate where the faulty component is.  

Whilst the ABS controller is susceptible to damage from a leaking window washer reservoir, sometimes the fault you describe can be caused by the ETC control module. 

A correct diagnosis is necessary to avoid buying the wrong part.

What causes my car to smoke in the morning?

Hello Paul, although I have just serviced it, my Toyota Landcruiser Prado 4.7 petrol, releases a lot of smoke in the morning while driving from home. What could be the problem? Karim 

Hello Karim, please observe the colour of the smoke. It is also important to confirm whether the exhaust continues to bellow a lot of smoke even when your engine attains the normal running temperature of above 80 degrees centigrade. Your car must produce smoke as a by-product of the engine combustion process (burning of the fuel air mixture). The quality (colour) and quantity of smoke will tell a lot about the working condition of your car since the colour of smoke will be different according to the different faults in your engine. 

For example, blue smoke is often caused by broken piston rings or damaged valve stem seals which allow engine oil to infiltrate the combustion chamber and get burnt with the fuel air mixture.  Given your recent engine oil service and the suggestion that the smoke is only excessive shortly after cold engine starts, I think your car produces black smoke. Excessive black smoke from your exhaust is often caused by the presence of an imbalanced fuel-air ratio with more fuel than air (running rich) in the combustion chamber. 

There are several causes of this, such as excessive buildup of dirt in the air cleaner and failure of the throttle valve to open fully or stick due to the buildup of soot which prevents free and prompt engine air in flow and the buildup of appropriate fuel air ratios. On the other hand, leaking or malfunctioning fuel injectors may deliver too much fuel while failure of engine management components such as the oxygen sensors will cause a delivery of more than enough fuel. 

Some of the above faults or features may occur regardless of whether you have carried out the routine engine oil and filter service or not. 

In case your exhaust smoke is black but reduces when the engine is hot, it may be because the engine’s cold start idling revolutions slow down after the engine warms up. This, however, does not negate the need to rectify the cause of the smoke.

My Toyota Noah stops while turning

Hello Paul, I own a Toyota Noah which stops suddenly when trying to negotiate a corner. What could be the cause? Tukei

Hello Tukei, you may have a leakage of unmetered air from the air intake pipe between the air mass sensor after the air cleaner and the engine throttle. Unmetered air intake will distort the fuel air ratio as regulated by the engine management system. 

This will cause erratic running or engine stalling (stopping suddenly) when you load it during steering or switching on other accessories such as air conditioning. Another reason for engine stalling when you load it can be due to loss of power caused by a dirty air cleaner element, worn-out spark plugs or a clogged dirty fuel filter. 

Rarely does a dirty throttle assembly impede free movement of the throttle valve and air intake, causing a drop of engine power which leads to stalling.