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RD
RD, ASE Certified Technician
Category: Car
Satisfied Customers: 1942
Experience:  Ase Master 35 years
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Can I exchange a Chevy 3.1 motor for a 3.8 motor

Customer Question

1999 Monte currently has a 3.1. Motor is shot and I need to replace.
Submitted: 10 years ago.
Category: Car
Expert:  RD replied 10 years ago.

Hello welcome to JA

Yes you can swap out the 3.1 to the 3.8 series 2 engine

this would be found in
  • Buick Le Sabre
  • Buick Park Avenue
  • Buick Regal
  • Buick Riviera
  • Chevrolet Camaro
  • Chevrolet Impala
  • Chevrolet Lumina LTZ
  • Chevrolet Monte Carlo
  • Holden Commodore (VS, VT, VX, VY, VZ)
  • Oldsmobile Eighty-Eight
  • Oldsmobile Intrigue
  • Oldsmobile LSS
  • Oldsmobile Ninety-Eight
  • Pontiac Bonneville
  • Pontiac Firebird
  • Pontiac Grand Prix
  • this engine was used from 1995 to 2002
  • Let me know if i can help more!

    Hart

    RD and 4 other Car Specialists are ready to help you
    Customer: replied 10 years ago.
    Will I need to change any other parts to get this to line up and operate correctly?
    Expert:  RD replied 10 years ago.

    Hello

    the motor will bolt in place

    you will need to change out the sensors and motor mounts from the 3.1 to 3.8

    Other then that from my engine swap book you are good to go on this

    Hart

    Customer: replied 10 years ago.
    Relist:
    Will I need to change any other parts on car to have the engines *fit/operate* correctly?
    Expert:  RD replied 10 years ago.

    Hello

    the motor will bolt in place

    you will need to change out the sensors and motor mounts from the 3.1 to 3.8

    Other then that from my engine swap book you are good to go on this

    Hart

    Customer: replied 10 years ago.
    Does that mean that the intakes need to be swapped also?
    Can current wiring harness and ECM remain in my 1999 Monte or do these need to be changed also?
    Also...define series 2 engine please.
    Expert:  RD replied 10 years ago.

    Hello

    3.8 series 2 engine was built from 1995 to 2002

    2003 the 3.8 was called series 3

    you wont need to swap intakes the current ecm/pcm will work with the engine swap wiring harness will be ok in the car

    Hart

    Customer: replied 10 years ago.
    I am confused...if I swap engines...keep wiring harness and intakes...how are the sensors going to match up...it appears the location of the sensors on a 3.1 vs 3.8 are not the same
    Example...coil pack is on firewall section of 3.1 and on radiator side/front side of a 3.8
    Mass airflow is another issue...different locations within the air intake
    Expert:  RD replied 10 years ago.

    Hello

    Yes i do see this also and on the foot notes It says some wires are to long and some wires are to short , Extend and shorten wires as needed, or you can replace the engine harness with a 1999 3.8

    But cross checking the electoral part numbers the 3.1 3.4.3.8 shows the same part number for the engine harness

    ILl make a cpl of phone calls in the am and see what others say I know 2 people who have done this swap and see what they ran into

    Hart