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Used Engine Warning Questions You Should Ask Before Buying One

Should you buy a $500 “good used engine” over a rebuilt or new engine that will cost thousands? Here’s one important warning you need to know about this. Plus, the minimum you need to look for in a used engine.

Whether it’s a relatively recent model in nearly impeccable shape or a special model you’ve enjoyed and want to keep for another few years, a blown engine replacement can be a difficult question when you weigh in the costs of buying and having a rebuilt engine with a warranty or a new engine from the manufacturer installed by a mechanic.

However, there is another option―buying an advertised “good used engine” for only a few to several hundred dollars. But is this really a good idea?

A Used Engine Warning

In a recent car engine warning episode from the Car Wizard YouTube channel, the advice given is that before considering even buying a used engine to save money, you need to ask yourself this one question before going any further with the option: Are you comfortable with the fact that 9 out of every 10 “good used engines” are actually bad?!

 According to the host of the channel, that is the number he sees whenever someone decides to take a chance on buying an advertised “good used engine” online or from a junkyard dealer. Only 10% of the time will you wind up with a truly good engine the first time around during a search and purchase.

Problems with “Good Used Engines”

The real problem with “good used engines” is that the majority of them pertain to modern cars that really were not designed to be rebuilt like many models from the 1970’s and earlier. In other words, that “good used engine” of today is like a cat with only one life compared to an earlier time when an engine’s life technically could be rebuilt multiple times depending on the amount of iron between the cylinders.

Putting it in another way, modern engines are single-use, throwaway products.

The point being, if you are stuck with a bad “good used engine” there is no reasonable fixing (i.e., rebuild option) of the engine to make the best of a bad situation. You will have to try to get replacement or reimbursement for the bad “good used engine” and hope the next one is a winner or that your money is refunded, respectively.

In all likelihood you may never see that refund and you will have lost months (if not years) toward getting that car back on the road.

For a good explanation of how bad this problem is, here is video where the Car Wizard advises viewers to never buy a “good used engine”!

Why Can’t I Get a Good USED Engine? What's Going On?


What Should I Look For in a Good Used Engine?

If you’ve decided to go with buying a “good used engine” despite the host’s warning about this engine replacement option, there are some minimum precautions or checks you should make before paying someone to install it in your car:

  1. Give the engine a thorough visual examination making sure all of the parts (including the wiring harness) are present. Do not accept any engine that appears to have been scavenged for any components (starter, fuel pump, power steering, etc.); when any parts are missing it is a red flag that this is not a good used engine.
  2. Check the coils for any signs of cracks and the spark plugs for excessive wear or fouling.
  3. Check the condition of the engine oil: Is it thick and gunky from not having ever been changed or is it too thin possibly diluted with gasoline due to cylinder washing? Do you see any milky streaking in the oil indicating a blown head gasket with coolant seeping into the engine?
  4. Physically turn the engine with a socket and breaker bar with the spark plugs removed to ensure the engine turns freely. If it is difficult to turn, then something is amiss internally such as engine bearings, gears, or pistons that are binding and inhibiting movement.
  5. Use an inspection camera with a flexible goose neck to peer into the cylinders through the spark plug holes. Look for signs of scoring on the cylinder walls, pitting or burning of the valves and the piston head. Some darkening of the piston heads is normal, but if you see one or two piston heads that are squeaky clean compared to the others, this is a sign of coolant having gotten into the cylinder and steam cleaned the piston heads.
  6. Buy a “good used engine” only from a reputable seller.

Should You Choose the “Rebuilt Engine” Option?

Deciding to go with a rebuilt engine is a better option; however, it does cost significantly more than a used engine and it has its own problems―chief of which is sellers who use the terms “rebuilt” and “reconditioned” interchangeably to confuse and con the buyer.

A rebuilt engine is one that has been returned to its OEM specifications where:

  • The engine is completely disassembled, and all components are cleaned and inspected.
  • Every component is measured and tested.
  • Worn components such as the pistons, rings, bearings, camshaft, or crankshaft are replaced.
  • Machining work such as boring and honing of cylinder walls is usually done to restore the engine to its new recommended specs with a rebuild.
  • The engine is then reassembled with its new or re-machined parts and tested to ensure it meets original performance standards.
  • Generally uses parts that meet or exceed OEM specifications, including both new and re-machined parts.

However, a “reconditioned” engine is a significantly less thorough process toward ensuring an engine is ready for installation into a car. A reconditioned engine is one that has been inspected, cleaned, and repaired as necessary to restore it to good working condition, but not necessarily to new or rebuild-recommended spec condition.

A reconditioned engine will undergo:

  • Disassembly with all parts cleaned, inspected, and some possibly replaced.
  • Replacement parts might be OEM, but more likely cheaper aftermarket parts.
  • Reassembly with some testing to ensure it meets certain performance standards e.g., it turns on and runs without excessive engine noise or blowing up.

The biggest problem is that a reconditioned engine might be just fine, but it is really dependent upon the competence of the mechanic and the level of work done. Both of which can and do vary significantly from one engine provider to another.

The point made is that you have to ask the source of the “rebuilt” engine if it meets the definition of a true rebuild or is it closer to a reconditioning.

In either case, at the very least be sure to get a warranty in writing in case the engine should fail shortly afterward.

For additional articles related to car engine warnings, here are a few for your consideration:

Timothy Boyer is an automotive reporter based in Cincinnati. Experienced with early car restorations, he regularly restores older vehicles with engine modifications for improved performance. Follow Tim on Twitter at @TimBoyerWrites  and Facebook for daily news and topics related to new and used cars and trucks.

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Image source: Deposit Photos