I am working on a 2005 Yamaha Bruin 350 4x4. I have all the parts for the oil cooler system rebuild. When I received the vehicle the cooler was not attached so I am not sure which hose was attached to which side of the cooler/radiator. For this reason, I am unsure as to which hose pumps the oil out of the engine block and into the the cooler. Where the hoses atach to the block, the two ports are stacked vertically (upper & lower), but I do not know which hole pumps the oil out and which one receives the cooled oil. I have looked at some service manuals, but they look conflicting to me in that the inflow/outflow points on the cooler diagram page seem to attach opposite of what the diagram on the service manual page showing lubrication points labels the inflow/outflow attachment points on the block. I know the lines in the diagrams are a little hard to follow, but I do beliece I have read the diagram correctly.

So my question, can someone tell me if they know for sure on this machine which port on the block sends the oil out to the cooler (upper or lower hole) and which one receives the oil back from the cooler?

Thanks for your time & any answers

 

Can't see it mattering all that much. Parts book drawing shows both oil inlets on the radiator being at the bottom. So there is no thermosyphoning going on, oil just runs from one side to t'other, and out again. Drawing also clearly shows long pipe going to top union on engine.

 

Thanks for the reply. I guess my concern is that I am using an aftermarket cooler (B&M 70298) and their installation instructions require the cooler inlet/outlets to be on the top of the cooler rather than the bottom. However, I think I was looking at an oil flow diagram from a different service manual as I have now found one that shows the oil flow consistent with the one suggested in the oil cooler diagram.

Thank you very much for taking the time to respond. It was very helpful and led to my discovery of the correct (I believe) information.