If you have ever tried to purchase a replacement engine for a vehicle before you may have run into any of the many pitfalls that can happen when trying to select either a reconditioned engine or a second hand engine. This will be a guide to the common problems and hopefully be able to show you how to choose the ideal engine for your vehicle with as few problems as possible.
First thing you should consider when shopping for a replacement engine is what type of engine you would like to purchase. You will normally have the choice of either a second hand engine or a reconditioned engine.
The second hand unit has both positives and negatives associated with it. On the positive side the second hand engines are normally cheaper than reconditioned engines. One of the other positives of second hand engines is that you can sometimes get them in a “complete” state. Which means it will have manifolds, brackets, and other bolt on items already attached to them when they are delivered. The negative aspects of a second hand engine are generally, you do not know the actual mileage of the engine you are buying, you do not know how the original owner drove the vehicle before the engine was taken out of it. This means you could end up installing a replacement engine into your vehicle with parts inside of it that are near the end of their life. Also you may find if the unit is sent to you in a “complete” state,the engine itself will have a warranty on it for however long the supplier is willing to give ( normally 3 months) the ancillaries will not carry this same warranty and many times you are better off taking off the known working ancillaries from your original engine and reinstalling them on the replacement engine. This means more labour as they have to be removed from both engines and reinstalled on the replacement.
The reconditioned engine also has its positive points and negative points. On the negative side a reconditioned engine is generally more expensive than a second hand engine. The reconditioned engine will have a break in period where the vehicle needs to be driven at a milder lower rpm in order for the bearing surfaces and piston rings to bed themselves in over a normal period of 1000 to 1500 miles. Also reconditioned engines normally come in a “bare” state. Which means what you are supplied with is a cylinder head and engine block, sometimes they do come with a rocker cover and a sump attached but since the same bare engine block may fit a range of different vehicles, it is not uncommon to have to change these parts over with your original engine. On the positive side while a reconditioned engine is more expensive the extra cost can be directly attributed to the work that has gone into it in order to provide you with the best unit possible to ensure long life as long as it has proper maintenance. Generally any reconditioned engine has been disassembled, machined, wearable parts inside the engine are replaced for new, mating surfaces for gaskets machined the engines are also cleaned and sometimes painted so there is also less mess involved for your mechanic. Another positive is the fact that a reconditioned engine that has had all the wearable parts inside replaced for new will in effect have 0 miles on it. used auto parts
Some of the common things heard in the trade from different mechanics are all based on personal preference. You may run into one mechanic that tells you that he only likes to fit second hand engines as he perceives getting a bare block to be more work to install. Not taking into account that to do the job properly he should be changing over all the ancillaries anyhow, in which case the reconditioned engine makes this task easier as the ancillaries are already removed before it is sent to you. Then you may run into another mechanic that will only want to install reconditioned engines, they do not trust second hand engines as they cannot guarantee that in 2 months you will not come back to them with another failed engine because the second hand engine was just taken from one vehicle and put into yours.
At the end of the day the decision is up to you, the vehicle owner, what type of engine you choose for your vehicle. If you plan to keep the vehicle for a long period of time, then reconditioned would be the preferred choice. If you plan to just install an engine and then sell the vehicle on or get rid of it then a second may do the job for you.