Rover 75 MG ZT ZT-T Diesel CDTi Intercooler O Rings Kit - VITON. PYX100321

These are Viton - so won't swell and will last the life of the car. The reason the O rings fail is because the rubber used is not resistant to fuel / oil and swells - Viton O rings, however, are - so this is a once-in-the-cars-life job.