1997 Hummer Model Year Changes.

There were significant changes for the 1997 model year. All 1997 models came with a sound proofing package that reduced interior noise significantly, and turbo diesel engine changes that increased power 5 hp and 45 lb.ft. torque over the previous years model. The power increases on the turbo are enough that they are noticeable. Power output for the Turbo model Hummers remained consistent from '97 through the 2003 model year. The N/A Diesel was still available in '97 but the Gas engine was not available after the 1996 model year. Along with improved ventilation, the 1997 model also offered optional heated windshields to combat windshield frosting which can be a problem on earlier models. Mid year changes were significant enough that the later 1997 Hummers are referred to as "1997.5" models (the factory referred to them as 1997-2 models). The first "1997.5" has a Vehicle Identification Number (VIN) of VE176477 (last 8 digits). Changes for 1997.5 included a much improved HVAC system that was both much more efficient and easier to service and the new Monsoon stereo system with overhead console. 1997 and especially 1997.5 models have many features and refinements which make them favorite years for many Hummer enthusiasts.

Powertrain and Identification Information. VIN 10th Digit designating year = "V" Engine: 6.5L Diesel 170 H.P. 290 lb. ft. VIN 4th digit ="Y" 129 produced. Optional Engine: 6.5L Turbo Diesel 195 H.P. 430 lb. ft. VIN 4th digit ="Z" 1,080 Produced. 4L80E Electronic 4 speed Automatic Transmission. VIN 5th digit ="A" Top Speed 83+ mph with Turbo. 1st "1997.5" VIN VE176477. 1209 '97 models built.

Significant changes for 1997. Increased horsepower and torque on Turbo Diesel engine. Compression ratio went from 21.5:1 in 1996 to 20.2:1 in 1997. Engine also now features an oil spray piston cooling system. For 1997 both turbo and non-turbo diesel models are equipped with integrated power steering pump and reservoir. Complete redesign of the exhaust system from the crossover pipe to the tailpipe. The new design incorporates a one-piece heatshield with added stiffeners to reduce exhaust resonance. Heavy Duty rear bumper standard. Black High Gloss Wheels. Black Grille with High Gloss Black Underbody and Bumpers. Different Seat Fabric and sew style pattern. All seat adjustments moved to front of seat (some adjustments moved back to sides on later model years). Low coolant and glow plug monitoring lights added on dash. Sliding rear window on HMC4 and XLC2 now standard. Deluxe Interior now standard. Air intake Scoop for improved ventilation . New Rear Scupper valves improve ventilation. All vehicles meet new high speed fuel filling (CARB) requirement. New style water crossover for non-turbo engine. Additional bleeder valves added to radiator where overflow hose attaches to radiator. Surge tank redesigned. Shroud-mounted style power steering oil cooler now on non-turbo diesels also. Turbos and non-turbos now have common accessory drives. Heated Windshield option. "6.5L Turbo" badges added on turbo models. Shifter boot cover for increased boot protection and reduced heat and noise. New Color Fly Yellow (only year for Fly Yellow, slightly darker "Competition Yellow" '98 on) Tan and Blue Metallic dropped for '97. VLCO Half Door Open Top and VLC2 2-Passenger regular cab no longer available. HVAC Changes 1997. Newly designed auxiliary unit with angle-mounted louvers. Same compressor on turbo and non-turbo diesels. Improved air ducting. Blower motor revision to push rather than pull heat and A/C through HVAC system. Revised close-out dash panels to provide more air distribution to the floor vents. Additional changes for '97.5 Enhanced HVAC system with increased efficiency and easier serviceability (in addition to changes listed for 1997 above). Monsoon radio available with overhead console.

