- Jun 26, 2006
- south africa
hi, i live in south africa and in summer we regularly get temperatures from 20C (low) to 40C (high) and in winter anything from around -3C (low) to 13C (high). i have a Subaru Impreza STI, slightly modified and is used as a daily driver plus some track time. car now has 42000Km mileage and i fitted an oil cooler at ~25000Km. i personally choose to use the Mobil 1 0W40 fully synthetic oil, the oils we have available here are fairly limited and i think its the best of what is out there, although there was talk of Motul becoming available soon. Oil is replaced every 6250Km - 1/2 service, regular service intervals are 12500Km. some friends of mine who run a tuning business say they feel that the 0w40 oil is too thin for the subaru engines and our climatic conditions, so they choose to use/recommend Castrol RS 5W60. i recently fitted oil pressure/temperature sensors and since doing so i've not seen the oil temperature exceed 95C. i have no idea what they were prior to the oil cooler fitment. i also haven't done any track work since then and i'd guess that on the track it would exceed 100C. the 95C was seen during traffic and whilst cruising it will most likely settle ~83C. my question is that at what temperatures would you recommend upgrading to the next level of oil ie: 5W60? or should 'upgrading' your oil be based on other criteria? thanks, calvin.