Can you 3D print car engine parts?

By Asked 3D Content TeamPublished Last verified

Can you 3D print car engine parts?

Not the parts inside the engine. Pistons, valves, head gaskets and timing parts see combustion heat and pressure no desktop filament survives, and carmakers that print them use metal. Off the engine, clips, brackets and covers can work in carbon-fiber nylon. Its heat deflection temperature clears the 125 °C (257 °F) engine-area rating; polycarbonate, ABS and PETG fall short.

The temperatures under the hood

Location Temperature What sets it
Passenger compartment (for comparison) up to 100 °C (212 °F) USCAR connector class T2
Engine area, off the engine up to 125 °C (257 °F) USCAR connector class T3; TXL wire, “the grade used for most underhood applications,” is rated 125 °C
On the engine up to 150 °C (302 °F) USCAR connector class T4
Exhaust manifold surface 250 °F (121 °C) at 30 mph on a level road to 1,020 °F (549 °C) at 70 mph up a 7 % grade Measured on four vehicles
Air in the engine bay after you park climbs almost 40 °C further, 3 to 24 minutes after shutdown Wind-tunnel heat-soak study

Class ratings come from the SAE/USCAR-2 temperature classes as stated in Molex’s connector table, TE Connectivity’s Generation 50 guide (T2, 100 °C) and a Delphi connector drawing (T3, 125 °C; T4, 150 °C), plus Auto Service World’s wire-grade guide. Manifold figures are from the University of Washington’s Vehicle Fire Investigation pages, and heat soak from Khaled et al. (2015). A class rating is the worst case a supplier designs for. Many spots in the bay run cooler.

The heat deflection temperature (HDT) is where a loaded test bar starts to bend. Manufacturer figures at 0.45 MPa are 71 °C (160 °F) for Bambu Lab PETG Basic (glycol-modified PET), 93 °C (199 °F) for Prusament ASA (acrylonitrile styrene acrylate), 112 °C (234 °F) for Bambu Lab PC (polycarbonate) and 186 °C (367 °F) for Bambu Lab PA6-CF (carbon-fiber nylon 6). Fillamentum ABS Extrafill (acrylonitrile butadiene styrene) lists 81 °C (178 °F) at 1.8 MPa. Only PA6-CF clears the 125 °C engine-area class. At the 1.8 MPa load (164 °C) it clears the 150 °C on-engine class by a slim margin. The full table, with glass transition temperatures (Tg) and both test loads, is on which filament survives a dishwasher.

Why internal engine parts are out of reach

Inside the engine, parts carry combustion pressure, spin at engine speed, or seal hot oil and coolant. A printed part is weakest across its layers, and the exhaust manifold next door was measured at up to 549 °C, about three times the highest HDT above.

When carmakers do print engine internals, they print metal. In 2020 Porsche, MAHLE and Trumpf printed aluminum pistons for the 911 GT2 RS engine from metal powder by laser metal fusion (LMF). Porsche says they weigh 10 % less than the forged production pistons and allow up to 30 PS more from the 700 PS engine. MAHLE, which developed the aluminum alloy, reports that six of them completed 200 hours of endurance testing on the test bench.

Which engine-bay parts you can 3D print

Plastic parts that hold nothing but their own weight and sit away from the engine block and exhaust:

  • clips and push-pins on engine covers and splash shields
  • wiring-loom brackets and cable-tie mounts on the inner fender
  • fuse box and relay box covers
  • brackets for reservoir bottles (the bracket, not the cap or the bottle)
  • air-box ducting on the cold side, between the grille and the filter

Do not print:

  • anything in the fuel system: lines, fittings, fuel-rail parts, filler parts
  • anything holding oil, coolant or brake fluid, including caps, filler necks and filter housings
  • anything near the exhaust manifold, turbocharger or catalytic converter
  • intake parts after the turbo, where the air is under boost
  • belt-drive, timing and pulley parts

A fuel or oil leak in the engine bay drips onto exhaust surfaces measured at 250 to 1,020 °F. That is a fire risk, not a broken clip.

