Fix Or Replace?

Sept. 28, 2010

As the life before overhaul of many heavy-duty diesel truck engines continues to extend, the question of whether to choose an overhaul of the truck's existing engine or replace it with a remanufactured engine, or neither, is no longer a simple matter of minimizing the immediate direct cost.

As the life before overhaul of many heavy-duty diesel truck engines continues to extend, the question of whether to choose an overhaul of the truck's existing engine or replace it with a remanufactured engine, or neither, is no longer a simple matter of minimizing the immediate direct cost.

Trade It In?

Depending on the severity of a construction fleet's operations, nowadays it may be practical to take a page from the over-the-road side of trucking and trade the entire truck before it hits the mileage of its first scheduled overhaul.

In moderate-mileage operations where maintaining the company's image requires keeping the trucks looking fresh, a trade-in cycle timed to around 80 percent of the engine's projected life before overhaul might be the best way to completely avoid the question of choosing between overhauled or remanufactured. This is especially true when the "business end" of the truck (body, equipment, etc., added to the chassis) is easily installed, replaced or transferred between trucks.

... Or Not

However, at the opposite ends of the scale, very high mileage and very low mileage, trading within the first overhaul period is generally not practical or cost-effective.

High Miles - Low Wear

Some trucks, typically those dedicated to regional material hauling, rack up lots of miles without putting much wear and tear on the truck chassis or body. In this case, the effective life of the truck chassis might encompass multiple engine overhaul periods.

High Hours - Low Miles

Another common situation in construction operations involves trucks that don't accumulate very many miles, but due to the operation of PTO-powered equipment, these trucks rack up engine hours on a wholesale basis, making it to their first scheduled overhaul while the rest of the truck is just starting to get broken in. As a side note, this is why it is important to keep track of BOTH miles and engine hours in your maintenance records.

High Complexity

Less frequent, but still common in construction operations, are trucks where there's a high level of integration between the body/equipment and the truck chassis, such as a concrete pumper, that makes it difficult, if not impossible, to cost-effectively move the body/equipment to a new chassis. In these instances, multiple engine overhauls/replacements — and even cab replacements — might take place before the body/equipment reaches the end of its useful life.

High Damage

Finally, the other occasion in which the question to overhaul, replace or trade in occurs when there has been a catastrophic engine failure requiring major repairs to the engine. In this situation, an "in-frame" overhaul isn't an option, as complete disassembly is required to ensure the integrity of the repair, so the remaining choices are an out-of-frame shop overhaul, replacing with remanufactured, or trading in the truck.

Which Way To Go?

Assuming that trading in the truck isn't a practical consideration, and assuming that any engine damage hasn't reached the point of seeing daylight straight through the block, the question of whether to go with an overhaul of the engine or to replace it with a remanufactured engine still remains.

In-Frame Overhaul

If the engine has reached its first scheduled overhaul without any serious damage or undue wear, and if downtime isn't ultra-critical, then an in-frame (engine block and crankshaft stay in truck) overhaul is usually practical.

According to Navistar Service Parts Product Support Team Manager Steve Sawyer, this type of overhaul typically involves replacement of the rod and main bearings, rods, pistons and rings, cylinder liners, and remanufactured cylinder head(s). An in-frame overhaul generally does not include any work on the cam and cam bearings, the drive gears or timing gears, or any machining to the block or crankshaft.

Sawyer emphasizes that if there has been any significant damage to the internal engine parts, an in-frame overhaul is precluded because the engine must be fully disassembled, cleaned and inspected to ensure the integrity of the repair.

Out-Of-Frame (Shop) Overhaul

By the time an engine has reached its second scheduled overhaul, the necessity to replace cam bearings, timing/drive gears and other parts requires the engine's removal from the truck chassis. As previously mentioned, getting the engine out of the truck is also necessary if there has been a catastrophic failure of any internal engine parts.

Once the engine is out of the truck, the overhaul can be accomplished in the fleet's own shop, at the truck/engine dealership, or at a machine shop specializing in engine overhauls. Most fleets don't have the facilities and equipment needed to properly perform an overhaul, so this task is generally jobbed out. Even larger fleets with extensive shop resources still need to consider whether a mechanic's time is better spent on routine day-to-day repairs or dedicated to overhauling an engine.

In some smaller markets, even the truck dealer may lack the appropriate resources, so an engine requiring overhaul might be sent out to a regional facility.

Given the distance an engine may have to go to be overhauled, and the total time involved, the truck's downtime must be directly factored in to the cost when deciding between overhauled and remanufactured. If there are extra unused trucks in the fleet, or if the fleet already has a spare engine sitting on the shelf, then the downtime isn't much of a worry.

On the other hand, in a smaller operation where every truck must be available for work every day, downtime is a much bigger factor. When losing $500–1,000 per day from lost work, it doesn't take long before any cost savings from choosing a less-expensive option are quickly offset by lost revenue.