Change illustrations:

Valuable upgrades to look for in a '97. '97.5 Style HVAC system. About a $4,500 to $5,000 upgrade. Much improved Heating and cooling and new unit is more easily repaired than earlier sealed units. Make sure heater core is not leaking on non-upgraded HVACs. Expensive upgrade to '97.5 specs is factory recommended solution to this problem. Although steering components were upgraded several times by '97, the factory "Problem Solver" Idler and Pitman arms introduced in later years are much more durable than those on a '97. Small rubber plug in Transfercase sometimes shrank due to heat and fell out, slowly draining Transfercase. Later designs solved this problem. Some owners tapped the hole and replaced the rubber plug with a metal one. There was a recall on some '97 models that replaced this plug. Enhanced engine block- Turbo Diesel Engines with block castings before May 1999 are susceptible to #8 cylinder cracks. Most frequently the first symptom of a cylinder crack is coolant being forced out of the cooling system causing the "check coolant" light to illuminate. Many engines have been replaced with blocks of the same design. Even though the enhanced blocks were first produced in May 1999 it took some time before they made their way through the system and into Hummers as either original equipment or for replacement. Even Hummers produced in 2000 are likely to have the pre-May 1999 block casting. There is a casting number on the right rear of the block under the cylinder head which should be E_99 (May 1999) or later. Unfortunately the codes changed through the years so identifying the enhanced blocks is even more difficult. Later blocks also use metric bolts to attach the bell housing but it is unclear whether this clearly identifies an enhanced block. Although enhanced blocks were installed in Hummers produced before the engine manufacturer change to General Engine Products (GEP), the easiest way to make sure a Hummer left the factory with an enhanced block is to check the 4th digit of the VIN on 2001 and later 6.5L turbo diesels. If the 4th digit is an "F" the engine was produced by GEP and is sure to have the enhanced block from the factory.

'97 Specifications, options & Prices:

Available colors:

Red. (R7)

Fly Yellow (Y18) (new for '97). '97 only year for Fly Yellow

White. (W8)

Burgundy Metallic. (P17)

Bright White. (W14)

Green Metallic. (G10)

Black. (B9)

Silver Metallic. (S15)

Although most factory custom colors show up on emergency vehicles and as factory tests, custom colors were available on all Hummers for an additional $1,000 charge. Below is an example of a '97 with a factory experimental color. Pictured is the only Cactus Green Hummer produced in 1997. Cactus Green was an experimental color that never made it into full production.

Body Styles Available in '97:

HMC4. 4-Passenger Hard Top. VIN 6th & 7th Digits "83"

HMCS. 4-Passenger Wagon. VIN 6th & 7th Digits "84"

XLC2. 2-Passenger Hard Top Enlarged Cab. VIN 6th & 7th Digits "89"

HMCO. 4-Passenger Full Door Open Top. VIN 6th & 7th Digits "90"

TOTAL PRODUCTION COUNT BY MODEL AND COLOR. "X" Colors are "Experimental" or special order, often seen as production colors in later years.

COLOR FULL DOOR OPEN TOP (HMCO) WAGON (HMCS) HARD TOP (HMC4) 2-PASS. ENLARGED CAB (XLC2) TOTAL B9 (Gloss Black) 43 154 56 30 283 G10 (Gloss Green) 34 105 35 23 197 G5 (Flat Green) 2 2 P17 (Burgandy Metallic) 9 16 10 35 R7 (Gloss Red) 34 53 42 23 152 S15 (Silver) 20 79 27 2 128 T11 (Gloss Tan) 1 1 W14 (Bright White) 23 102 47 17 189 W8 (Gloss White) 31 32 24 3 90 Y18 (Fly Yellow) 49 37 23 11 120 X02 (Safety Green) 1 3 4 X13 (Bright Green) 1 1 2 X14 (Dark Red) 1 1 X15 (Candy Apple Red) 2 1 3 X16 (Cactus Green) 1 1 X17 (Smokey Carmel (Mesa Dusk)) 1 1 Tan Interior 123 255 116 494 Gray Interior 122 325 153 115 715 Cloth 216 537 245 55 1053 Vinyl 29 43 24 60 156 Deluxe Trim 245 580 269 100 1194 Fleet Trim 15 15 Turbo Diesel 186 484 187 60 917 Turbo Diesel (CA) 35 86 35 7 163 NA Diesel 24 10 47 48 129 TOTAL 245 580 269 115 1209

© Copyright 2004 Jim Lynch