Gas in 2020 GMC Sierra 2500HD Diesel

[Laurent Kim]

I made a huge mistake by putting gasoline (87 octane) in my truck.  I had about 3 gallons of diesel left and put 3 gallons of gasoline until I realized my mistake.  The station was about 3/4 miles from home so I drove it home.  No weird noises and I shutdown the engine.  I won't start the engine again for starters, but what should I do at this point?  Since the engine didn't die on me, maybe the engine is not contaminated yet.  Should I have a shop drop the fuel tank, change the fuel filter and bleed the fuel lines?

Please help.

[Pryme]

53 minutes ago, Laurent Kim said:

I made a huge mistake by putting gasoline (87 octane) in my truck.  I had about 3 gallons of diesel left and put 3 gallons of gasoline until I realized my mistake.  The station was about 3/4 miles from home so I drove it home.  No weird noises and I shutdown the engine.  I won't start the engine again for starters, but what should I do at this point?  Since the engine didn't die on me, maybe the engine is not contaminated yet.  Should I have a shop drop the fuel tank, change the fuel filter and bleed the fuel lines?

Please help.

You are certainly best off draining the fuel. Bring to the dealer if you need to but they may make note of it in your record and that could lead to a denied warranty claim in the future if something happens. I’m just thinking out loud here. 
 

I don’t suppose you could run a small 3/8 or 1/4” hose down the filler and use a Mityvac to pull the fuel out? 

[Silverado4x4]

On 9/19/2023 at 4:06 PM, Laurent Kim said:

I made a huge mistake by putting gasoline (87 octane) in my truck.  I had about 3 gallons of diesel left and put 3 gallons of gasoline until I realized my mistake.  The station was about 3/4 miles from home so I drove it home.  No weird noises and I shutdown the engine.  I won't start the engine again for starters, but what should I do at this point?  Since the engine didn't die on me, maybe the engine is not contaminated yet.  Should I have a shop drop the fuel tank, change the fuel filter and bleed the fuel lines?

Please help.

I would not start the truck at all, since you drove the truck home you already contaminated the fuel rails and lift pump in the tank you need to have it towed to a shop and have the tank drained and fuel system flushed. The diesel fuel lubricates the pump and injectors etc, gas will destroy them as they will not be lubricated. If you wouldn't have ran the truck all you would have to do was drain the tank.

Edited September 20, 2023 by Silverado4x4

[KARNUT]

I’m sure Newdude would know for sure with the latest emissions. There was a time when 3 gallons of gas with a full tank of diesel wouldn’t have done anything. I would have moved to the diesel pump and filled her up.

[txab]

6 hours ago, KARNUT said:

I’m sure Newdude would know for sure with the latest emissions. There was a time when 3 gallons of gas with a full tank of diesel wouldn’t have done anything. I would have moved to the diesel pump and filled her up.

I would have done the same. bet there was more than 3 gallons diesel in the tank when added the 3 gas.

[64BAwagon]

If it made it home I would siphon as much out of the tank as possible or suction it through the fuel line and install a new fuel filter. I would then fill the tank with as much  new fuel as you can and add a qt of 2 stroke oil to it. 

No mention of what year it though. Any aftertreatment system wouldnt like the 2 stroke oil though. 

The gasoline will wipe out the lubricity of the fuel but if you get as much out as possible and add the 2 stroke it should be good. 

Edited September 21, 2023 by 64BAwagon