Hi all. When I blew up my old stock 1600 twin port engine and replaced it with a 1915, my garage (specialist air cooled) had suggested I leave the thermostat and flaps out as in their opinion they were more trouble than they are worth. So I took their advice and I have got to say I have had no troubles since. That was around 10 years ago! However, my bus takes around 20 mins to warm up to around 85C sump oil temp, so on short trips the sump oil temp barely reaches 80C. On longer runs averaging around 3500 rpm my sump oil never gets warmer than 92C. I have a secondary external oil filter and oil cooler fitted. My oil temp thermostat opens at 85C so sends the oil through the cooler only when it’s above that temperature. I have a nicely located flashing LED on me dash to let me know when the oil thermostat is open. I guess (like most of us on here), I have fitted additional 'worry gauges'. Mine are for oil temp and cylinder head temp plus others fitted to keep me alert during longer drives. For me, the more important parameter for sufficient air cooling is CHT (No 3) rather than sump oil temp which has had some cooling on its way down to the sump after doing its work around the engine where the oil temps will be much warmer locally. My main concern with my engine with no thermostat fitted was the potential for excessive water condensation oil contamination forming sludge due to my oil not getting past 100C but I have not seen evidence of that when examining my oil and inside of filler cap plus my catch can for mayo deposits after my oil changes (yes I know what your thinking, very very sad). However, lets face it, if you are changing your oil at least every 3000 miles then I would think you would be draining any excessive sludge out during the oil change. Sorry to go on a bit.......... Scull.
