K05 Factory-verified

Buick · Regular Production Option

Heater, engine block

Years 1987, 1989, 1998–09, 2015–19, 2022–23, 2025–27 Models 25 Factory citations 66

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Also described as Engine block heater

Also documented for Cadillac Chevrolet GMC Hummer Oldsmobile Pontiac Saturn

Documented applications

Century — A-body (1982–1996)

1989 Single-source

Shared A-body engine code, cited from the Chevrolet Celebrity kit's 1989 order guide; the Century parts catalog (44A or 45A; not recorded which) shows the code without a date; the only dated source is the kit, so the row is single-source

GM Heritage factory kit — 1989 Chevrolet Celebrity, p.10.

Century — W-body (1997–2005)

1998–2005 Factory-verified

GM factory document — 1998 buick century rpo code list, p.1.
GM factory document — 1999 buick century rpo code list, p.1.
GM factory document — 2000 buick century rpo code list, p.1.
GM factory document — 2001 buick century rpo code list, p.1.
GM factory document — 2002 buick century rpo code list, p.1.
GM factory document — 2003 buick century rpo code list, p.1.
GM factory document — 2004 buick century rpo code list, p.1.
GM factory document — 2005 buick century rpo code list, p.1.

Enclave — C1XX (2018–2024)

2018, 2022–2023 Factory-verified

all trims: O; 2018: GM order guide via GM Authority

GM factory document — 2018 buick enclave order guide copy gm authority, p.12, p.24, p.36.
GM factory document — 2022 buick enclave order guide copy nhtsa docket, p.15, p.32.
GM factory document — 2023 buick enclave order guide copy autoevolution wayback, p.15, p.31.

Enclave — Lambda / GMT967 (2008–2017)

2008–2009 Factory-verified

GM factory document — 2008 buick enclave rpo code list, p.1.
GM factory document — 2009 buick enclave rpo code list, p.1.

Enclave — VSS-S (2025–2027)

2025–2027 Factory-verified

O on all trims

GM factory document — 2025 buick all new enclave fleet order guide, p.13.
GM factory document — 2026 buick enclave fleet order guide, p.13.
GM factory document — 2027 buick enclave fleet order guide, p.14.

Encore — Gamma II (2013–2022)

2018–2019 Factory-verified

only with the LE2 engine; 2018: Sport Touring: O; 2019: Sport Touring, Essence: O

GM factory document — 2018 buick encore order guide copy gm authority, p.23.
GM factory document — 2019 buick encore order guide copy gm authority, p.21.

Encore GX — VSS-F (2020–2027)

2025–2027 Factory-verified

Preferred, Sport Touring, Avenir: O

GM factory document — 2025 buick encore gx fleet order guide, p.14.
GM factory document — 2026 buick encore gx fleet order guide, p.14.
GM factory document — 2027 buick encore gx fleet order guide, p.14.

Envista — VSS-F (2024–2027)

2025–2026 Factory-verified

all trims: O; includes front lower grille active shutters (VRI)

GM factory document — 2025 buick envista fleet order guide rpo codes, p.1.
GM factory document — 2025 buick envista fleet order guide, p.10.
GM factory document — 2026 buick envista fleet order guide rpo codes, p.1.
GM factory document — 2026 buick envista fleet order guide, p.11.

LaCrosse — E2XX, 3rd gen (2017–2019)

2017–2019 Factory-verified

2019: all trims: O

GM factory document — 2017 buick lacrosse fleet order guide wayback, p.4.
GM factory document — 2018 buick lacrosse order guide copy gm authority, p.10.
GM factory document — 2019 buick lacrosse order guide copy gm authority, p.14.

LaCrosse — Epsilon II, 2nd gen (2010–2016)

2015 Factory-verified

2015: all groups: O

GM factory document — 2015 buick lacrosse fleet order guide wayback, p.4.

LaCrosse — W-body / GMX365 (2005–2009)

2005–2009 Factory-verified

GM factory document — 2005 buick lacrosse rpo code list, p.1.
GM factory document — 2007 buick lacrosse rpo code list, p.1.
GM factory document — 2009 buick lacrosse rpo code list, p.1.

