Under the guidance of laws and regulations, the emission level of vehicles has been continuously upgraded and occupied the mainstream in the national five. Today, with the advent of national six, a large number of truck with national three and national four emission levels are still in operation. Recently, my brother Jun of Wuhan and I talked about a common mechanical failure of the SOFIM 8140 diesel engine of Guosi Iveco (produced in 2016).
Card friends who are familiar with SOFIM engine should know that this diesel engine adopts the structural form of aluminum alloy cylinder head, overhead camshaft, timing belt drive and integrated arrangement of accessories, and has maintained the leading position in the technology of mechanical parts at the same level for many years.
An accessory box is arranged on the left side of the front of the engine body. The driving and driven gears of the accessory box are also the gears of the oil pump. The power steering pump and high-pressure oil pump are driven by the accessory box. It is precisely because of this special mechanical structure that Junge encountered this kind of fault.
The fault phenomenon of the faulty vehicle is that the engine noise is too loud in the early stage, the oil pressure alarm light is on in the later stage, the steering wheel is heavy without assistance, and the brake pedal is hard to step on. After the experienced military brother diagnosed, the fault appeared in this accessory box.
The accessory box and camshaft of this engine are driven by the crankshaft through the timing belt at the same time. The main shaft of the accessory box directly drives the high-pressure oil pump and the driving gear of the oil pump. The driving gear of the oil pump is connected with the main shaft of the accessory box through interference fit. The driven gear of the oil pump is driven by the driving gear, which drives the power steering pump and the brake vacuum pump.
Severely worn and cracked accessory case driving gear ofengine oil
The main shaft of the accessory box and the driving gear of the engine oil pump have changed from interference fit to clearance fit
Timing belt with damaged jumping teeth of engine oil
After the disassembly of the accessory case, it is consistent with the preliminary analysis of the cause of the fault of engine oil. The driving gear of the accessory case / engine oil pump is seriously worn and finally cracked, and the oil pump is stuck, but the main shaft of the accessory case still rotates, and the directly driven high-pressure oil pump can still operate, so the engine did not suddenly shut down; The main shaft and driving gear with interference fit slip, and the power steering pump and vacuum pump lose drive, resulting in heavy steering and heavy brake pedal.
Fortunately, when the engine oil pressure alarm is found on the faulty vehicle, th engine engine oil will shut down in time to avoid further and more serious losses. If you continue to drive, there will be serious mechanical accidents such as burning of the main shaft of the accessory box, gear jumping / broken top valve of the timing belt, tension / locking of the main bearing bush and so on.
Here we remind card users who use Iveco SOFIM engine that if the mechanical noise of the engine oil increases and the oil pressure is low, attention should be paid. It is very likely that the accessory box / engine oil pump gear is worn and should be repaired in time to avoid more serious mechanical accidents.
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