High mileage is not always an indication that an overhaul is necessary, just as low mileage is not always an indication that an overhaul can be avoided. Frequency of maintenance is probably the most important factor. An engine that has its oil and filter changed regularly, as well as regular maintenance, will likely provide many thousands of miles of trouble-free driving. On the contrary, an engine that does not receive maintenance will require rebuilding very quickly.
Excessive oil consumption is an indication that the piston rings, valve seals and/or valve guides need attention. Make sure the seals are in good condition before deciding that the rings and/or guides are in poor condition. Perform a compression test on the cylinders to determine the amount of work required.
Remove the oil pressure sensor and check the oil pressure with a measuring instrument inserted in its place. Compare results with specifications. If the pressure is extremely low, the bearings or oil pump are probably badly worn.
Lack of power, rough running, knocking or metallic sounds from the engine, loud valve noise and excessive fuel consumption may also indicate the need for an engine overhaul, especially if they are present at the same time. If a complete setup and adjustment does not improve the situation, then the only way to solve the problem is to overhaul the engine.
Engine repair involves bringing the internal engine parts to a new condition. During repairs, piston rings are replaced and cylinder bores are ground. When performing cylinder surface treatment in a specialized auto repair shop, it will be necessary to install larger pistons. The main and connecting rod bearings are usually replaced with new ones, and if necessary, the crankshaft can be ground to restore the journals. Usually, it is necessary to resort to repairing the valves, since their condition usually leaves much to be desired. When rebuilding an engine, external components such as the starter or alternator can also be rebuilt. In the end, the engine should be as good as new, providing many kilometers of mileage without problems
Caution: Cooling system components such as hoses, drive belts, thermostat and water pump must be replaced when performing major engine repairs. You should carefully check the radiator to make sure it is not clogged or leaking. We also recommend overhauling the oil pump.
Before you begin rebuilding your engine, please read the entire process description carefully to familiarize yourself with the skills required to perform the job. Rebuilding an engine may not be that difficult if you follow all the instructions carefully, use the necessary tools and strictly observe the control dimensions; however, this may take quite a long time. Plan to keep your vehicle out of service for at least two weeks, especially if you need to have certain parts repaired at a specialist workshop. Check that you have the necessary spare parts and make sure that you have all the necessary tools and equipment ready in advance. Most of the work can be done using common, everyday tools, but special precision measuring tools are also required to determine whether certain parts need to be replaced. Often, a specialist workshop can take the necessary measurements and also advise on the need for replacement and/or repair.
Caution: Always wait until the engine is completely disassembled and all components (especially the engine block) will be checked. before deciding which actions need to be delegated to a specialized workshop. Since the condition of the block is the main factor in deciding whether to rebuild the old piston group or purchase a new one, never purchase parts or machine parts until the cylinders of the block have been thoroughly inspected.
In conclusion, it must be said that in order to ensure maximum service life and a minimum number of problems on the engine after repair, it is necessary to carry out assembly very carefully and in conditions of complete cleanliness.