You can mix motor oil
Some brands may raise eyebrows, yet the reality stands: motor oils can be mixed in many situations. When performing an oil change, it is wise to avoid randomly combining products from different manufacturers. For topping up between changes, it helps to use the same oil that is already in the engine.
Guidance on a roadside top up is practical. If the oil level is low, adding any oil is advisable. In such cases, diesel oil can be used in a gasoline engine and vice versa. Viscosity matters little unless the engine is unusually worn, where a low idle light may illuminate with 15W-50 oil. Adding 0W-16 at that stage is not recommended and tends to be costly.
Impact of the letter grade after the API designation, such as SL, SM, or SN, is not dramatic for upgrading. Generally, the farther the letter sits from the start of the alphabet, the better the performance. Engine manufacturers typically do not quarrel over minor oil grade differences during routine operation.
After a long journey where frequent additions were necessary, it is prudent to perform an oil change. It is also wise to consider the engine oil burner and how the engine handles fuel and oil usage.
The container for engine oil usually shows the API quality level and the SAE viscosity for quick reference.
Coolants what to add water
If only a small amount of coolant is needed, say 100 to 200 milliliters, distilled water or a clean filtered water will do. This is a common practice because when coolant is lost in a closed cooling system, evaporation is the main cause. Other coolant components such as ethylene glycol and additives evaporate much more slowly.
When the liquid loss is more substantial, it is necessary to replenish coolant exactly as the vehicle manufacturer prescribes.
Mixing different coolant chemistries is strongly discouraged. Leading manufacturers maintain strict guidelines because incompatible additives can neutralize each other and reduce effectiveness.
Colour should not be mistaken for composition. In a pinch, it may be necessary to use what is available, but it is best to choose the most modern coolant from a reputable maker. Domestic brands that are commonly encountered include Nord, Felix, Sintec, and Coolstream.
At the first opportunity, the entire cooling system should be checked and refreshed as needed.
It is important to remember that the colour of the coolant does not indicate its actual composition.
Fuel no petrol with diesel
Two fuel types exist: petrol and diesel. They must never be mixed. Within each type, users can select among fuels without worrying about blend integrity to a reasonable extent, as long as the basic requirements are followed. Density differences between gasoline blends are minimal and not a concern for tank compatibility.
Brake fluid
Most modern brake fluids are compatible and can be mixed in various proportions. It is generally recommended to use high performance fluids such as DOT 4 or DOT 5.1 in contemporary vehicles, while DOT 3 is rarely sold today. The only notable exception is silicone based DOT 5, which should never be mixed with glycol or polyester based fluids.
The brake fluid reservoir cap usually carries a DOT designation for quick identification.
More on transmission and other fluids will follow in future installments
- Specific guidance on what to do if diesel is mistakenly used instead of gasoline is explained in detail elsewhere.
- Additional automotive topics can be found in related sections managed by the publisher.