When an engine has driven for tens of thousands of miles, those drives can naturally wear on the engine bearings and deform piston rings so that they don’t properly seal. You may notice that your engine burns through oil, or is tough to start and low on power when it does. All of these can be symptoms of an engine that needs overhauling.
Below, we’ll outline when to know it’s time for an overhaul, and how you can overhaul your engine.
What is an Engine Overhaul?
An engine overhaul is the replacement of most of the components of the engine aside from the core engine block. You can replace all of these components, or just the ones you think need replacing. With an overhaul, you’ll save money compared to replacing the entire engine while getting many of the same benefits — ideally, things like improved power, better oil economy and no excessive oil clearances.
An engine should usually be overhauled in case of low or no engine compression, excessive oil consumption or excessive bearing clearances.
If you have issues with your suspension, brakes or transmission, overhauling your engine won’t fix these problems. But if you know that your engine is burning through oil or having trouble starting, then an engine overhaul can be your best bet.
Overhauling Your Engine
To overhaul your engine, you’ll start by draining the engine of fluids. Then, you’ll either remove the engine with a hoist or remove it and transfer it to an engine stand so that you can have access to the engine from all angles.
Next, you will carefully remove the parts that you’ll need to replace — and, as necessary, any part that’s in the way. Unless you’re just replacing one or two easily accessible parts, you’ll probably be taking apart the entire engine.
Once you’ve deconstructed your engine, organize the old parts and start rebuilding the engine with your new parts — you can either buy these parts individually, or purchase al kit that comes with everything you need for an overhaul. This can be a bit of an involved process, and you’ll be keeping track of 10 or more different engine components. Organizing your work-space before you start the overhaul can help you ensure that you don’t lose track of any bearings or pins.
You should also budget a decent amount of time to overhaul your engine. Pick a day or weekend where you don’t have anywhere to be, or when you can count on another car in case of an emergency.
Once an engine is overhauled, you’ll need to break it in. This will prep the engine with some pressure and new oil, and encourage the new piston rings to properly fit themselves to the cylinder walls. You can break in an overhauled engine the same way you would break in a new engine. Don’t push the engine to the redline, don’t floor it, avoid shorter trips and try not to use synthetic oils.
How many miles you’ll need to break one in will vary from engine to engine — manufacturers recommend anywhere between 300 and 1,000 miles. Once you’ve hit around 500 miles or so on the overhauled engine, you should be good to go in most cases — and can drive at whatever speed and use whatever kind of oil your heart desires.
This step may seem optional, but not following it can seriously reduce the lifespan of your over hauled engine.
Saving an Engine With an Overhaul
An overhaul won’t fix any other problems with your car, but it is one of the best ways to repair an engine that has low or no compression or is burning through oil.
Overhauling an engine can be a bit of an involved process, just because of the number of engine components you’ll need to keep track of and replace. When overhauling an engine, budget more time than you think you’ll need and organize your work-space beforehand. The overhaul process can take a lot of labor, but it’s almost always cheaper than buying or building a brand new engine.