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What to Look for When Buying a Used Car Engine

Whether you're restoring that '67 GTO or just trying to get your Civic back on the road, finding the right salvage engine often requires a lot of shopping around. By keeping a couple things in mind, you can make the process a lot easier. Here's a few things to look for when you're buying a used car engine.

Have Your Information Ready

Before you start your search for a good engine, have your own vehicle's VIN on hand — this will help the seller understand exactly what you need. Make sure you know your engine’s size as well — look for the liter size on your current engine's valve cover. When I'm on the hunt for a used engine, it's important to figure out exactly the best places to look for salvage engines near me. Junkyards can be a great resource, but you can also find used parts online.

Find out the Engine's Mileage

This is a no brainer — you'll want the newest engine possible, but odometer readings may be tricky to find. If you bring a portable starter battery, you might be able to read it from the used vehicle's dashboard. Next, look for oil change stickers or service receipts in the vehicle's pockets and the glovebox. If there aren't any, you're left guessing the mileage based on visual wear, which risks underestimating the wear and tear of the engine. While more mileage is usually a bad sign, certain gas and many diesel motors can go more than 300,000 miles when regularly maintained. That’s why it's important to…

Know the Vehicle's Service History

The best case scenario is finding a salvaged engine in a vehicle with a well-documented service history. Pay special attention to time between oil changes. Although modern oils can go 5,000-10,000 miles, don't assume salvage engines have had an ideal life. Look for intervals around 3,000 miles if the oil quality isn't stated.

Engines from fleet-maintained vehicles are a good find, although you'll be limited to a handful of makes and models. If you can use one, you'll usually be in luck and be able to access records. If not, and you find a neat pile of receipts, thank the car gods and return the favor down the road.

Test the Engine's Oil Quality

Speaking of maintenance — when it comes to an engine, make sure the quality of the vehicle's engine oil is up to standard. If the engine oil hasn't been changed for a while, it can interfere with the engine's operation. Oil that’s less viscous causes piston and camshaft degradation, as well as other lubrication problems you won't want to deal with. That's why it's worth doing an oil analysis. Use a dipstick to check the engine oil — if it's black and slushy, then the previous owner didn't take great care of the engine, and it's probably not worth buying.

Check the Engine's Compression

Now to the nitty gritty! Before you buy an engine, make sure you can test the compression. You can get it done with a simple, inexpensive compressions tester, and you can do it yourself or have a mechanic do it.

Remove a spark plug, then insert the tester and tighten it by hand. Turn the engine over with a wrench, then read the tool. Check exact specifications — anything under 150 PSI is suspicious. And if you can, check every cylinder. Ultimately, making sure the compression level is where it should be can save you thousands down the road.

Go Forth and Conquer

Anyone who's tried to buy a used car knows that there are plenty of duds out there being sold as gold. So while you're on your search for a used engine, come well-prepared, ready to inspect, and patient. With the right knowledge, you'll know if an engine can still carry you many miles — or if you're better off carrying it to the trash. Happy hunting!


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