The CAT D399 is indeed a heavy-duty engine with 16 cylinders in v-shape. Due to its size, it is mostly used in generators.
Most common problems found in the CAT D399 engines:
1. Bearings issues: One of the most common problems found in the CAT D399 have to do with the crankshaft bearings. It’s not that the bearings are designed poorly, but it is usually one of the weak points in the engine.
It is on this note that you would need to pay attention to the sound of the engine when the engine is running. If you hear any grinding noise, then you would need to stop the engine because it could be the bearings are grinding.
You can also notice this if you pay attention to the oil you drain from the engine. You need to check for bearing particles; if you see them, then you would need to take action immediately.
The way the engine was designed, makes it easy to check the bearings. Loosen the cover on the engine block to get access to the crankshaft journal.
To prevent any issues with these bearings you need to do the following;
- a. Regular scheduled maintenance to prevent oil sludge and replace the oil filters.
- b. Prevent oil starvation as much as possible.
- C. Use the right oil.
- d. Replace the bearings when you overhaul the engine.
2. Low oil pressure: Low oil pressure is another problem encountered on these engines. Sometimes you can experience the oil bar gauge drop gradually as the engine is running.
Such problems can be caused by a faulty oil sensor. The sensor can send the wrong signal.
Other things that can cause low pressure are;
- a. Bad crankshaft bearings: if the crankshaft bearings are bad, it can cause low oil pressure.
- b. Faulty oil pump: The oil pump should be the primary focus when you have low oil pressure. Use a manual gauge to check the oil level to ascertain if the problem is the oil pump.
3. Crankshaft journal problem: As mentioned earlier, the engine is prone to bearing issues. These bearing issues usually affect the crankshaft journal. You should also remember that this is a V-engine, so on each journal, there are two connecting rods, which cause a lot of stress on the crankshaft journal, which leads to crankshaft journal problems.
4. One or two cylinders not working: This is one of the problems that is difficult to detect. When the engine is running, you may not know that not all cylinders are working. Although the piston is traveling inside the cylinder, the phase may not be working.
The major cause of this is fuel-related. The particular cylinder may not be receiving fuel due to a faulty injector. Sometimes, stuck rings could also be why a particular cylinder is not working.
5. Low frequency under load: This problem is applicable when the engine is used as a generator. If you notice low frequency, it has to do with the engine speed, which is controlled by the fuel pump governor.
Therefore you need to check the pump and see why the rpm of the engine has dropped.
6. Clogged oil cooler: The type of oil cooler used in this engine is a tube type. The bath is in the coolant, so if the tube becomes clogged, it could cause issues with the engine, which could also be another reason for having low oil pressure.
7. Oil and coolant dilution: In the CATD399, the type of the oil cooler makes it possible for oil and coolant to mix. If the oil tube starts leaking, the coolant will mix with the oil.
A bad liner seal could also cause the oil and coolant to leak together.
These are some common problems found in the Caterpillar D399 Engine.
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