How To Tell Your Medium-Duty Engine Block Is Cracked?

In you mid-size import truck, the engine's cooling system is a closed system, so the coolant circulates from the engine's cooling passages to the radiator, the heater core and back again. It should never leave that loop. If it's somehow getting into the oil passages or the cylinders (and, from there, out the tailpipe) something has gone terribly wrong. Your head gasket has cracked, your head itself has cracked or, worst of all, your block has cracked.

You can crack an engine block several ways, but there are some that are more common than others:
- Running water through the cooling system instead of antifreeze in cold weather
- Running cold water through an already hot engine

Related: Causes of a Cracked Engine Block

A cracked engine block can cause performance troubles with any Mitsubishi Fuso FE, FH, FK or  Isuzu NPR, NQR, any other mid size truck, and in time, can cause your vehicle to stop running altogether. Fortunately, there are ways to identify a crack in the engine block, which can help lead to repairs or replacements.

1. Look for leaking engine coolant, most notably as it drains out the bottom of a car. This is a telltale sign of a cracked engine block, and in time, can cause an engine to overheat.
2. Check the dashboard and check gauges. If any of the dashboard lights come on, whether related to oil or coolant, this could signify a cracked engine block. Also, if the temperature gauge begins to signal overheating, this could mean engine coolant is leaking, which is a potential sign of a cracked engine block.
3. Look for extra smoke coming out of an automobile's exhaust pipe. While a certain amount is common, extra amounts--long trails coming out of an exhaust pipe--could signify a cracked engine block.
4. Check to see if a car radiator's mixture of engine coolant and water is optimal. This should be half water, half antifreeze, in most cases (it will often be indicated on an antifreeze bottle's instructions). If the mixture is not proper, this can cause the mixture to freeze, which will crack the engine block.

There are very few engine failures that any mechanic would consider beyond repair, but first among them is the cracked engine block. The end result is generally irreparable damage. Additives like sodium silicate (a.k.a. "liquid glass") can help delay complete failure of a slightly fractured block, but it will never be as strong or reliable as it once was.

Engine Block Cracked?

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If you or a co-worker needs replacement parts for your medium or heavy duty commercial truck, call us at (803) 564-3228 or (877) 564-6307. If you have any difficulties getting through our phone system, please use our Contact Form or Parts Request Form, or email sales@busbeetruckparts.com.
We have hundreds of Salvaged Medium Duty Trucks and Commercial Box Trucks for Parts including: Isuzu, Mitsubishi Fuso, UD, and GMC. With thousands of parts, including our most popular Isuzu NPR Truck Parts, we should have any part that you need in stock. Our sales professionals will be glad to assist you.  We are located at 4107 Festival Trail Rd, Wagener, SC 29164.

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Causes of a Cracked Engine Block in a Medium Duty Truck

A cracked engine block in your Isuzu, Mitsubishi Fuso, Hino or UD box truck, believe it or not, is one engine failure that a mechanic would consider beyond repair. While it remains fairly rare, the end result tends to be irreparable damage. Additives like sodium silicate (a.k.a. "liquid glass") can help delay complete failure of a slightly fractured block, but it will never be as strong or reliable as it once was.
    
Overheating
Overheating is, by far, the most common cause of cracked blocks. Engines blocks are cast with many small channels, sharp edges and tight clearances. Coolant can only cool what it touches, so extreme overheating causes localized temperature spikes in the engine block. The metal in those places will try to expand away from the cooler areas, causing the engine block to literally rip itself apart from the inside.

Related:  Engine Overheats: Troubleshooting

Rapid Cooling
Rapidly cooling hot metal with cold water will cause those metal directly in contact with the water to contract faster than the metal beneath. The metal develops microscopic fractures that quickly propagate into large cracks. Pouring cold water into a dry and overheated cooling system can cause another type of localized heat-related cracking when the portions of the block directly in contact with the water contract away from the hotter portions.
     
Core Shift
"Core shift" is a manufacturing defect. Engine blocks are "investment-cast" by injecting liquid metal into molds made of highly compressed sand. The sand can shift slightly during the casting process, leaving the block thinner in some places than in others. Such core shift is fairly uncommon on newer engines, but poses a serious and un-fixable threat to older castings.

Related: Don't Trust the Jug - Prevent Engine Failure

Overpowering
Overpowering engine blocks to the point of destruction was once fairly rare, but the explosion in popularity of aftermarket turbocharging/supercharging (a.k.a. "forced induction") and nitrous oxide (N2O) injection makes this a very real possibility for enthusiasts looking for more power. Before these technologies came to dominate the marketplace, engine horsepower was generally limited by the connecting rod's ability to withstand breaking at high RPM. Forced induction and nitrous work by increasing power throughout the engine's entire RPM range, making engine block strength the limiting factor. Stress-related cracking usually occurs in the area surrounding the engine's main crankshaft caps, known as the "webs." The webs act as a mounting point for the main caps, which secure the crankshaft to the block and bear most of the abuse.

Related: How Can I Tell If an Engine Block Is Cracked?

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If you or a co-worker needs replacement brakes or brake parts (booster, cable, calipers, rotor, etc.)  for your medium or heavy duty commercial truck, call us at (803) 564-3228 or (877) 564-6307. If you have any difficulties getting through our phone system, please use our Contact Form or Parts Request Form, or email sales@busbeetruckparts.com.
We have hundreds of Salvaged Medium Duty Trucks and Commercial Box Trucks for Parts including: Isuzu, Mitsubishi Fuso, UD, and GMC. With thousands of parts, including our most popular Isuzu NPR Truck Parts, we should have any part that you need in stock. Our sales professionals will be glad to assist you.  We are located at 4107 Festival Trail Rd, Wagener, SC 29164.

Be sure to Subscribe to the Busbee Blog for more helpful tips and tricks for safe and easy driving. Follow us on Facebook and Twitter, and sign up for our Free Monthly Newsletters.