Thanks guys for the replys, just got back from work. I definitely intended on draining, but wasn't real sure on the process. I've always wondered why the whole tank doesn't drain out when we pull the HFCM plug to drain water out. Apparently, the pump needs to pull it. We must have a check valve between tank and HFCM? So the Blower technique is to open this check? I just knew that one day it would happen to me. I made it almost 8yrs. without this Bozo move.
This is definitely GREAT info that needs to be published in a more public place. I have feared this before, and I absolutely NEVER let anyone else drive my truck for fear they'll accidentally do the same thing.
I know 2 people who did this and because they didn't know, they both trucks ended up in "totaled" condition. OUCH.
Remove HFCM drain plug, Use shop rag around compressed air blow gun, carefully pressurize tank (doesn't take a lot) Push it out. Refill with diesel. Done.
you would be surprised how little pressure it takes to expand a tank ,,I was pressure testing my new one and even 5 psi was seemed to stress the tank ,,
however I had all the vent's blocked .. not sure if you will get much psi to build with the factory vent and overflow open? .. but I am sure it will get it drained
If you figure out the surface area of your tank , in square inches, and multiply that by the pressure you put into the tank, say 5 psi, you will be astounded at the force applied to the tank. Assuming that the tank is 48 inches, by 18 inches, by 18 inches (which it is not) that gives you something like 77,000 pounds of force on the tank!