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What should you do when your truck has an exhaust oil leak?

What do people usually do when their car breaks down on the road?

A. Directly contact a nearby repair shop for help, but you usually get ripped off;

B. Choose to contact a repair shop you know, but the travel costs end up being too high;

Actually, most of the time, situations like this happen simply because the car owner doesn't have a clear judgment. Even when repair staff get a call for assistance, they often have the owner make an initial assessment to make the next repair steps easier. Today, I'm going to share a classic dilemma case with you all.

Transport vehicle in the rescue

● Case Sharing:

A Foton Auman 340 tractor truck, owned by a driver in his forties, has driven 880,000 kilometers. In 2018, while traveling on a desert road near Suhongtu, he went down a 20-kilometer gentle slope. Out of habit, he parked at an empty spot by the roadside to check the truck and found that the engine’s lower exhaust pipe was leaking oil badly.

After opening the hood, he also found serious leakage around the oil fill hole. An hour after parking, when he pulled out the dipstick, he discovered that the oil level was severely low!

The exhaust pipe under the engine is dripping a lot of oil

● The phenomenon of engine oil dripping from the lower exhaust is mainly caused by two types of faults:

A: 'Oil rising upwards' — damage to the four major components, caused by oil leaking between the cylinder wall and piston after a fault. It’s recommended to stop driving and repair on the spot; otherwise, it could lead to a breakdown on the highway with serious consequences.

B: 'Oil leaking downwards' — caused by excessive wear clearance between the valve stem and valve guide, can continue driving.

At that moment, there were two options:

1. If it’s the four major components, the only choice is to repair right there in this remote place, facing high repair costs and a few days of being “ripped off” during the repair process.

2. If it’s the valve guide damaged, you can continue driving until you get home to fix the valve guide. The repair cost is reasonable and it won’t delay your trip.

At that point, you have to use the process of elimination to determine the cause rationally and scientifically. Considering the engine’s current coolant temperature and oil pressure are normal, idle is stable, the newly replaced four major components have only run 160,000 km, abnormal noise is minimal, no smoke from the rear exhaust, and power is normal, it was concluded that it was oil leaking downwards, most likely due to valve guide damage.

Add engine oil

There's a tiny detail that seems trivial, but in this 'process of elimination' analysis, if you don’t use the exhaust brake and don’t drip oil, it means the conduit is damaged; if you don’t use the exhaust brake but still drip oil, it means the four sets are damaged.

● Starting to pinpoint the problem

To further pinpoint the fault source, we added a small 4-liter bucket of oil and fixed the empty bucket at the lower exhaust pipe connection, then continued driving to investigate.

To avoid the habit of using the exhaust brake, a glove was slipped over the handle switch to prevent messing up out of habit.

Avoid using the exhaust brake habitually.

After nervously driving hundreds of kilometers without using the exhaust brake, I noticed that the lower exhaust was no longer dripping oil and the engine didn’t get any worse, so it could be diagnosed as worn valve guides.

Once I felt comfortable driving 1,000 kilometers, I went to the Shaanxi Auto Weichai service station in Hami, Xinjiang for a quick and proper repair. They replaced all the valves and guides (oil seals). The repair was obviously a bit pricey, but the engine was in good shape, the slight noise disappeared, and the power came back.

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Summer Truck Maintenance Tips to Make Driving Safer!

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