Description
This is the fan motor for the heavier side of the next-generation platform, where the 336 GC version is a different part. It is also one of the most reliably mis-sold numbers in the CAT cooling catalogue, because half the listings on the internet treat it as a cross-reference for 505-5179. It is not.
What Caterpillar states
505-5180 appears in the Caterpillar catalogue as Motor Group-Piston, with the remanufactured description reading axial piston motor, fixed displacement, hydraulic fan. The Chinese-language catalogue entry uses Cat’s PSF shorthand, which is the same code they apply to piston-slipper-fixed units elsewhere in the range. The parts book item name is MOTOR GP-PISTON. So the type is settled: a fixed displacement slipper piston motor, and its job is to turn the fan, not to control it.
Applicability
Caterpillar’s applicability data attaches 505-5180 to the 336 (prefix GDY, C9.3), the 345 GC (KEF, C9.3), the 349 (LKG and RBY, C13) and the 352 (MGR, C13). There is no 349 GC entry in that data, and no 336 GC entry either. The 336 GC, which runs the smaller C7.1, uses 505-5179.
Cross-reference hygiene: what not to accept
Every one of the following appears in live supplier listings for this number. Each is wrong, and we set them out because a purchasing officer who is handed one of these as a quotation has no easy way to check it.
- 505-5179 is not a cross for 505-5180. They belong to different engines and different machines, and Cat does not list either against the other.
- 512-0949 is a different component family. It appears in supplier titles alongside these two numbers with no Cat data behind it.
- 605-5180 is a typo that has become a listing. There is no such Caterpillar part number in the data we can see, yet it is quoted as though it were an alternate.
- Fan pumps do not belong in a fan motor listing. Some titles carry 524-0924 or 524-0925 next to this number, mixing the supply side and the working side of the circuit in one search result.
The practical rule: a valid cross-reference is one you can find in the machine’s parts book or in Cat’s own applicability data against your serial prefix. Everything else is a seller guessing.
Machine context
The 349 that carries this motor is a next-generation machine with a Cat C13 producing 316 kW (424 hp) net to ISO 9249, an operating weight of about 47,700 kg, main system flow of 779 L/min and a cooling system holding 52 litre. Cat publishes 52 C high-ambient capability on this platform and lists a hydraulic reverse fan as optional equipment, which is the duty this motor is asked to perform.
Diagnosis, briefly
A fixed displacement motor has one failure mode worth measuring: internal leakage. Flow arrives, the shaft does not deliver the speed, and the difference shows up as hydraulic oil temperature. Test the command first, then the supply, then the motor. Our hydraulic fan motor diagnosis guide sets out the sequence, and the pump side is covered in the fan pump diagnosis article. If your machine is a 336 GC, the mating pump is 524-0925; for the 336, 340, 345 GC, 349 and 352 it is 524-0924.
Fitting
Match shaft form, flange and port orientation against the removed unit. Flush if the old motor produced debris and fit a new return filter element. Prime the casing before cranking. Keep the case drain unrestricted to tank. Confirm rotation direction with the fan restrained. Target cleanliness around ISO 4406 18/16/13, the class Bosch Rexroth guidance gives for slipper piston units in mobile service.
Terms
Minimum order one piece. New aftermarket units carry a three to six month warranty as stated on your proforma invoice. Bench tested and photographed against your order before the wooden case closes, delivery 5 to 8 working days from payment subject to stock. Send the machine serial prefix and we will confirm the number before invoicing. The full CAT range is under Caterpillar hydraulic fan motor.
