Is a Flooded Engine After Overhaul the Same as a New Engine?
3 Answers
An engine after being overhauled due to water ingress is not the same as a new engine; it is a repaired component and its value will decrease. Introduction to Engines: An engine is the device that provides power to a vehicle, serving as the heart of the car, determining its power, fuel efficiency, stability, and environmental friendliness. Depending on the power source, automotive engines can be categorized into diesel engines, gasoline engines, electric vehicle motors, and hybrids, among others. Engine Working Principle: A four-stroke gasoline engine mixes air and gasoline in a certain proportion to form a good combustible mixture, which is drawn into the cylinder during the intake stroke. The mixture is compressed, ignited, and burned to generate thermal energy. The high-temperature and high-pressure gas acts on the top of the piston, driving the piston to perform reciprocating linear motion, thereby outputting mechanical energy through the connecting rod and crankshaft flywheel mechanism. A four-stroke gasoline engine completes a working cycle during the intake stroke, compression stroke, power stroke, and exhaust stroke.
There is indeed a difference between a major overhaul after engine water ingress and a brand-new engine. I've seen many similar cases where even after complete disassembly and cleaning of a water-submerged engine, invisible damage remains on metal components inside the cylinder block. Water corrosion affects piston rings and crankshafts - while seals and connecting rods get replaced during overhaul, microscopic scratches inside the crankcase persist. It's like a repaired dropped phone that tends to reboot unexpectedly. Based on my experience, overhauled engines typically show about 5% higher fuel consumption than new ones, with more noticeable vibrations at high RPMs. The biggest headache comes from electrical systems - water-submerged engine wiring harnesses often develop oxidized connectors, triggering random warning lights during operation. Unless working with extremely tight budgets, directly replacing with a new engine proves more reliable.
To be honest, a rebuilt engine is no match for a new one. Last year, my neighbor's off-roader stalled after wading through water, costing over 20,000 yuan to repair the engine. Just six months after getting it back, there was this persistent metal grinding noise during cold starts. The shop diagnosed it as uneven wear on the connecting rod bearings, likely due to an undetected crankshaft deformation from the water damage. Now, whenever he steps hard on the gas, the entire steering wheel shakes. New engines undergo dynamic balance testing before leaving the factory, whereas rebuilt ones with mixed parts have far worse precision. Even the sealant application between cylinder blocks—factory robotic arms apply it much more evenly than manual work. So don't buy into that 'rebuilt like new' nonsense; the performance gap is huge.
