Engine Oil Additives/Engine Oil Flushes
Do not add anything to the oil. The recommended oils with the dexos specification and displaying the dexos certification mark are all that is needed for good performance and engine protection.
Engine oil system flushes are not recommended and could cause engine damage not covered by the vehicle warranty.
See also:
Sheet Metal Damage
If the vehicle is damaged and requires sheet metal repair or replacement, make sure the body repair shop applies anti-corrosion material to parts repaired or replaced to restore corrosion protection.
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Confident and agile driving experience
Two new engines are offered on all GMC Terrain models, each with fuel-saving
direct injection and variable valve timing technology. Vehicle highlights
include:
New 3.0L DOHC direct injected V-6 ...
Underbody Maintenance
Use plain water to flush dirt and debris from the vehicle's underbody.
Your dealer or an underbody car washing system can do this. If not removed, rust and corrosion can develop. ...