Something I have been pondering since having the external oil cooler fitted was how do I go about changing the oil? Some questions I came up with, - Now the oil drain plug is not the lowest point of the system. I figure I will drain the engine first and check the mesh screen for debree. - Then should I pull a barb off near the cooler to drain the lower part of the system? - Do I need to change the new external oil filter every change? Then with filling it back up. - I am going to fit an in line thermo switch into the system. So if I fill the oil from the engine, it will only trickle slowly into the cooler. Which means the engine will read full but until the oil gets to temp it will not fill the cooler system, but when it does it will effectively drain the engine of oil. - I found a good page from Bergman about new systems and priming pumps to clear the cooler of debree. http://www.bergmannvw.net/Website-New/pages/Engines/engines_accessories-oil_cooler_kits.html Is this the same method I should use to fill the cooler system? Ie. use a priming pump to fill the oil system which contains the cooler first (Which may have to be done both sides of the thermo switch) then fill the engine case above? - And if that is the best method, how thick is our oil do you think? I have found this priming pump on ebay which is for fuel and states that is copes with 'Low Viscosity oil. https://www.ebay.com.au/itm/12V-Ele...838236?hash=item2853b192dc:g:owQAAOSw3W5aoN-I Hopefully that is not a stupid question. Just trying to make sure I don't burn the starter out pumping the extra oil, or somehow only partially fill the oil and then have issues during the first longer drive. Thank you!!!