If a rod bearing has failed, you are going to need a new engine. Thic type of failure results in damage to the crankshaft, and the usual cause of the failed bearing is a lack of oil supply to the bearing journal (usually due to restricted oil flow or low pressure due to wear elsewhere in the engine). If you just put a new bearing in to replace the failed one, it is going to happen again very quickly (there is absolutely no doubt about this).
A replacement engine, installed, usually runs in the $3000 to $4000 range, depending on the quality of the replacement engine, prevailing labor rates in your area, and the type of warranty on the job.
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