GM U-Body 2003 AWD Pontiac Montana Thunder service and maintenance guide by Yuriy Sklyar / San Francisco, California

This article is constantly evolving – check back for updates!

2003 AWD Pontiac Montana Thunder service and maintenance guide

Common issues resolved via text/photo/video; includes links to all required parts. Applies to 1997-2005 Chevrolet Venture, Oldsmobile Silhouette, Pontiac Trans Sport, Opel Sintra, Vauxhall Sintra, and Buick GL8. Enjoy!

A photo of 2003 AWD Pontiac Montana Thunder shown on a screen of a 2016 Razer Blade laptop; next to the computer is one of the heads from the van.

GM 3400 SFI engine rebuild

2003 AWD Pontiac Montana Thunder engine bay

GM 3400 SFI reference shots of a pulled engine... for reference (helped me).

GM 3400 SFI engine main electrical harness and sensors

GM 3400 SFI engine diagram of main components and sensors.

This photo of intake manifold sums up the state in which the engine was. I washed it, cleaned it with a brush in hard-to-reach areas, and painted it using high-heat paints. I chose to stick to 'factory look'.

Pontiac Montana Thunder engine manifold restoration

While cleaning the cylinders/block, be sure not to create scratches. Use a non-metal dish scrub and a degreaser.

Pontiac Montana Thunder engine cleaning the cylinders

Pontiac Montana Thunder engine cleaning the 1, 3, 5 cylinders

Lip upgrade

Upcoming lip design I'm working on will attach to factory bumper with very little work involved. Limited edition run; get in touch to reserve yours.

Pontiac Montana Thunder front lip upgrade featuring slots.

Lights

Convert your lights to LED:

Fog lights
Signals
Reverse
Interior
Brake
Headlights
Resistors (to eliminate hyperflash turning signals)

Pontiac Montana overhead dome LED lights conversion and comparison in brightness and color temperature

Pontiac Montana headlight and turn signal LED lights conversion and comparison in brightness and color temperature

Hypermiling

Current record: 1255km (~780mi) on a single tank from Arizona to California (without cruise control).
Light foot
~44PSI
10-20MPH under speed limit
top-off

About 2003 Pontiac Montana Thunder

I never got into SUVs – they always felt too bulky, while not being overly roomy, so being a father of three, I prefer the #vankulture scene.

This is the most highly optioned minivan of its time:

fully independent (aluminum arms) sports suspension featuring VersaTrack AWD,
on-board computer (outside temp, instant and avg. fuel consuption, distance/fuel estimation & tracking, compass)
special two-tone black/gray leather interior,
heated front seats,
power sliding doors,
backup sensor,
towing package,
roof spoiler,
OnStar,
air compressor + self-adjustable rear air suspension,
custom chrome 5-spoke wheels (235/60/16),
4-wheel disc brakes (others had drums in the back),
110L (27G) fuel tank capable of achieving 1244km (772mi) on single fill-up.

Thunder was a rare package and as a result very few vehicles were produced – especially with this color combination, which makes this one of the most rare vans on the road today.