Dual Tanks
 

My 86 Silverado has the dual tank options. I had it now about 7 years. Question is I never used the other tank. I'm scared that the other tank gas in it may be bad and if I switch over it may mess up my engine. Looking for some advice on the best way to approach this. Thanks ahead of time.

Re: Dual Tanks
 

if its been 7 years, personally, I would just replace it with a new one....a new one can be had for around $100 or so, cheap piece of mind....however, I guess my way of thinking also creates a bit of a domino effect, because you would probably, logically, want to put a new sending unit in there also, so theres another additional $40-$50, still cheaper that running bad gas through the carb and all

Re: Dual Tanks
 

That's what I would do! If your going to start using it, just buy new stuff. Check you switching valve also. That is expensive to replace, so check that first. If you need a switch valve, you might be able to find one used on this forum. I know I have 2 extra's.

Re: Dual Tanks
 

That gas tank needs new rubber fuel line hoses anyway. Drop it and inspect. If the insides are good, replace hoses and put back in service. If the insides are full of rust and gas varnish, buy a new tank and sender. While it is off, inspect the filler hose and replace if needed. Inspect the brackets and straps and replace if needed.

You have gone 7 years without using the 2nd tank. Having it off a few weeks if you need to order new shouldn't be too much of a problem.

Re: Dual Tanks
 

Thanks you guys

Re: Dual Tanks
 

I'm thinking about replacing the tanks also. My truck has been sitting for a couple of years on the one tank, and longer on the other tank.

What else would I need along with the tanks and sending units? While I'm replacing, I want to make sure I get everything covered.

Classic Industries has 40% off this weekend.

Re: Dual Tanks
 

Without inspecting, hard to say. After reading about horror stories of rust both inside and out on tanks with the plastic guards on them, I dropped the passenger side tank on my 75 to inspect a few years ago. It only had a few spots of rust on the inside, a couple of spots on the outside under the plastic, and the filler hose was in good shape. The fuel line hoses did need replacing. The support brackets and straps were also in good shape. Wound up repainting everything and putting the tank back in service with new fuel hoses.

Probably should have replaced the ground wire. About a year ago, I started getting an intermittent 3 o'clock fuel reading on that side.

If you know you need senders, make sure they include new gaskets. New ground wire. New fuel line hoses. If you don't have a charcoal canister, new vent caps. Look at your filler hoses. Easier to replace while the tank is on the ground.

If your support brackets look good, might order new straps anyway if they don't cost a lot. Hard to inspect the straps without dropping the tanks.

You need a plan to get rid of all that old gas. I just ran that side dry before dropping it. Still had about a gallon in it.

Re: Dual Tanks
 

Thanks for the response. Is there a specific brand or place to purchase the tanks & senders? Yeah I need a plan on the disposal of the gas alright. The right side is the oldest gas and probably the fullest.

Another question on the senders? I was looking at a few places and seen where they say 2 outlets or 3 outlets. What would I need? 86 C10 Silverado SWD

Re: Dual Tanks
 

Don't really know on senders. Reused my old one. My 75 had a 2 outlet sender. One to the tank selector valve and one to the short vent hose. Mine was a HD non emission truck so no canister and it didn't have a return from the fuel pump. Guessing that if you have a canister and return from fuel pump, you would need 3 outlets. On mine, if you look just right, you can see the sender top through the cab-bed gap.

Oddly, I use my truck as the way to get rid of my suspect gas. It doesn't seem to care. If I add a lot, I try to top off with fresh gas before switching to that tank.

Re: Dual Tanks
 

In my experience, most old tanks I pull that still have gas in them were still good on the inside. If it were me, I would start by pulling the old gas out, and I'd make a determination from that.

I'd get a small 12v fuel pump (I've seen them under $20 on amazon), but make sure you put a fuel filter inline BEFORE the pump. I like the large, clear ones with a paper element, so I can see any garbage in there. I also like to use LONG wire leads to power my pump, reduce the risk of arcing causing a fire by moving my power source far away. A cheap roll of speaker wire works great, 18 gauge is probably plenty big enough.

If the fuel filter is clean after you pull all the gas, I'd maybe just fill it and try it. You might even find a way to keep the fuel filter inline there, as an added measure of security and inspection later on.

If the fuel filter is dirty and clogged, you definitely need to pull the tank, and now it's easier because it's empty!

Re: Dual Tanks
 

Thanks for the advise, I was trying to determine a way go pumping the gas out of the tanks.

Is there a screen or anything that would keep the hose from reaching the tank?

I did try and use a hand pump, that I have on my gas can for the lawn mower. It makes filling the lawnmower easier than lifting a 5 gallon can when it's full. It could have been because the hose was too big once it reached the tank entrance. I didn't want to force.

Re: Dual Tanks
 

I'm glad to see some guys posting here with some logic. I can't imagine just buying a new tank because the one you have hasn't been used in a while. You guys much just have too much money.

Take a little time and follow what Wilkin has recommended.

Re: Dual Tanks
 

I plan on it, following what Wilkin recommended. I'm looking at fuel pumps now on Amazon. I really didn't want to spend the money, unless I have to, or even get into that kind of work. :metal:

Re: Dual Tanks
 

There shouldn't be anything inside the tank to prevent a hose from getting down in. It's not like these new vehicles and their anti-siphon devices. These are old trucks, you should be able to push a small fuel line down. I wouldn't worry about forcing, it's a rubber hose, not a metal rod. I don't even think you CAN push a rubber hose with enough force to damage anything. The rubber will give out before anything else will.


But if it were me, I'd probably go straight to the source. I'd crawl underneath and pull the fuel line off the switching valve, and connect an extension with my fuel filter and electric pump. I'd want to see the fuel exactly the same way it would be delivered. If there is corrosion or clogging at the sending unit itself, you won't see it if you pull the fuel from the filler neck.

Then again, it's easy for me to crawl under mine because my fuel lines are 4ft off the ground. I might think differently if it were more difficult...