I have a 700cc Smart Fortwo and it's proven that the engines last longer on the models fitted with an oil cooler. I've got a brand new cooler so am debating whether to fit an oil thermostat at same time. The OE oil cooler is a tiny item, compared to the one I'm going to fit, and doesn't have a thermostat. I reckon a thermostat is a good idea seeing most of my journeys are short local but there are the occasional all day high speed runs on motorways where I think a cooler would be advantagous. What is other peoples opionion ? Thanks.