Tuesday, December 24, 2013

Throttle Body Cleaning and the Importance of it on Classic Rides



"Spray this can of magic snake oil and get better engine response immediately"

Some might immediately dismiss the sales pitch claim from workshops.

But it is actually critical to do this regularly especially on older engines.

For most pre-1991 cars with engines that uses electro-mechanical injection or carburettors, there might be weakened piston rings and valve stem seals that will result the mixture of engine oil and unburnt fuel together with other contaminants that will return to the air intake via the positive crankcase pressure hoses.

The mixture of contaminants returns to the intake unfiltered and will accumulate along the air intake system ( throttle body, intake pipes and manifold walls ). Like the cholesterol choking up the veins of the human body, the gunk reduces the volumetric pressure of the air entering in the combustion chamber. This is due to reduction of the surface area (YES, even if the diameter is reduced by microns, it will affect the air intake volume) and also the surface friction of the gunked up walls of the intake.

Gunked up Throttle Body


By spraying petroleum-based chemicals down the intake system while revving the engine, the actual effect is cleaning the entire intake system, from the intake pipes' walls to the throttle body plates, down to the intake valves itself.

It can be easily done on your own without having to make a trip to the workshop.

This is our recommended method of ensuring a good clean of the intake system for the older Mercedes' engines.

1) Use a reputable brand of petroleum-based throttle body cleaner ( It must be petroleum-based so as to mix with the fuel injected for proper combustion when sparked

2) Remove the air filter box to ensure clear view of the throttle body itself

3) Spray 5-6 seconds with the throttle body fully opened ( without turning on the engine )
If you are running KE Jetronic, you may have to depress the air flow flap manually in order to see the actual throttle body.

4) Let it soak for 5 mins

5) Spray the throttle body cleaner around the air filter element to wet it with the petrol-based cleaner.

6) Re-assemble air filter box with element

7) Start the engine (Engine may die on first few tries, restart engine if it dies by holding partial throttle)

8) The wet filter will ensure the throttle body cleaner is transferred to the entire air intake system gradually. This is because the first application on the throttle itself will be sucked in and fully consumed on the first few seconds. The application on the filter will ensure a longer period of cleansing of the intake system.

9) Drive the car around normally to standard operating temperature of 85 Degree Celsius.
(Do drive slow as the engine may cut off if under heavy throttle as the mixture from the filter might wet the spark plugs )


It is recommended to do the throttle body cleansing every 1000-2000 km and the effect will be instantaneous. You will feel the throttle lighter to depress and a smoother engine revving.


If you found this post useful, do share it with fellow classic rides owners!