Replacing the oil lines on my 79xlh and was wondering about the routing. Searching other post I see what I think makes sense (out of oil tank into oil pump, out of crankcase-oil return-to oil cooler, out of oil coler to return at tank)It would seem that after the oil passes through motor you cool it before it returns to tank. HOWEVER, on my bike it comes out of oil tank to oil cooler, out of oil coler to oil pump feed, and straight from the crankcase-oil return-back to oil tank. Seems they are cooling it before feeding motor and dumping the hot oil back into the tank. Guess it could be 6 of one and half a dozen of the other, but which way would be preferred? Not sure the cooler does much anyway since if your sitting in traffic theres no air moving through it to col the oil anyway, and if your riding, well, air is passing over the motor to cool it whether you have oil cooler or not. But since I have one, figured I'd hook it back up..just want to hook it up the way that will work best, even if thats just a little bit. &nbsp\\;&nbsp\\;&nbsp\\; Thanks

 

Oil coolers "SHOULD ALWAYS GO" in the return line. Oil should come from engine..........to filter ( if you have one) then to oil cooler..........then to tank.
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ONE OF "THE MANY REASONS" FOR THIS IS...........if oil filter or oil cooler gets stopped up it would starve the engine of oil...........SO put the cooler in the return last before it returns to tank.

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Whoever hooked it up before going into engine is wrong. Not opinion.........FACT!
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Thought it made more sense to have it in return line, not for that reason,which makes alot of sense. In the return line it goes. Thanks.

 

Your 79 is similar to my 81 XLS and the factory oil line routing on mine is set up like this: oil tank main feed to pump, crankcase out to oil cooler, oil cooler to filter, and filter out to tank return. And of course you have the vent that also goes back to the tank. Back pressure from the filter helps keep aeration to a minimun and keeps oil temp cooler.

 

Yeah, thats the way I put it back. Been wanting to add an oil filter, now I know where to place it in line. Thanks

 

He's right.......oil filter last before return to tank. I mis-stated it.
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Tank to pump to crankcase to cooler to filter then back into tank.
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