Which part? Lots of parts in that picture. If it's the shinny piece of brass with 2 airlines and wires. It's you engine fan solenoid.
well you got so much in that picture, and nothing specific, so, i see a radiator hose, air lines, an engine,?? circle the part (or put your finger on it) that you need information about, that would help a lot.
It's in the new driver's forum so he may be asking about that big noisy thing under the hood that leaks oil and has a fan on one end.
Darn engine, always marking it's territory in a sort of fruedian weakness around Cats... HE HE HE HE...
Maybe Mack E5 knows whatsit to go with the whatchamacallit but it will be a while while he hunts up a roundtuit. Those engines are pretty hot. He he.