Check Oil Level 2026 GMC Sierra 3500 HD SLE 6.6L V8 Turbo Diesel

Checking the oil in a Sierra 3500 HD is fairly easy and should be done once a month. Note that most GMC have an oil pressure gauge next to the speedometer - this gauge does not tell you what your oil level is, but rather uses an oil sensor to indicate the oil pressure in the engine. If you have an oil light illuminate in your Sierra 3500 HD, this means your oil pressure is either high or low. The video above will show you how to check the oil level in your 2026 GMC Sierra 3500 HD by taking an accurate dipstick reading. Make sure your engine is cold when you check the oil in your Sierra 3500 HD. Otherwise the dipstick will read slightly low. In addition to checking the oil level, you also want to look at the condition of the oil when you have the dipstick out. If the oil in your Sierra 3500 HD is dirty or smells like gasoline, you probably need an oil change.

If you notice that the oil level in your Sierra 3500 HD is extremely low or empty, fill it up and check it again the next time you drive. If it is extremely low again, have your mechanic take a look before driving it much more.