Quote:
Originally Posted by SD1too
What's this about then Gary? I seem to have missed it.
Concerning viscosity, if you think that the ambient temperature in Worthing is going to drop below minus 20°C then get 5W40 oil. Otherwise MG Rover recommends 10W40 for your engine........
Simon
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Yes, the handbook states that 10w40 is the recommended oil for this engine.
However, it should be noted that these publications are now at least a decade old. The handbooks also take into consideration what is readily available at the time.
Today, if you were to key in your engine details and ask companies such as Castrol, Mobil or Shell for their recommended oil for a KV6 engine, they would recommend their 0w40 or 5w40 oils.
It is not just about minimum temperatures on start-up, but also the viscosity from ambient to operating temperature.
Below are various viscosity curves,
above 0 degrees for 0w40, 5w40, 10w40 and I have also plotted 15w40 for comparison, as shown below:
If I were using an engine for shorter runs, I would be looking for an oil to give better protection during the warm up phase from ambient to engine operating temperature. This is because it would spend more time proportionally in comparison to a car used on long motorway runs.
I would choose a 5w40 or 0w40 in this case.