2005 Dmax. 26 gallon Tank. I would like to blame it on my wife, but it was me. I Went to get gas for the lawn mower and pumped 4.9 gallons of unleaded into the truck while talking on the phone.

I did a bit of research and found mixed answers. Some said to add 2-cycle oil, ATF, or BioDiesel??? Which internet poster do you believe?

I sat at the pump and searched the internet for answers and finally said screw it. I topped it off with diesel. I drove home (2 miles) and picked up some DieselKleen (spelling?). Added enough additive for 50 gallons. Then, drove 35 miles with no problems. I kept resetting the MPG calculator and it never dropped below 19, it never shuttered and it never smoked. There was absolutely no indication of anything different.

Topped it off again (1.6 gallons) and plan on doing that a few more times....or I may drain 10 gallons when I get home (I have two 5 gallon cans) and top it off if it acts up at all.

I'll keep you updated, in the event this might help someone....

More then likely you are fine.
If you want to drain it, your not going to hurt anything.
I will say you were smart adding some additive. Gas has no lubrication, so it's worse then adding any type of additive.
Either 2 cycle or additive will work. Me personally I use Opti Lube XPD every tank. Reason being it will also clean the fuel system and injectors. Far as I know 2 cycle oil really doesn't have much for additives, so it's not really going to clean much.

DOnt bother draining it if you have already driven it more than 20 miles. Any damage that is going to be done is already done. All you need is a high lubricity additive now. Drive it and remember not to do it again, thats what I would do.

I got home today and started the truck for a quick trip to make sure everything was still ok and it was a little hesitant to start. It maybe made turned over an extra 0.5 to 1 second longer than normal to start. I drove it to the bank, again hesitant to start.

When I got home, I siphoned 10 gallons of mixed fuel (18% gas) out. I went to crank the truck it would just turn over, not even sputter. The batteries are five years old and it didn't take more than a few quick tries to hear the starter begin to weaken. I put the battery on the charger while I drained the fuel filter and primed it back up a few times.

About 30 minutes later I tried it again. The starter now turns over like a raped ape (on fresh charge) Five seconds of turning over and it fired up.....I then drove and topped it off with 10 gallons of diesel and some diesel kleen. I calculated my current mix at about 11.4% gasoline.

I drove around for 20 minutes to make sure and get the higher gas concentrated fuel cycled through or burned off. I shut it off and it cranked right back up. Tried it again two hours later and it cranked up again. I'm hesitant to make any long trips, but I think it may be best to burn that bad fuel out without shutting the truck off. The truck runs fine once it is started.

I'm thinking maybe when the bad fuel got hot, due to the ambient heat from the engine, it didn't want to fire. I'm not sure if waiting for it to cool off helped or the fresh battery charge helped or what the deal was. I hope all problems are cleared up from here.

Is DieselKleen a high lubricity additive? What damage could be done? Also, do I need to change the fuel filter? Some people said yes and some no....I can't imagine clean gas would clog the filter any more than clean diesel unless it broke a bunch of crud loose.

Thanks all. In hindsight, I should have just drained it there at the pump or called a wrecker. The stress isn't worth it. Plus everything I own now smells like diesel (and gas).

Stanadyn Lubricity Formula will do the best for ya right now. As long as it starts and continues to run you should be fine. Its when the ECM detects too much knock and shuts it dwon after 10 seconds that you should worry. The fact that it starts and runs fine is a good sign.

Thanks for the tip. Where can I pick up Stanadyne locally? Any large retailers carry it?

i read in a diesel service manual that on some diesel you can actually put up to 30% gas without a notable difference in running. Your fine. You would be amazed at what these things will run on.

Thanks for the tip. Where can I pick up Stanadyne locally? Any large retailers carry it?

You can find a dealer at: www.stanadyne.com (http://www.stanadyne.com)

Dude, forget the Stanadyne and all the other "special" lubes our there. Wal Mart TCW-3 2 cycle oil has more lubricity than most of those anyways and it is much cheaper. The best thing you could do would be to put some Bio Diesel in it as far as lubricity properties, but if it hasn't quit running by now, you should be ok. You won't know of any "long term" damage until well, long term! A far as the 2 cycle oil, put in 3 oz. per gallon and call it good. I only use 1 oz. per gallon, but it doesn't have gas running through it either. I would run the higher concentrate for a few tanks and try to keep your injectors and pump from biting it. Just imagine 100 grit sandpaper on your hand...that's about what the injectors go through with pure gasoline. Hope this helps...it can happen to any of us.

ATF is a bad idea, but 2-stroke is good --- unless that causes problems with a Duramax. People used to add gas to the Diesel to keep it from gelling, about 10%, but that was with simpler engines. What does your owners manual say how to keep the fuel from gelling?

The fuel filter shouldn't need to be changed ... but if you change it now, you still have gas in the fuel. Perhaps the gas can dissolve some dirt and thus take it through the filter, and a new filter won't have the dirt in it.

I Have A 2002 Gmc Crew Cab Duramax / Ally 4/4 Short Box And I Got 8 Gallons Of Gas In My Diesel Tank When I Had 3,100 Miles On The Truck . I Thought The World Came To An End . This Old Timer Told Me To Fill The Tank With Diesel And Forget About It .he Said I Would Have A Story To Tell About It Some Day . Well That Was 7 1/2 Years Ago And I'm Telling The Story Now And I Have Over 150,000.0 Miles On The Truck And Haven't Had A Problem Yet . Don't Lose Any Sleep Over Your Mistake It Will Be Ok .:) :d

I'd think you'd be okay and maybe want to keep the boost down. I'd think that too much boost will create cylinder pressures that could cause the gasoline to detonate, no?