BMW I3 gasoline (range extender, Rex) - Engine (2014-2020)
VIN-VERIFIED UNIT
✓ Actual photos of the exact unit you'll receive — not a stock image
✓ Confirmed Fitment — fits these vehicles
  • I3 Gasoline Range Extender Rex 2016, 2019, 2018, 2020, 2014, 2015, 2017
Enter your VIN below and we’ll confirm the exact fit before we ship.
Engine · Tested

BMW I3 gasoline (range extender, Rex) - Engine (2014-2020)

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Confirm it fits YOUR vehicleEnter your VIN — we verify exact fit before you pay
Find your VIN on the driver-side door jamb or lower windshield.
Unit Condition & Specs
AvailabilityIn stock — ready to ship
55% OFF $6,212.80
$2,824.00
Mileage
Learn more →
✓ Flat-rate freight — insured & tracked ·✓ 90-day warranty included· freight shown at checkout: $250 commercial / $400 residential
Ships within 3 - 5 business days Approx - flat-rate freight, tracked & insured Most orders arrive 5–7 business days after dispatch (US). You get tracking the moment it ships.
Not sure it fits? Call an expert
🛡90-Day WarrantyParts replacement
🚚Flat-Rate FreightDelivered to your door
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↩24-Hr Free CancelFull refund within 24h

How ordering works

  1. 1Enter or confirm your VIN
  2. 2We verify exact fitment for your vehicle
  3. 3Flat freight shown up front — no surprises
  4. 490-day warranty included on every part
  5. 5We photograph & confirm the unit before it ships
What you're getting

What's included with this engine

You're buying a complete engine assembly — not a bare block. Here's exactly what arrives bolted to it, and the handful of accessories your mechanic moves over from your current engine during the install.

✓

Included with your engine

Already assembled — ships as one unit
  • Long block — fully assembled
  • Short block
  • Cylinder head
  • Crankshaft
  • Camshaft
  • Pistons
  • Intake manifold
  • Exhaust manifold
  • Oil pan
  • Timing cover
⇄

Not included — transfer these over

Reused from your current engine
  • Wiring harness
  • Bolt-on accessories
Why these aren't included: these parts are tied to your vehicle's exact trim and options, and the ones already on your current engine are almost always in good working order. Your mechanic transfers them across during the install — that's standard practice on an engine replacement, and it keeps your price down.
Quick definition: a short block is the block, crankshaft, camshaft and pistons. A long block adds the cylinder head and valvetrain. A complete engine — what you're buying here — is the long block with the intake manifold, exhaust manifold, oil pan and timing cover already fitted.
Not sure what your install needs? Talk to a parts expert
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Part details

About this part

BMW i3 REx Range Extender Engine K37 For 2014-2020 i3 REx models

This bold 647cc 2-cylinder engine, borrowed from motorcycles, powers your i3's generator to push your range further.

Engine Specifications:

Category Details
Engine Code K37 
Displacement 647cc inline-2
Horsepower 34 HP 
Fuel System Electronic Fuel Injection
VIN Identifier 5th digit = D
Engine Rear subframe position
 

Key Features:

Complete Long Block Assembly: Includes the fully assembled engine block, crankshaft, pistons, cylinder head, and valvetrain.

Includes Intake & Exhaust Manifolds: Comes with both manifolds pre-attached, saving installation time.

Backed by Warranty: Provides a reliable warranty on the entire assembly for peace of mind.

Pricing Options:

Mileage Range Price Condition 
30K-60K miles $ 2,824.00 Like-new condition
60K-90K miles $ 2,612.00 Light use, excellent condition
90K-120K miles $ 2,406.00 Good condition, minor wear
120K-150K miles $ 2,200.04 Functional for budget repairs
 

Shipping Information:

Standard shipping 5-7 business days.

Expedited shipping are available for an extra cost.

Frequently Asked Questions?

Q: How do I confirm REx compatibility?

A: Make sure your BMW i3’s model year is 2014-2020 and check the engine’s part number against our catalog. This ensures the range extender engine fits perfectly and your ride stays powerful and reliable.

Q: What maintenance does the REx need?

A: Keep your BMW i3 REx engine strong by regularly changing the oil and filter. Also, check coolant levels and spark plugs to avoid breakdowns. This simple care keeps your range extender ready to power you further without fail.

Q: How often should I run the REx?

A: To keep your BMW i3’s range extender engine in top shape, run it regularly even if just for short bursts. This prevents fuel from stagnating and keeps all parts sharp and ready. 

Ready to Order?

Order this powerful gasoline engine for 2014-2020 models now and take control of your drive. Don't wait equip your ride with reliable performance that takes you further and dares to go beyond limits.

Order with confidence

Tested, VIN-matched, and guaranteed

✓

VIN-Verified Fit

We match the part to your vehicle's VIN and confirm exact fitment before we ship — so it fits the first time. Free cancellation within 24 hours.

⚙

Works on Arrival, Guaranteed

Every unit is tested before it ships. If it arrives defective, we replace it fast — and in the rare case we can't replace it, you get a full refund.

★

90-Day Warranty

A real parts-replacement warranty, included — with extended coverage available.

✓Real photos of the exact unitWhat you see is what ships
✓A-grade OEM, testedVerified specs, not estimated
✓VIN-matched to your vehicleConfirmed before dispatch
Shipping & delivery

Heavy freight item, shipped fully insured and tracked. Freight is a flat $250 commercial / $400 residential, shown at checkout — no hidden fees, no freight-quote runaround.

1Ships within 3 - 5 business days ApproxCarefully packed & dispatched from our US warehouse
2Freight to your doorBrought to your door
3Delivered in 5–7 business daysTracked & insured · tracking sent when it ships
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