Q: I am planning to buy the Renault Triber but as I understand its engine crank case/sump is made of plastic instead of metal. I have also come across some reports of such plastic sumps getting damaged due to stone hits or rubbing on bumps. Please let me know how reliable and safe this material is for such a critical and high temperature application. A metal sump also helps in dissipating engine heat absorbed by oil which a plastic sump will not do. 

 

Ashutosh Tiwari, Mumbai 

The use of materials such as specially-engineered plastics and polyamides in critical applications, for instance, the engine oil sump in the Renault Triber, is an endeavour of automakers to reduce the overall weight of cars. As a result, the term ‘lightweighting’ is popularly used within the industry in this regard. 

Such materials could offer potential weight savings of up to 50 percent of a component’s original weight, which is quite substantial. While plastic might look inferior in strength compared to metals such as aluminium, these specific materials are carefully engineered and tested to offer a high thermal resistance to the oil’s temperature, as well as resistance to impact from curbs, stones and even if the entire engine drops. 

Some of these materials are glass reinforced and heat stabilised to offer very good flow properties for optimum heat dissipation. They also undergo rigorous testing before being approved for implementation in critical components in road-worthy vehicles that are to be mass produced. 

Hence, these tests ensure that the sump can bear stone and gravel-chip impacts as well as high operating temperatures throughout the life of the vehicle, so as to cause no failures. 

Since you are inclined towards the Renault Triber, we suggest you don’t let the material of the sump guard influence your decision.