LeSabre — H-body (1992–1999)

1998–1999 Factory-verified

GM factory document — 1998 buick lesabre rpo code list, p.1.
GM factory document — 1999 buick lesabre rpo code list, p.1.

LeSabre — H-body (2000–2005)

2000–2005 Factory-verified

Z49's includes text prints KO5 (letter O); the code is K05.

GM factory document — 2000 buick lesabre rpo code list, p.1.
GM factory document — 2005 buick lesabre rpo code list, p.1.

Lucerne — G-body (2006–2011)

2006–2009 Factory-verified

GM factory document — 2006 buick lucerne rpo code list, p.1.
GM factory document — 2009 buick lucerne rpo code list, p.1.

Park Avenue — G-body (1997–2005)

1998–2005 Factory-verified

GM factory document — 1998 buick park avenue rpo code list, p.1.
GM factory document — 2005 buick park avenue rpo code list, p.1.

Rainier — GMT360 (2004–2007)

2004–2007 Factory-verified

GM factory document — 2004 buick rainier 2wd rpo code list, p.1.
GM factory document — 2007 buick rainier rpo code list, p.1.

Regal — E2XX (2018–2020)

2018–2019 Factory-verified

2019: Regal, Preferred, Preferred II, Essence, Avenir, GS: O (2019 Sportback order guide)

GM factory document — 2018 buick regal sportback fleet order guide wayback, p.1, p.5.
GM factory document — 2018 buick regal tourx fleet order guide wayback, p.1.
GM factory document — 2019 buick regal sportback order guide copy gm authority, p.15.

Regal — Epsilon II, 5th gen (2011–2017)

2016 Factory-verified

2016: 1SL, 1SN, 1SP: O

GM factory document — 2016 buick regal order guide copy gm authority, p.12, p.25.

Regal — G-body (1983–1987)

1987 Factory-verified

not with LV2; gnttype.org's 1987 option sheet; the kit's weight page prints PPO KO5; shared G-body code, cited from the Monte Carlo kit

GM Heritage factory kit — 1987 Chevrolet Monte Carlo, p.89.

Regal — W-body (1997–2004)

1998–2004 Factory-verified

GM factory document — 1998 buick regal rpo code list, p.1.
GM factory document — 1999 buick regal rpo code list, p.1.
GM factory document — 2000 buick regal rpo code list, p.1.
GM factory document — 2001 buick regal rpo code list, p.1.
GM factory document — 2002 buick regal rpo code list, p.1.
GM factory document — 2003 buick regal rpo code list, p.1.
GM factory document — 2004 buick regal rpo code list, p.1.

Rendezvous — U-body / GMT257 (2002–2007)

2002–2007 Factory-verified

GM factory document — 2002 buick rendezvous awd rpo code list, p.1.
GM factory document — 2006 buick rendezvous awd rpo code list, p.1.
GM factory document — 2007 buick rendezvous fwd rpo code list, p.1.

Riviera — G-body (1995–1999)

1998–1999 Factory-verified

GM factory document — 1998 buick riviera rpo code list, p.1.
GM factory document — 1999 buick riviera rpo code list, p.1.

Skylark — N-body (1992–1998)

1998 Factory-verified

shared N-body code; Chevrolet Malibu kit.

GM factory document — 1998 buick skylark rpo code list, p.1.
GM Heritage factory kit — 1998 Chevrolet Malibu, p.6.

Terraza — U-body / GMT201 (2005–2007)

2005–2007 Factory-verified

GM factory document — 2005 buick terraza rpo code list, p.1.
GM factory document — 2006 buick terraza rpo code list, p.1.
GM factory document — 2007 buick terraza rpo code list, p.1.

Verano — Delta II (2012–2017)

2016 Factory-verified

2016: all trims: O

GM factory document — 2016 buick verano fleet order guide wayback, p.4.

This page aggregates every documented appearance of K05 in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.