I have a 2011 Subaru Outback 2.0 diesel (EE20 motor). It has 235000km (146000 mls) on the clock. I have been running Ravenol VMP 5W30 up until now. I have recently had the DPF removed (legal here in South Africa) and am wondering if I should change oils, as the ash content isn't as much of an issue now, and if I can save a few bucks without losing the protection it would be great. Also, in a hot country like ours, should I go up to a 5W40 instead? I change oil every 10000 km (6200 mls).