Is A Rebuilt Engine As Good As New?

By Chris Thatcher

Updated Feb 18, 2024

In Learn Feb, 2024

Tired of that check engine light coming on all of the time? Is an engine rebuild worth it or are new engines better?

Table of Contents

    In many cases, rebuilt engines are just as good, or better, than buying one fresh from the manufacturer.

    Is A Rebuilt Engine As Good As New

    Several factors go into whether or not brand new or rebuilt engines are going to be right for you. Most people prefer a properly rebuilt engine to a brand new one. It mainly comes down to who rebuilt the engine and whether or not they knew what they were doing.

    Should You Do An Engine Rebuild?

    Whether or not an engine rebuild is the right choice for your vehicle depends on a few things.

    The biggest thing to consider is who would be doing the work. Do you have any experience rebuilding engines? If you choose to buy a brand new engine, you’re not likely to run into many defects from the manufacturer, but not everyone likes the original equipment performance standards and internal components of an original.

    With a rebuilt engine, you can make sure you get something that’s going to work for your personal preferences and needs. Rebuilt engines can be built to your specifications.

    The task of completely deconstructing and rebuilding an engine is not an easy one, and it’s completely understandable if it’s not something you want to tackle on your own.

    The good news is, there are plenty of mechanics that are experienced in engine rebuild as well as engine repair or overhauling that would be able to rebuild your engine for you.

    Overhauling VS. Rebuilding

    The terms engine rebuild and overhaul are often used interchangeably when talking about repairing or upgrading an engine.

    Truthfully, both terms are correct. A rebuild or overhaul covers anything from replacing parts that are worn and in need of replacement, all the way to completely tearing down and rebuilding the engine.

    Overhaul Kits

    For those that have the skills to tackle the overhaul on their own, they can purchase an overhaul kit, which many manufacturers offer. These kits are ideal for when you’re swapping out worn-out parts of your engine. Some of the common things that are come in an overhaul kit include:

    • Connecting rod
    • Cylinder head hardware  
    • EGR valve
    • Gaskets
    • Oil-pressure regulator  
    • Pins   
    • Pistons 
    • Rings  
    • Skirts  
    • Thermostats   
    • Valve-train components

    How Long Will A Rebuilt Engine Last?

    This can be a more complicated question than many people think. The conditions that you put the engine through both before and after a rebuild, as well as how the rebuild is done, will have an incredibly large effect on how the rebuilt engine lasts.

    Assuming the engine was not mistreated or abused in the period before the rebuild became necessary, the rebuild can be looked at as a refresher for the engine and can give the engine a minimum of another 100,000 miles.

    While this may not seem like much if you put 500,000 on it before the rebuild, but considering rebuilding the engine can keep it out of the junkyard for another 20% of its lifespan, that is a pretty solid return.

    This also assumes that the owner is going to treat the engine well after the rebuild as well. Doing a rebuild on an engine in its golden years doesn’t mean you can take it out and drive it like you stole it, it simply extends the normal useful life of the engine. You should still perform regular maintenance and oil changes just as you would with a new engine to get the most benefit from it.

    Additionally, the quality of the technician that does the rebuild is a major factor in not just how long the engine will last beyond the rebuild, but how well it will function in the meantime. Good mechanics will have a much higher quality engine build than a lower quality tech, and using sub-par labor can shorten the life of any engine, rebuilt or not.

    Is It Better To Buy A New Engine Or Rebuild

    There are very few situations where a new engine will be a better choice than a rebuilt engine. In most situations, a rebuilt engine will not only perform better but will be far cheaper than a new engine. One of the times when a rebuild may not be ideal is if there was some sort of catastrophic engine failure that leads to engine block damage.

    The engine block is the core of the engine and it houses some of the most important engine components. In some situations where the block is damaged, such as when it freezes and cracks a water or coolant journal, or if there is block damage from a timing failure in an interference engine. In cases like this, the damage to the metal of the block may be too severe to replace with welding or other fixes and the block is no longer usable.

    Another situation where a rebuild may not even be possible is for a seized engine. Seizing happens when the engine is running hot but runs out of oil, or the oil is too low to properly lubricate the pistons, crank, and other important mechanical components of the engine. This leads the engine to essentially weld itself into an immovable chunk of iron and steel, and even with full disassembly a seized engine usually cannot be saved.

    In cases like these, since the engine block is one of the most expensive and difficult to repair core components, a new engine will often be cheaper to obtain and install.

    The Consensus On Rebuilt Engines?

    Yes, in nearly any common situation and provided the engine rebuild is done by someone with skill and experience, a rebuilt engine is as good as, or even better than, a new one. Having an existing engine rebuilt won't be much different overall than extensive engine repair.

    Your technician will commonly use much better parts than what came in the engine originally, leading you to have better equipment overall than what your vehicle had in the first place.