If I put much more than 20 gallons in the tank(s) it starts leaking. Doing a little research shows that this truck actually has 2 tanks. Is fuel pumped between the tanks or is one tank higher than the other? Thinking if that is the case I would be able to narrow down possible leak sites. How dificult is it to R&R these tanks?

Thanks,

Kirk

 

How do you know it isnt leaking from either a seam in one tank or usually from the grommet in the filler neck?

 

I am just starting to diagnose this, haven't even had a chance to crawl under the truck to see what there is to see. Just wondering if the fact that anything more than 20 gallons starts leaking gives me any clue as to how to proceed.

Thanks for Reading,

Kirk

 

wait. what? 2 tanks?

 

Yea, I dont think it has 2 tanks. I think there are 2 tanks available one standard like in mine, the 33 gallon tank is standard and the 42 gallon is optional. But you dont have both on the same car.

Is it easy to do? No, because in my car the spare is inside the car the tank is behind the axle. In your car the spare tire is behind the axle so the tank is OVER the axle and exhaust system.

I still think the grommet which connects the filler neck to the tank has deteriorated and the tank is solid. So when the tank is more than 1/2 full it starts to leak. When you put the tank where it is it almost never rusts out because it is hidden from the elements.

 

Yes, and at what level does it hold without dropping? It could be sloshing while driving if you don't see anything on the driveway. If it's a leak underneath the tank (on bottom) you'll need to replace it, in the meantime take a bar of soap rub it on the leaking area, temp fix. Unless it was some sorta special order it won't have two tanks, if it did, you would have a tank transfer switch in the cab.

 

Have done a little research on Alldata and the 2500's with a 38 gallon tank have two interconnected tanks. They are called front and rear, function as if there is only a single tank so no switching between them. If I follow it correctly fill tube goes to rear tank and there is a transfer system to move it to the front tank and then pumped to pressure for engine. Been raining here for a week so still have not crawled under to see what there is to see, but hoping the transfer tube is leaking and not the tanks. Each tank is about $850, but am pretty sure I would not need both since it is only happening when I put more than ~20 gallons into it. Course that means more frequent stops at the station.

Thanks for the discussion so far,

Kirk

 

go to lmctruck.com and see what they want for a replacement tank.

 

Did you ever get this figured out? We have a 2001 Chevy Suburban 2500 with about 186,000 miles on it (we bought it with 22,000 miles and have had it 21 years!!) and it does indeed have two tanks. We are having an issue with the gas line between the two tanks. My understanding of our problem is that where the gas line goes in the front tank from the rear tank, that somehow (I have no idea how it would have happened) the tip that the gas line goes into to get the gas into the tank from the back tank, broke off. The line is hanging on by a lick and a promise from what I understand. Short of buying a new front tank, is there a way to re-route a line to use just the rear tank? Is there a reason we couldn't do that? My grandson drives and loves this truck and doesn't have a whole lot of money to fix it up. The gas gauge doesn't always work, but if it did, would it make a difference in the accuracy if he only used the rear tank? It seems to me like it would not read right if both tanks aren't used.