Roger Lee Posted May 31, 2021 Report Share Posted May 31, 2021 This is why during a hose change I relocate the oil return hose from the bottom of the engine back to the oil tank. FD has it doing "S" turns in back of the engine and into a straight oil tank fitting. I'm not bending this hose in the picture. That is its natural state when it was removed. I turn the hose to come out the side of the engine between #2 & #4 cyl. and then replace the straight tank fitting with a 90 degree fitting. I rotate the tank a bit too. The reduced radius hose in the picture causes oil to slow and cause other issues. I always add a spring in the hose that comes off the passenger side oil cooler and makes a 180 degree bend back into the oil pump. The SW and LS have an issue here. The LS has it coming off the thermostat. The same thing happens to this hose and when this oil flow slow down then temps increase and flow to the engine isn't what it should be. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted May 31, 2021 Report Share Posted May 31, 2021 Just like I was one of the first to do a hose change, I think I was one of the first to start switching the older airplanes to the routing Roger mentioned after seeing it from the factory on a later CTLS. Having the return line like that may increase oil temperature because the oil stays in the crankcase a little longer, it likely won't effect flow to the engine. Here is the reason, the supply for the engine and the return are two separate actions, The only way the return line can effect flow to the engine is if the restriction depletes the level of the oil in the tank to below the pickup for the oil supply. If this happens the engine will not run much longer. In all honesty if the return line is restricting the flow of oil from the engine any at all the tank would eventually be depleted of oil, as it would build up in the crankcase. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted July 12, 2021 Report Share Posted July 12, 2021 I just did a hose change a few weeks back. Rotax has changed their oil hose again with a new part number. It seems to be more resistant to kinking in the bend radius. The down side is the price per meter went up quite a bit. Quote Link to comment Share on other sites More sharing options...
Danilo209 Posted March 25, 2022 Report Share Posted March 25, 2022 This is super informative. Im fighting high temps like crazy now and this is a good spot to start. I'm always on or near the red on regular pattern work. Quote Link to comment Share on other sites More sharing options...
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