How to check a used engine before you buy
Before you buy a used engine, do four things: match the engine code stamped on the block to your exact car, ask why the donor car was broken, inspect the unit for seizure, cracks and leaks, and confirm exactly what is included with it. An engine is the highest value part on the car, so a careful ten minutes here saves a very expensive mistake. A genuine used engine from a known donor car goes in like the original and costs a fraction of a new or reconditioned unit. This is the checklist we work through ourselves.
Why is the engine code more important than the model?
One model is usually sold with several engines, and even engines of the same size can differ in fuel system, emissions equipment, gearbox mounting and electronics. A 2.0 TDI in a VW group car might be a BKD, a BMR, a CGLC or several others, and they are not interchangeable even though the badge on the boot reads the same. The engine code is stamped on the block, printed on a sticker on the timing cover or cam cover, and recorded in the service book. Find yours before you shop, check it against the code in our listing title, and most of the risk disappears. Our engine codes page explains where to look on common makes, and if you cannot find it, send us your registration and we will identify it.
| Make | Code format | Example from our recent stock |
|---|---|---|
| Audi, VW, Seat, Skoda | Three or four letters | BKD, BMR, CGLC, CAYC, CGGB |
| BMW | Letter, two digits, then variant | N47D20C |
| Mercedes | OM or M plus three digits | OM651, OM640 |
| Ford | Four letters | TXDA, T1DA |
| Peugeot, Citroen | DV or EP plus letters | DV6C, DV6FC |
| Hyundai, Kia | Letter, digit, letters | D4FD |
What should I ask about the donor car?
Ask why the car was broken. An engine from a car written off for accident damage, flood free, or scrapped for an electrical or gearbox fault was running up to the day it stopped, and that is what you want. An engine pulled because it failed is a different proposition and should be sold as such, usually as a block or for parts. A breaker who dismantles cars knows the donor's story; a trader who buys engines in bulk often does not. We break every car ourselves at our Doncaster yard, so we can tell you the donor model, year and reason for breaking on any engine we list. Treat vague answers as a warning sign.
What can be checked on an engine that is out of the car?
More than people expect. The crank should turn freely by hand on the pulley bolt, with no tight spots or seizure. The block and head should be free of cracks and welds, and the mating faces should not show heavy coolant staining. Take the oil filler cap off: clean metal underneath is a good sign, while thick cream coloured sludge points to coolant in the oil and possible head gasket trouble. Look at the sump and the rear main seal area for fresh oil. Pull a glow plug or spark plug if you can and check the tip. If the engine was run before removal, as ours often are, the listing will say so. What cannot be confirmed off the car, an honest seller admits rather than guesses.
What exactly is included with a used engine?
"Engine" means different things to different sellers, so read the listing title and photos carefully. A bare block is the block and crank only, with or without pistons. A short engine adds the pistons and rods. A long or bare engine adds the cylinder head. A complete engine usually includes the manifolds, injectors, fuel pump and often the turbo and alternator, but not always the flywheel, clutch or gearbox. Our titles state whether the unit is complete or a block, and whether it came from a manual or automatic car, because flywheels and some sensors differ between the two. Confirm what is included before you buy so you are not chasing a missing injector loom on the day of fitting.
What should I replace while the engine is out?
Fitting an engine is a big job, so do the cheap jobs at the same time. Fit a new timing belt or inspect the chain and tensioner, replace the water pump, thermostat and auxiliary belt, and change the oil and filter. Clean the breather, and on a diesel check the EGR valve and inlet for heavy carbon. Replace the rear main seal and sump gasket if they weep, because they are inaccessible once the engine is in. Keep your old ECU if the immobiliser is coded to it, unless you can recode. Our guide to engine and gearbox transplants covers the swap in more detail.
Will a used engine from a different model fit?
Often yes, if the engine code matches, because manufacturers share engines across their range. The N47 in a BMW 1 Series is the same family as the one in a 3 Series and an X1, and VW group diesels appear in Audi, Seat and Skoda models under the same code. What changes is the ancillaries: sump, mounts, inlet pipework and sometimes ECU software. Compare the code first, then check the sump and mount positions against your old engine before you commit. Our BMW N47 engine guide works through a real example of this.
What we usually have in stock for used engines
Stock changes daily as cars come in and engines sell, so the engine and fuel collection shows what is live right now. Complete engines and blocks we have listed recently include:
- Audi Q5 A4 A5 A6 2.0 TDI manual engine, complete, CGLC
- VW group 2.0 TDI automatic engine, BKD
- VW Passat 2.0 TDI manual engine, BMR
- Audi A6 3.0 TDI quattro manual engine, ASB
- Ford Kuga 2.0 TDCi 4x4 automatic complete engine, TXDA
- Citroen C4 1.6 HDi complete manual engine, DV6C
- BMW N47D20C 2.0 diesel engine block, 7811138
- Mercedes B180 W246 1.8 diesel engine block, R6510111201
- VW group 1.6 TDI manual engine block, CAYC 03L103021BK
- Hyundai i40 1.7 diesel bare engine block, D4FD
We also list crankshafts, oil pumps, sumps, manifolds and wiring harnesses from the same engines. If yours is not showing, send us your registration and the engine code and we will check the yard and tell you what is coming in.
Buy with confidence
Every engine we sell comes off a known donor car at our Doncaster yard, is inspected before listing and is photographed so you see the actual unit, not a stock image. Tracked UK delivery is included on every order and is free on most parts; panels, engines and gearboxes carry a charge shown on the product page. Order before 2pm on a working day for same day dispatch. If a part is not right, you have 30 day returns. Send us your registration and the part you need and we will confirm fitment before you buy. Parts worth your trust.
Frequently asked questions
How do I make sure a used engine fits my car?
Match the engine code stamped on the block to the code in the listing, not just the model name, because one model can carry several engines with different fuel systems, mounts and electronics. Find your code on the block, the timing cover sticker or the service book. If you are unsure, send us your registration and we will confirm the correct unit before you buy.
What should I ask about a used engine's history?
Ask why the donor car was broken. An engine from a car written off for accident damage or scrapped for an electrical or gearbox fault was running when it came off the road. One pulled because it failed should be sold as a block or for parts. We break every car ourselves, so we can tell you the donor's story.
Can a removed engine be checked?
Yes. The crank should turn freely by hand with no tight spots, the block and head should be free of cracks, the oil filler cap should be clean underneath rather than coated in cream coloured sludge, and the seals should not be weeping fresh oil. If the engine was run before removal, the listing should say so. An honest seller states what was and was not confirmed.
What is included with a used engine?
It varies. A bare block is block and crank only, a short engine adds pistons and rods, a long engine adds the head, and a complete engine usually adds manifolds, injectors and pump, sometimes the turbo. Flywheel, clutch and gearbox are normally separate. Read the title and photos and ask before you buy.
What if the used engine is not right?
Every order from Partsworth comes with 30 day returns, so if the engine does not match or is not as described you are covered. To avoid the problem in the first place, send us your registration and the engine code before ordering and we will confirm fitment for your exact car.