Some disadvantages of NBR are poor ozone, sunlight and weather resistance as well as limited high temperature and flame resistance. For higher temperature resistance, a much better material to use is Silicone. 

Rubber covered

Choosing the wrong materials for an oil seal may result in premature wear, lip hardening, cracks, swelling, and subsequent expensive damage to the machinery in which the seal is used. It is therefore vital to gather all relevant data and consult with experts before purchasing to match the right type of oil seal with your application.

Various machines have different components that, when combined, work together as a whole. The equipment will not last forever and will eventually deteriorate through use. The use of mechanical lubrication protects these machines from deterioration while maintaining their designed function.
However, using the wrong type or not applying sufficient lubrication can lead to machine damage, equipment failure, and leaks. Therefore it is important to choose the correct lubricant for your machine.

Stuff clean rags into the cylinder bores and all water and oil passages and bolt holes to catch scrapings and dirt.