I’ve been burned on used motors more times than I’d like to admit. One looked spotless, fresh coat of paint, even had the “ran when pulled” scribbled across it in greasy marker. Bolted it in, turned the key, and the thing knocked like a woodpecker on steroids. Another time, I trusted some guy’s word on mileage. “Only 60k,” he said. Yeah right. That motor was more worn out than my old shop boots.
Point is—if you’re out there searching “used motor for sale,” you better know what you’re walking into. It’s not like buying spark plugs or a new battery. You’re gambling with the heart of your car. Get a bad one, and you’re right back to square one with an empty wallet and a car that won’t move.
So here’s how I approach it, straight from someone who’s dragged plenty of greasy lumps out of junkyards and Craigslist listings.
Don’t Buy Blind
First rule: never buy a motor without hearing it run. If you can’t hear it run, you at least need compression numbers, a leak-down test, or something solid. Sellers love to say “ran when pulled.” That phrase is basically junkyard code for “we have no idea if this thing works, but maybe it did once.” I’ve learned that lesson the hard way.
If you’re at a yard that pulls the engine before you get there, ask if they have video proof of it running in the donor car. A lot of the better yards do this now. If they don’t, you’re taking a risk.
Mileage Matters (but don’t trust the seller blindly)
Everyone swears their motor has “low miles.” I swear I’ve seen a dozen motors “with 80k” that looked like they went cross-country 20 times. Always check the donor vehicle if you can. VIN numbers can tell you a lot. Some yards will even give you the odometer reading before they yanked the engine.
Anything over 150k miles, I personally stay away from unless it’s dirt cheap and I just need something to get a beater rolling. Under 100k is where you want to be if you plan to keep the car around for a while.
Look at the Motor Like a Detective
Pop off the oil cap—sludge? Walk away. Pull the dipstick—milky oil? That’s coolant mixing in, probably blown head gasket or worse. Look at the spark plugs if they’re still in—uneven wear tells you a lot. Check the block and heads for cracks. Even tiny ones.
Sometimes you’ll see fresh paint or shiny gaskets. Don’t let that fool you. That can be someone’s way of dressing up a tired motor. I’d rather buy an engine that looks filthy but honest than one that looks like it just rolled out of a showroom.
Ask About Warranty
Good salvage yards will give you some kind of warranty. Maybe 30 days, maybe 90. That’s your safety net. If they offer zero warranty, think twice. Yeah, it might be cheaper, but if you get stuck with a boat anchor, you’ve got no recourse.
One of the best motors I ever bought came with a six-month warranty. That yard pressure tested it, tagged it, and backed it up. I dropped it in, and the thing ran like a champ for years.
Price Check
Used motor prices swing all over the place. You’ll see one for $400 and another for $1,500, same make and model. The difference usually comes down to mileage, warranty, and the reputation of the yard or seller. Don’t just grab the cheapest one. Factor in the cost of swapping it out too. Paying an extra couple hundred bucks for a motor you know is solid can save you double that in headaches later.
Red Flags I’ve Learned to Spot
Seller won’t give you a VIN or mileage.
“Ran when pulled” but no proof.
Oil cap looks like chocolate milk.
Motor’s been sitting outside in the rain uncovered.
Price sounds too good to be true (because it usually is).
My Two Cents
Buying a used motor isn’t the worst idea in the world. In fact, it’s saved me and a lot of buddies thousands of dollars compared to going new or rebuilt. But it’s not something you rush into. Take your time, ask questions, and don’t let a slick seller pressure you.
At the end of the day, you want a motor that’ll fire up, hold pressure, and get you down the road without drama. If you find one with low miles, clean oil, good compression, and some kind of warranty, you’ve struck gold.
Everything else? Roll the dice if you want. Just be ready for whatever comes out of that gamble.