Material choice follows the location. PA6-CF is the only filament here rated above the 125 °C engine-area class. PC and ASA can work in spots you have measured well below their HDT, such as the cold-air duct near the grille. PETG and ABS sit below even 100 °C, so keep them out of the engine bay.

An engine bay drawn as blocks, with the hot engine and exhaust in the middle and printable parts out at the edgesPrintable parts sit away from the engine block and exhaust, like a loom bracket on the inner fender or the cold-air duct by the grille.1Exhaust manifold4Loom bracket on the inner fender3Cold-air duct by the grille2Engine block
  1. Exhaust manifold
  2. Engine block
  3. Cold-air duct by the grille
  4. Loom bracket on the inner fender
Printable parts sit away from the engine block and exhaust, like a loom bracket on the inner fender or the cold-air duct by the grille.

Nylon absorbs water from the air: the PA6-CF sheet lists 2.35 % saturated uptake, so dry the spool before printing. PC and ASA warp without an enclosure. The replacement parts guide covers the layer-strength limits that apply on top of heat.

On warranty, a printed clip or bracket does not by itself cost you US coverage. The FTC says the Magnuson-Moss Warranty Act generally bars a warrantor from conditioning coverage on its own branded parts. A company may still refuse coverage for damage the unauthorized part caused.

How to check a printed engine-bay part

  1. Measure the spot first. Drive until the engine is fully warm, with some highway in the mix. Park and read the mounting surface with an infrared thermometer right away. Read it again every few minutes for about 25 minutes, because the heat-soak study found temperatures still rising 3 to 24 minutes after shutdown. Take the highest reading.
  2. Pick the material whose HDT sits well above that peak, using the 1.8 MPa figure where the sheet gives both.
  3. Heat-test a spare print. Heat it through at your peak reading in an oven you do not use for food. Press it while hot. Any give or warp means it will fail in the car.
  4. Fit the part, then check it after the first hot drive and again after a week: look for sag, warp, whitening at the layers and loose fasteners.
  5. If a printed part sags or cracks, move to the next material up the HDT list, or buy the factory part.

Sources

  1. Molex Rugged and Reliable Interconnect Products for Transportation (DigiKey TechForum) (accessed October 13, 2026)
  2. Generation 50 Portfolio Terminal and Connector System quick reference guide (TE Connectivity, via TTI) (accessed October 13, 2026)
  3. Connector drawing K29002, SAE/USCAR-2 temperature class validations (Delphi, via Mouser) (accessed October 13, 2026)
  4. Untangling Automotive Wiring (Auto Service World / CARS Magazine) (accessed October 13, 2026)
  5. Surface Temperatures: Underhood (Vehicle Fire Investigation, University of Washington) (accessed October 13, 2026)
  6. Analysis and modeling of the thermal soak phase of a vehicle: temperature and heat flux measurements (Khaled et al., International Journal of Automotive Technology 16(2), 2015) (accessed October 13, 2026)
  7. Bambu Filament Technical Data Sheet V3.0, PETG Basic (accessed October 13, 2026)
  8. Fillamentum ABS Extrafill Technical Data Sheet (accessed October 13, 2026)
  9. Prusament ASA Technical Datasheet, Version 1.1 (Prusa Polymers) (accessed October 13, 2026)
  10. Bambu Filament Technical Data Sheet V2.0, PC (accessed October 13, 2026)
  11. Bambu Filament Technical Data Sheet V3.0, PA6-CF (accessed October 13, 2026)
  12. Innovative pistons from a 3D printer for increased power and efficiency (Porsche Newsroom) (accessed October 13, 2026)
  13. MAHLE produces high-performance aluminum pistons using 3D printing for the first time (MAHLE Newsroom) (accessed October 13, 2026)
  14. FTC staff sends warranty warnings (FTC Business Blog) (accessed October 13, 2026)
  15. FTC Staff Warns Companies that It Is Illegal to Condition Warranty Coverage on the Use of Specified Parts or Services (Federal Trade Commission) (accessed October 13, 2026)