Replacing With A Remanufactured Engine

If damage to the engine block is severe, or if an out-of-frame overhaul isn't practical because of downtime concerns, then the best option is to go with a factory remanufactured engine to replace the truck's existing power plant.

There are even some instances where an in-frame or out-of-frame overhaul may be practical, yet replacing the engine with a remanufactured unit may still be preferable.

Because remanufactured engines typically have longer and more extensive warranties than an overhauled engine, smaller operations that are ill-equipped to deal with the cost of unplanned repairs might choose the remanufactured option for the security of its warranty coverage. As an example, Sawyer cites International's two-year, unlimited mileage warranty on its "ReNEWed" brand of factory remanufactured engines, compared to a one-year warranty on overhaul parts.

Also, when fleets sell or trade their older trucks, they'll typically find that having a remanufactured engine in the truck, even with half of its overhaul life already used, will bring a higher resale value, offsetting the initial cost premium of the remanufactured unit. When the remanufactured engine warranty is transferable, that brings even more value to the resale picture.

Because installing a remanufactured engine can take less than half the time of the best-case overhaul scenario, operators with high downtime costs may find the remanufactured engine cost premium to be less significant, when all cost factors are considered. Combine that with the warranty and resale value and the cost premium can all but disappear.

Not Just Time And Money

Unlike an overhauled engine, a factory remanufactured engine can benefit from the latest processes and technology that an engine manufacturer can bring to bear.

Because every part in a factory remanufactured engine is checked and/or upgraded to meet the manufacturer's latest specifications, it can literally be "better than new" compared to the original engine when the truck rolled off the assembly line.

According to Sawyer, "the camshafts in our new (EPA 07 spec) engine had to be made more robust to withstand higher loads, and that improvement has now been incorporated all the way back into International's legend product camshafts to deliver that advantage across the (remanufactured) engine line."

The latest factory machining processes, many of which are beyond the reach of most overhaul shops, are typically employed to make the remanufactured engine as durable, reliable and efficient as the newest engines built today.

According to International Truck & Engine's vice president of product management, Ron Sandefur, "International's ReNEWed engines offer the latest improvements in performance, fuel efficiency and environmental benefits. It's very difficult for anyone to go back and make a retrofitted engine. Each year, engines come out with more torque, horsepower and produce fewer emissions, and it's incredibly complex to match the electronic components from a specific model year with parts available today."

No Easy Answer

While there may be quite a bit in favor of choosing remanufactured instead of an overhaul, the cost premium is still significant. When time is not a critical factor, choosing to overhaul can save as much as half the cost of a remanufactured engine. According to Navistar's Steve Sawyer, overhauls still outsell remanufactured engines at a rate of 5-to-1.

If a fleet operates at the extreme ends of the size/mileage/wear spectrum, one of the engine repair options will likely emerge as a clear choice.

For the majority of contractors whose operations lie between the extremes, there is no single all-purpose answer. Given similar circumstances, one truck may get an in-frame overhaul, another will get an out-of-frame overhaul, another will get a remanufactured engine, and yet another will be traded in.

These days, choosing the right option for a particular truck requires not only the input of the fleet's shop manager from the mechanical perspective, but also the accountant to consider cost/tax implications, the operations manager to consider fleet demand/readiness, and even the local truck dealer's sales personnel to provide input on the current resale market.


'6 Tips For Summer Cool

While all of Komatsu's articulated haul trucks are designed to operate year 'round without any major changes, here are some maintenance and application tips that can help all trucks run better in the summer.

  • Get plenty of fluids. When the mercury in the thermometer rises, fuels, coolants and lubricants need to be changed according to the ambient temperature. Before the summer really heats up, be sure to check out the details for your truck in the operation and maintenance manual.
  • The right tire pressure means the right tire traction. Applications change with warmer weather and with that change, ground conditions can alter drastically. Tires should be inflated to the correct pressure for maximum traction under poor conditions, so make sure that tire air pressure is on your daily maintenance check list.
  • Keep it clean. In the hotter and dustier environment of the summer months, air cleaners for the engine and air conditioner should be replaced more frequently for maximum engine performance and operator comfort.
  • Extra traction may require extra training. Typically in summer months there is an increased need for greater traction. This is probably one of the most important things to prepare for because it is essential that the operator is familiar with the power train controls so that s/he can lock up the axles and differentials as required for maximum traction. A key thing to remember is that additional operator training may be required to achieve optimal truck performance under poor ground conditions that often exist in the summer months.
  • Be smart about your job layout. As ground conditions worsen, an often overlooked but extremely necessary step is to make sure that your job is set up to move the material in the most efficient way. If the shortest route is through the worst ground conditions, it may not be the most efficient or lowest-cost method of moving material.
  • Keep your cool. Your own hydration is also very important for safety and comfort in the summer. So, look for a truck equipped with a cool box to keep your thirst-quenching refreshments nice and cool during the dog days of summer.