There are many reasons that indicate you to go for an engine replacement, or an engine reconditioning. Sometimes engine repair is required at the earliest to save the engine, otherwise the engine will be ceased and then only replacement will be the solution. If you go for engine repair at the right time, there may be the chance of expensive treatments for your vehicle which may suffer you a lot.
The first sign that indicates you an engine replacement is blue smoke from the tailpipe on the time of start-up or when accelerating after coasting. The blue smoke comes out when the oil leaking past worn cylinder bores and piston rings or through worn valve guides and into the combustion chamber where it is burnt along with the mixture of air and fuel.
More seriously, when you hear different noises from your car’s engine. An engine needs to be replaced when unusual sounds from within the engine block that increase with crankshaft speed rather than road speed. Most engines feature a crankshaft with plain journal main and road bearing.
Moreover when you hear knocking sound, make it sure that the connecting rod bearings are worn and in the process of failing, the noise itself being caused by excessive clearance between the crank journal and the bearing, or most probably the reason that the wrist pin is failing.
When there is too much clearance on the main head bearings, there is a rumbling noise came from the engine block which clearly indicates the engine replacement.
When you find the coolant leaking from anywhere on the engine other than from the freeze plugs or hose connections, this strongly indicates that the cylinder block is cracked. No matter if it is built from the cast iron or from aluminum, it clearly indicates an engine replacement. Sometimes, repairing an engine and its labor cost is far expensive than an engine replacement.
These are the main reasons where you go for engine repair or engine replacement.