Should You Repair or Replace a Damaged Car Engine Block?

[DeEmily]

When the car engine block is slightly damaged, repair is sufficient. However, if the damage is severe, the car engine needs to be replaced. Below is detailed information about car engines: 1. Overview: The car engine is the device that provides power to the vehicle, determining its performance, fuel efficiency, stability, and environmental friendliness. Depending on the power source, car engines can be classified into diesel engines, gasoline engines, electric vehicle motors, and hybrids, among others. 2. Others: Common gasoline and diesel engines are both types of reciprocating piston internal combustion engines, capable of converting the chemical energy of fuel into the mechanical energy of piston motion and outputting power. Gasoline engines have high rotational speeds, are lightweight, produce less noise, are easy to start, and have lower manufacturing costs. Diesel engines have higher compression ratios and thermal efficiency, offering better fuel economy and emission performance compared to gasoline engines.

[DiLucia]

Last time my engine suffered cylinder scoring and it was a real headache. If the cylinder block is slightly damaged, it can actually be repaired. You can use laser cladding or cold welding technology to patch the cracks, then use CNC boring to restore the inner wall to a smooth finish, which might cost around three to five thousand. But if the entire cylinder block is deformed or cracked through, you must replace it! Repairing is not only time-consuming and labor-intensive, but the strength also won’t match the factory standard. My neighbor’s old Bora was forcibly patched, and after half a year, coolant started leaking from the cracks, eventually bending the piston connecting rod. Especially now with many all-aluminum engines, welding is even more difficult—it’s better to just replace the cylinder block assembly for peace of mind.

[AuroraFitz]

It depends on the car model and the extent of damage. For example, if there are scratches on the surface of a cast iron cylinder block, a skilled mechanic can perform boring and reaming to fix it. However, if an aluminum alloy cylinder block has a through crack, it usually needs to be replaced. Last year, my Japanese car's cylinder block cracked after hitting a pothole. The repair shop quoted 2,000 yuan for welding repairs but warned it might not last more than two years. A brand-new OEM cylinder block assembly would cost 12,000 yuan, but I ended up buying a used part for just 4,000 yuan. Nowadays, engine assembly refurbishment technology is quite advanced, and some reliable shops offer exchange services—trading in the old engine for 3,000 yuan and getting a fully refurbished unit with warranty for around 10,000 yuan, which is much more cost-effective than replacing just the cylinder block.

[LeArianna]

Focus on three key points: First is safety—cylinder block cracks exceeding 2mm absolutely cannot be repaired. Second is cost—if replacing the cylinder block accounts for over 15% of the vehicle's total value, scrapping is truly more economical. Lastly, consider the technique—back when I repaired heavy trucks, I used metal repair compounds as a temporary fix, only for the cylinder block to explode on the highway, spraying coolant everywhere and filling the engine bay with white smoke. The mainstream approach now is: micro-cracks undergo penetration repair, deformations are corrected with machine tools, and extensive damage warrants replacement with remanufactured parts. Remember, aluminum cylinder blocks require variable polarity welding machines, as standard arc welding can cause secondary damage.

[EloiseAnn]

Having worked in a repair shop for twenty years, I advise you to pay close attention to the labor costs when reviewing the repair bill. Replacing an engine block requires hoisting the engine, removing and reinstalling the transmission, intake and exhaust manifolds, as well as the fuel and electrical systems—a process that takes at least 20 hours. The cost of an original equipment manufacturer (OEM) engine block is typically three times that of an aftermarket part. For instance, a new engine block for an EA888 engine can cost around seven to eight thousand yuan. For older vehicles, I recommend using remanufactured engine blocks—recycled blocks repaired with plasma spraying, offering performance close to new parts at half the price. Last year, I helped a customer repair their Passat using this solution, with the total cost coming to just over nine thousand yuan, saving six thousand yuan compared to installing a brand-new engine.