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Questions that come up, time  and  time  again. Answers that always help.

Here you can  find practical examples for offers, use a functionality of our products.




Refilling motor oil: Can you mix motor oil in the car?


The mixability  of modern motor oils with one another, regardless of the  type, must be possible under any circumstances. It is not always guaranteed that the  average car driver will know which motor oil was used by the  garage in an oil change.


Can a car manufacturer require a certain manufacturer of lubricants and  other liquids for its vehicles?


No! But you can,  of course, always use the  matching LIQUI MOLY product.


Filling motor oil: Can you simply add  more motor oil to a car?


You do not need to be an expert to add more motor oil to a vehicle. Yet there are a few important things to bear in mind:


  • Before the  motor oil can  be added, the  precise oil level has to be established. This takes place using the  dip stick (mostly identified by color in the  area of the  oil filler neck). The vehicle must be on an even  surface. To measure, simply pull out the  dip stick, wipe off any oil, put it back  in and  pull it out again. Now the  precise oil level can  be read and,  if necessary, easily correct

  • On the  dip stick, there is generally a liter between the  marks of MIN. and  MAX.

  • The right oil has to be used. If this is not known, our OIL GUIDE or our technical support by phone +49 731 1420-871 can  help


What happens if you add  too much motor oil?


The oil level of the  motor must always be correct, as both  too little  and  too much oil can  lead  to serious damage of the  motor. you add too much oil, this can  lead  to the  creation of many  air bubbles. These air bubbles are then sucked by the  oil pump and moved through the  motor to the  lubrication points. As air famously does not lubricate, greater wear is generated at the  areas friction to be lubricated, which can  lead  to motor damage.


A further problem of overfilling is increased oil pressure. This can  lead  to seals, which are supposed to keep the  oil in the  mot being  torn from their actual position or damaged and  therefore the  motor becoming leaky.



What does the acronym API stand for?


The acronym API stands for American Petroleum Institute. It sets the  global quality  requirements and  testing criteria of lubricants, such as motor or gearbox oil.



Are petrol motor oil and  diesel motor oil the same?


The question of which motor oil is suitable for diesel motors keeps coming up, again and  again. But the  times in which there were special motor oils for diesel motors are long gone. Modern motor oils fulfill both  the  requirements of petrol and  diesel motors. What's important in the  selection of the  right motor oil is much more the  specification or approval given by the  vehicl manufacturer. If this is printed on the  bottle label, then the  oil can  be used for the  respective motor. Regardless of whether it' diesel or petrol.



What does light-brown sludge on the oil filler cap mean?


If a vehicle is mainly  used for short journeys, this has the  consequence that the  condensation created by temperature differen mixes with the  oil and  does not evaporate. This oil/water emulsion is then deposited in the  entire motor. This becomes visible the  oil filler cap in the  form of light-brown sludge. In order to free the  motor of this, LIQUI MOLY offers the  oil sludge purge.


My oil is gray. Is this old oil?


The color of a motor oil provides no conclusions regarding quality  or age.  There are, therefore, chemical additives that superimpose on the  actual color (amber) of the  oil and  therefore make it appear darker.


After how many kilometers does oil have to be added?


There is no general answer to how often  a motor oil has to be refilled. Oil consumption can  vary greatly even  with motors identical in construction. If there is no oil level control fitted,  the  oil level should be checked every time  you refuel and correspondingly reacted to.



Which motor oil do I need to use?


What's important in the  selection of the  right motor oil is the  specification or approval given by the  vehicle manufacturer, whic can  be found  in the  operating manual of the  vehicle. If this is printed on the  label of an oil, then this oil can  be used for the respective motor. If you are not sure about this, our OIL GUIDE or our technical support by phone +49 731 1420-871 can  help.



Check motor oil when cold or warm?


The fill level of the  motor oil is always measured when  it is warm. This ensures that the  motor is in the  temperature range in which it usually is, optimally supplied with lubricant.



Which motor oil should be used for snow blowers?


Fundamentally, the  recommendation of the  manufacturer should be followed when  selecting the  oil for snow blowers. Howeve experience shows that our Special Tec LL 5W-30 covers the  majority of snow blowers available on the  market.



How can I tell that an oil change is really needed?


We keep receiving questions like "what do you think  of a motor oil change after as long as two years?". Without  a sound laboratory analysis of the  old oil, the  car driver cannot assess the  condition of a motor oil by the  color or by rubbing it betwee their thumb and  index finger. When a change of the  lubricant is necessary is decided either by the  vehicle itself (variable) or th change was set by the  manufacturer according to a fixed mileage or age.  In the  case of a variable change interval, the  vehicle tell you when  a change is required. The mileage until the  next  change can  simply be called up in the  vehicle menu. Should a change be prescribed, the  date is usually written on the  oil note  in the  motor compartment or in the  service booklet of the vehicle.



Does it damage the motor if I fill it with the wrong motor oil?


A definite yes! Modern motors are highly complex mechanical assemblies. Due to the  high requirements expected of them the require a lubricant aligned to the  materials and  properties. If it does not receive this, the  increased friction may lead  to motor damage.



Why is my motor oil black again immediately after being changed?


As there are soot deposits in the  oil circuit particularly in diesel motors, but also in petrol motors, the  oil is often  colored blac after the  first few revolutions of the  motor. However, this is no reason to panic, as the  oil is doing what  it should: It is cleaning! While doing so, it is absorbing the  soot deposits in the  motor and  then transporting it to the  oil filter.



How long  is oil good  for?


The minimum durability in small containers is five years – assuming it is stored in a dry place at temperatures between + 5 °C

and  + 30 °C and  is not in direct sunlight. The cellar, and  not the  garage, is ideally  suited to storage.



My vehicle has been converted to gas, which oil should I use now?


Fundamentally, the  specifications of the  gas system manufacturer and  the  motor manufacturer should be observed. If the  veh manufacturer approves more general specifications (e.g. ACEA C2/C3 or C4), then low ash oils according to this specification to be preferred during gas operation. Furthermore, Cera Tec as an oil additive for gas-operated motors is of a fundamental advantage. A dose of 7% to 8% in the  motor oil is optimum.



Does two-stroke oil become separated from the fuel after an extended storage period?


Two-stroke oil dissolves fully in fuel and  does not become separated even  after an extended storage period.



My vehicle manufacturer says I need to add  a 5W-30 oil. Is this correct?


What is decisive for the  selection of an oil is the  quality  and  the  manufacturer guidelines, not the  viscosity. This information ca be found  on the  container label. The 5W-30 specification relates only to the  liquid condition of an oil at a certain temperature

is not a sign of quality.



Can mineral motor oils be mixed with synthetic motor oils?


Yes! The mixability  of the  motor oils with one another must be possible in order to guarantee refilling at any time. However –

depending on the  oil added – the  quality  or the  properties of the  existing oil are changed.



Why is the MoS2 low friction 10W-40 motor oil black, sludgy and  looks like old oil?


Motor oil has molybdenum disulfide added to it. This anthracite-colored additive superimposes on the  "normal" color of the  oil



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