Buying guide
5 Tips for Buying Used Japanese Car Engines
By NAPA Auto Parts Team · · 7 min read
Quick answer
Match the engine code to your car. Check the miles and the listing details. Know what parts come with the engine. Ask questions before you pay. Plan for small parts during the swap. Then contact NAPA Auto Parts to confirm the engine suits your vehicle.
This guide gives you five clear tips for buying a used Japanese car engine with less stress. You will learn what to check, what to ask, and what to plan. We keep it simple, honest and easy to follow.
Why do people look for used Japanese engines?
Many car owners search for used engines from Japanese brands. Honda, Toyota, Mazda and Subaru are common names in that search.
A used engine can be a smart way to keep a car on the road. It can also go wrong if you rush. These five tips help you slow down and buy with care.
The tips work for any used engine, not just one brand. Right now, the example listings in this post are BMW and Ford engines. We use them to show you how to read a listing.
Start on our used engines page to see what is listed. You can also browse Honda engines or Toyota engines.
Tip 1: Match the engine code, not just the car name
An engine code is a short name for one exact engine. It is made of letters and numbers. Two cars with the same name can have different engines.
So do not shop by car name alone. Match the engine code first.
Look at this BMW E90 N51 engine listing. The title gives the engine code, N51. It also says RWD, which means rear wheel drive. Small details like these help you compare.
Write down your own details before you shop:
- Your engine code, if you know it
- Your car year, make and model
- Your VIN, which is the vehicle identification number on your dash and door sticker
- Whether your car is front, rear or all wheel drive
If a listing leaves out the code, ask why. Then contact NAPA Auto Parts to confirm the engine suits your vehicle.
Tip 2: Read the miles and the listing details
Miles tell you how far the engine has run. Fewer miles sounds nice. But care matters too. An engine that got oil changes on time can beat one that was ignored.
Listings often show miles in short form. A number like 171k means 171 thousand. One example is this BMW E39 530i M54B30 long block listing. Another listing in our shop shows 241,935 miles on a Ford Explorer Sport Trac engine.
Use the miles as one clue, not the whole story. Read the rest of the listing too:
- Is the engine code clear?
- Are the photos clear?
- Does the listing say what is included?
- Does it say how the engine ran, if that is known?
Never guess. If something is missing, ask.
Tip 3: What is the difference between a long block and a complete engine?
This one trips up many buyers. The words sound alike, but the parts are not the same.
A long block is the main part of the engine. It has the engine block, the cylinder heads and the moving parts inside. Many outside parts may be missing.
A complete engine usually has more outside parts. These can include things like the intake and some sensors. But each seller lists it a little differently.
So ask for a list of what is included. Then compare it with what your car needs. Missing parts add time and work to your swap.
Titles can give you a hint. One listing says Long Block Assy, and Assy is short for assembly. Another says Complete Engine. Read the title, then ask for the details.
Tip 4: Ask the right questions before you buy
A good seller answers plain questions. Ask before you pay, not after.
Here are good ones to start with:
- What is the exact engine code?
- What are the miles, if known?
- What parts come with the engine?
- Can I see clear photos of the engine?
- Is there any note on how the engine ran?
- Which cars is this engine meant for?
You want clear answers. If you hear a vague answer, pause and ask again.
Some owners also ask about compression. That is how well each cylinder squeezes air and fuel. Ask a shop if a compression check makes sense for your job.
Tip 5: Plan the swap and replace small parts
A swap means taking out the old engine and putting in the new one. Good planning saves you trouble later.
- Find out why the old engine failed. Fix that cause first, or the new engine may fail too.
- Make a parts list. Compare the old engine with the new one side by side.
- Replace small wear parts while the engine is out. Think belts, hoses, seals and gaskets. A gasket is a thin seal between two metal parts.
- Use fresh oil, a new filter and fresh coolant.
- Drive gently at first. Watch your gauges and look for leaks.
Extra work like this is normal with any used engine. It helps the engine last longer.
What should you do next?
Pick out your engine code. Find your VIN. Then write your list of questions.
Next, browse the engines page and read each listing slowly. Compare the code, the miles and what is included.
Own a Ford too? These pages may help you: Used Ford Expedition engines and the Ford 5.0L Coyote V8 plain guide.
Before you order anything, contact NAPA Auto Parts to confirm the part suits your vehicle. We would rather answer your questions now than have you worry later.
Take your time. A calm buyer makes a better choice.
Parts that can help
*CORE* OEM BMW E90 E92 N51 COMPLETE ENGINE MOTOR N51B30A RWD 206k Ran! $499.95
✅ 01-03 OEM BMW E39 530i M54B30 3.0L I6 RWD Engine Motor Long Block Assy 171k $995.00
02-04 FORD EXPLORER SPORT TRAC ENGINE MOTOR 4.0 NO CORE CHARGE 241,935 MILES $399.99
06-10 BMW E60 E63 E64 E65 550 650 750 N62 4.8L V8 Engine Motor Assembly OEM 98K $800.00
07-09 BMW 335xi E90 AWD 3.0L I6 N54B30 Complete Engine Motor Assembly 192K 2732 $879.99
08 09 10 BMW 528I 3.0L ENGINE 90 DAY WARRANTY $750.00
Frequently asked questions
What is the first thing to check when buying a used engine?
Check the engine code. It names the exact engine your car needs. Two cars with the same name can use different engines. Then contact NAPA Auto Parts to confirm the engine suits your vehicle.
How do I find my engine code?
Look in your owner's manual or on the engine itself. Your VIN, the vehicle identification number, can also help. If you are not sure, contact NAPA Auto Parts to confirm before you order.
Does lower mileage always mean a better used engine?
No. Miles are one clue. Care matters too, such as oil changes on time. Read the whole listing and ask questions. Contact NAPA Auto Parts to confirm any detail the listing does not make clear.
Is a long block the same as a complete engine?
No. A long block is the main engine with the block, heads and inner moving parts. A complete engine usually has more outside parts. Ask what is included before you buy.
Should I replace small parts during an engine swap?
Yes, it is a smart idea. Belts, hoses, seals and gaskets are easy to reach while the engine is out. Fresh oil and coolant help too. A trusted shop can help you plan.
Can NAPA Auto Parts confirm that an engine suits my car?
Please contact NAPA Auto Parts with your VIN, car year, make and model. We can help you confirm the match. Do not assume an engine fits because the car names look alike.
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