Oil pump 320/04186 JCB Dieselmax, genuine

For the JCB Dieselmax 444 and 448 engines: oil pump 320/04186, a genuine JCB part. The card also lists 320/04300.

Low oil pressure does not always mean a failed pump: a blocked pick-up strainer, worn bearings, oil of the wrong viscosity or a faulty pressure sensor give the same symptom. So before replacing the pump, measure the oil pressure with a mechanical gauge and check the pick-up strainer. When the gears and body are worn the pump is replaced as a unit; renewing single parts does not give a reliable result. The pressure relief valve on the pump stops pressure rising too high on cold, thick oil. If the valve sticks open, pressure drops; if it sticks shut, the filter and seals are overloaded. The pump is the key part of the lubrication system; at an overhaul it is measured or replaced. The pump body is aluminium or cast iron.

Specifications

Compatibility

The part is listed for JCB 3CX and 4CX backhoe loaders. The catalogue also has the aftermarket version of this part. Other parts are in JCB Dieselmax engine.

Fitting

Before fitting, fill the pump with clean engine oil so that it does not run dry on first start. Check the mounting face and O-rings, measure the gear backlash and tighten the bolts to JCB figures. Change the oil and filter and clean the pick-up strainer when the pump is replaced; on first start check that oil pressure rises within a few seconds. Fit the pump bolts with thread locker or new washers.