A long block is most of your engine in one piece, minus the external parts you can see

An engine long block is the core of your engine — the block itself, the cylinder head, the pistons, the crankshaft, the camshaft, and the valves — all assembled together. What it does not include are the parts bolted on the outside: the intake manifold, exhaust manifold, alternator, water pump, air filter housing, and fuel injectors. Think of it as the engine's skeleton and vital organs, but not the accessories hanging off it.

You buy a long block when your current engine is damaged beyond repair but you do not want to replace the whole car. A cracked block, a seized engine, or internal damage that costs more to fix than the engine is worth makes a long block a practical middle ground between an engine rebuild and scrapping the vehicle. The long block arrives ready to bolt into your car — you transfer over the external parts from your old engine, reconnect hoses and wiring, and you have a working engine again.

Long blocks come in three main types: new (built by the manufacturer), remanufactured (taken apart, inspected, worn parts replaced, reassembled to factory specs), and used (pulled from a salvage vehicle, tested, and sold as-is). Each has different costs and different risks, which we cover below.

Key Takeaways

  • A long block includes the engine block, cylinder head, pistons, crankshaft, and camshaft, but not the bolt-on accessories like the alternator or water pump.
  • You need a long block when internal engine damage makes repair uneconomical, but the rest of your car is still worth keeping.
  • New long blocks cost the most but come with a warranty; remanufactured blocks cost less and carry a warranty; used blocks are cheapest but have no may provide.
  • Installing a long block requires transferring your old accessories, draining fluids, and disconnecting engine mounts — a job that typically takes a mechanic eight to twelve hours.
  • The long block must match your car's year, make, model, and engine size, or it will not bolt in and will not run correctly.

New, remanufactured, and used long blocks have different costs and guarantees

A new long block comes directly from the manufacturer and has never been installed in a vehicle. It costs the most — often $2,000 to $5,000 or more depending on the engine — but it arrives with a full manufacturer warranty, usually three years or 36,000 miles. You are buying peace of mind: the engine is may provide to work, and if something fails within the warranty period, the manufacturer replaces it. New long blocks make sense if your car is newer, worth a significant amount, and you plan to keep it for years.

A remanufactured long block has been removed from a vehicle, completely disassembled, inspected for wear, had damaged or worn parts replaced with new ones, and reassembled to the manufacturer's original specifications. It costs less than new — typically $1,200 to $3,500 — and usually comes with a warranty of one to three years, depending on the rebuilder. Remanufactured blocks are a middle path: they are not brand new, but they have been professionally restored and carry a may provide. Many independent machine shops and some dealerships offer remanufactured blocks.

A used long block is pulled from a salvage vehicle, tested to confirm it runs, and sold without any warranty or with a very short one (sometimes 30 days). It is the cheapest option — $500 to $1,500 — but you are taking the risk. The engine may have hidden damage that does not show up when ready, or it may fail shortly after installation. Used blocks work if your car is older, worth less, and you need the lowest upfront cost. Many salvage yards and online marketplaces sell used long blocks, but you have no recourse if the engine fails after you install it.

Your long block must match your car's exact engine specifications

Before you order a long block, you need to know your car's engine size, type, and year. A 2010 Honda Civic with a 1.8-liter four-cylinder engine cannot use a long block from a 2010 Honda Civic with a 2.0-liter engine, even though both are Civics from the same year. The bolt patterns, mounting points, and internal dimensions are different. Installing the wrong long block means it will not fit, or it will fit but the car will not run correctly.

Find your engine specs on the vehicle identification number (VIN) plate, usually on the driver's side dashboard or door jamb. You can also look in your owner's manual or call a dealership with your VIN — they will tell you exactly which long block you need. When you contact a salvage yard or parts supplier, give them your VIN, not just your car's make and model. Many suppliers will cross-reference your VIN automatically and show you only compatible long blocks.

Mileage on a used long block matters less than you might think. An engine with 80,000 miles that was well-maintained may run longer than one with 40,000 miles that was neglected. Ask the salvage yard about the donor vehicle's history if you can, but focus more on whether the engine has been tested and whether it comes with any warranty.

