GMC Sierra Denali 2008 Owner's Manual
![GMC Sierra Denali 2008 manual cover](/images/lhMTGjQBFlUjZVHBIAWROLxO/thumbs/thumb175x175.webp)
To reset the oil life monitor, turn the ignition to the "ON" position without starting the engine. Press the accelerator pedal three times within five seconds. The oil life will reset to 100%, and the "Change Engine Oil Soon" message will disappear.
The 2008 GMC Sierra Denali typically requires SAE 5W-30 engine oil. It is recommended to use oil that meets GM Standard GM6094M for optimal performance.
To troubleshoot the check engine light, use an OBD-II scanner to read the diagnostic trouble codes (DTCs). These codes will help identify the specific issue. Common causes include a loose gas cap, faulty oxygen sensors, or spark plug problems.
The recommended tire pressure for the 2008 GMC Sierra Denali is typically 35 PSI for both front and rear tires. Always check the owner’s manual or the tire placard located on the driver's side door jamb for exact specifications.
To replace a headlight bulb, open the hood and locate the back of the headlight assembly. Remove the dust cover, disconnect the wiring harness, and twist the bulb counterclockwise to remove it. Insert the new bulb, reconnect the harness, and replace the dust cover.
The 2008 GMC Sierra Denali has a towing capacity of up to 8,700 pounds, depending on the specific configuration and equipment. Always refer to the owner’s manual for precise towing guidelines.
To check the transmission fluid, start the engine and let it reach normal operating temperature. Park on a level surface, shift through each gear, then place in Park. With the engine running, remove the dipstick, wipe it clean, reinsert it, then check the fluid level.
A squeaking noise during braking can be caused by worn brake pads, glazed pads or rotors, or debris caught between the pad and rotor. Inspect the brake components and replace or service as necessary.
Improve fuel efficiency by maintaining proper tire pressure, using recommended engine oil, keeping up with regular maintenance, and avoiding excessive idling. Reducing unnecessary weight and using cruise control on highways can also help.
If the battery light illuminates, it indicates a charging system issue. Check the battery connections, inspect the alternator belt, and test the battery and alternator for proper function. Seek professional help if the issue persists.