Bobcat 863 puzzling cooling fan/overheating issue

[obleck]

Hello, I'm a newbie here, but a capable amateur mechanic. I picked up an 863F with a Deutz 1011F in it, and it's a strong machine except it is overheating (250+ when shut down) slowly when at power. I did the following: - Drained oil, which was pretty gunky, did a flush with 50/50 diesel - replaced oil filter - new thermostat (and cap--there was a redesign it turns out) - pulled the engine oil cooler and flushed it - inspected the cooling fan. - cleaned the radiator fins It's all back together except I didn't have enough oil yesterday to refill everything, so more tests today. However-- and this is the really puzzling thing to me: The fan blows air out of the two side vents to kick up dust 5-10 ft away. So it's working. However, it is NOT sucking air through the radiators, but rather there is slight positive pressure (i.e. air coming UP through the radiators). I this normal? What should I be expecting? I would think it should be pulling a lot of air down through the radiators and out the side vents. Everything is sealed, the impeller is turning in the proper direction, and the impeller has a flat bottom that covers a series of holes that come up from the engine compartment so the air can't really be coming from there except for some sort of venturi effect. Where is the air it's blowing out of the vents coming from? How much air should be passing through the radiator stack and in which direction? Thanks in advance

 

[obleck]

Problem mostly solved. After puzzling on this for a while, I finally threw a rag on top of the radiator and it sucked it right down. It appears there is a lot of turbulence on the top side, and it made it appear that there was net airflow coming up, when it was in fact not. Anyway, after these fixes, I ran it up to temp and it stayed nicely at 228F or so and was blowing warm air out the sides just fine. Someone told me that is still high, but I read also somewhere that these Deutz engines are designed to run pretty hot. It could also be that the temp sender is off. Anyone have any comparison temps from an 863?