Installation requires transferring your accessories and takes most of a day

Installing a long block is not a job for someone without mechanical experience. The process involves draining all fluids from the old engine, disconnecting the battery, removing hoses and wiring harnesses, unbolting the engine mounts, lifting the old engine out with a hoist, and then reversing the steps with the new long block. A professional mechanic typically charges eight to twelve hours of labor, which translates to $800 to $1,500 or more depending on your location and the shop's rate.

Before the new engine goes in, you transfer the accessories from your old engine: the intake manifold, exhaust manifold, alternator, water pump, thermostat housing, fuel injectors, ignition coils, and any other bolt-on parts. Some shops include this transfer in their labor estimate; others charge extra. Ask upfront whether the quote includes removing and reinstalling your accessories or if that is separate.

After the long block is installed and bolted down, the mechanic refills all fluids (oil, coolant, transmission fluid), reconnects the battery, and starts the engine to check for leaks and listen for unusual noises. The first start is critical — if something is wrong, you want to catch it before you drive the car. Most shops will run the engine for a few minutes and let it idle to make sure everything is working.

Warranty coverage varies widely and affects your long-term risk

New long blocks from manufacturers typically come with a three-year, 36,000-mile warranty that covers defects in materials and workmanship. If the engine fails within that window, the manufacturer replaces it. Some dealerships extend this to five years or 60,000 miles if you buy the long block through them.

Remanufactured long blocks usually carry a one-year, 12,000-mile warranty from the rebuilder. Some offer longer coverage — up to three years — but you pay more for it. Read the warranty terms carefully: does it cover parts only, or does it include labor if the engine fails and has to be removed and replaced? Some warranties are parts-only, meaning you pay for removal and reinstallation if something goes wrong.

Used long blocks rarely come with a warranty. Some salvage yards offer a 30-day money-back may provide or a 30-day parts warranty, but that is the exception. If a used engine fails six months after installation, you have no recourse. This is why used long blocks are only practical if you can afford to lose that money or if your car is old enough that the risk is acceptable.

A long block is usually cheaper than a full engine rebuild but more expensive than a used engine

When your engine fails, you have three main paths: rebuild your current engine, buy a long block, or buy a complete used engine. A rebuild means a machine shop disassembles your engine, replaces worn parts, and reassembles it in your car. This can cost $2,000 to $4,000 or more, takes several weeks, and you are working with your original block — if it is cracked or damaged beyond repair, a rebuild is not possible.

A long block costs less than a full rebuild if you buy remanufactured or used, and it is faster — installation is usually one to two days instead of weeks. The trade-off is that you are removing your old engine entirely and installing a different one, which carries its own risks if the new engine has hidden problems.

A complete used engine (long block plus all accessories already installed) costs about the same as a long block but saves you the labor of transferring accessories. However, you are paying for parts you may not need, and if the accessories are worn, you are inheriting that wear. Many people prefer to buy a long block and transfer their own newer accessories.

Frequently Asked Questions

Can I install a long block myself if I have basic mechanical skills?

Engine removal and installation requires a hoist, engine stand, and specialized tools. If you have done this before, you may be able to do it. If you have not, the risk of damaging the new engine or your car's frame during removal is high. Most people should have a professional mechanic do this work.

What if the long block I buy fails after installation?

If it is new or remanufactured and still under warranty, contact the supplier or manufacturer and explain the failure. They will typically replace the engine or refund your money. If it is used and out of warranty, you have no recourse — this is why warranty matters when buying a long block.

Do I need to replace my oil and coolant after a new long block is installed?

Yes. The mechanic will drain your old fluids before removing the engine and refill with fresh oil and coolant after the new engine is installed. Some shops include this in the labor cost; confirm before work begins.

How long does a remanufactured long block last?

A properly remanufactured long block should last as long as a new one — typically 150,000 to 200,000 miles or more — because worn parts have been replaced and the engine has been rebuilt to factory specs. The quality depends on the rebuilder, so buy from a reputable shop or through a dealership.

What happens to my old engine after it is removed?

Most shops will haul it away for you, usually for a small fee or as part of the labor charge. Some salvage yards will buy your old engine from you if it can be rebuilt or parted out, though the payout is usually modest. Ask your mechanic what they do with old engines before work begins.