1998 Lincoln Navigator - fuel issue

[Nav98]

Well, I think I know how bad a situation I’m in but that’s life.

In July of 2024 my wife left our super maintained Nav, less than 40,000 miles, serviced every year at Lincoln, in the garage of our place in Florida. Why? She had been diagnosed with stage 3 cancer and “we,” the family, felt it best to come out to Colorado where a great hospital in Denver developed her plan and she thereafter for a year had chemo, a surgery, and more chemo. I will say she agreed as treatment there was a horror and she was ready to bail on Florida.

How is this relevant to the forum? Well, while she can’t remember how much fuel was in the tank, and we even used 91 octane for years only because we really loved this car. Unnecessary, I know. My wife is fine now, thank God, but I will be going back there for the first time since she was there: 15 months with gas sitting in that fuel tank, amount unknown.

The big question for the forum is, I’m pretty sure I need to drain the fuel from the tank as best I can but there will probably be some “junk” in there that we don’t need to get into the fuel system, and what is in the fuel system to the engine is probably dangerous to think it won’t clog up somewhere. I had one friend say, put some stabil on there and try running it. Then I was told to use Sea Foam Motor Treatment. Still, my question is at what stage?

Do the forum members think with whatever fuel is in there, should I add stabil in the tank, try running it, or as I’m thinking drain as much fuel as I can down to about several gallons, and then add what? ….Stabil or Sea Foam? Or neither? The thought of dropping that fuel tank after draining as much as I can is way too much to even think about, but if I get out as much gas s I can (Ace sells pumps that run on 12V? I use one for my snowblower in Colorado) what’s a good route to go? Where I’ll get rid of up to four - five gallon plastic cans full of old unusable fuel is another issue.

Sure would like to see a consensus on here for a solution. I may need a new battery, no problem. I have the ability to fill the tires to their pressure - of course worried the tires will be squirrelly for a while? Or trashed?

Well, thanks folks. This car has been a champ from day one. Four wheel drive on demand……the only problem I ever had was like many I had to change out the air suspension for springs and have to look at that light there.

Thanks,

A sad guy, not my wife’s fault, mine.

 

[Action]

Adding Stabil at this point is like shutting the doors of a barn that all of the animals have left.
Stabil is designed to keep fuel fresh for longer time.
15 months is not that long. I have driven much older vehicles and boats that sat for longer.

What happens to fuel that is stored is the lighter elements of the fuel can evaporate.
In addition, the elements of fuel and additives may settle out and the mixture is no longer mixed.

Good news about the first part, the fuel system is closed. Meaning, if working properly, outside air will not get to the fuel. No outside air contaminates and little to no evaporation.
The second part is very real.

If it were me I would fire it up and take a long trip. Long enough to go through the whole tank. Then change the fuel filter.
Run another tank and change the filter again.
Then after 500 miles change the spark plugs.
Expect the engine to run a lil rough initially. The battery to be dead and the tires to be OK after about 20 miles. Do fill the tires before driving them. And check/top off all fluid levels.

Action

 

[Nav98]

Adding Stabil at this point is like shutting the doors of a barn that all of the animals have left.
Stabil is designed to keep fuel fresh for longer time.
15 months is not that long. I have driven much older vehicles and boats that sat for longer.

What happens to fuel that is stored is the lighter elements of the fuel can evaporate.
In addition, the elements of fuel and additives may settle out and the mixture is no longer mixed.

Good news about the first part, the fuel system is closed. Meaning, if working properly, outside air will not get to the fuel. No outside air contaminates and little to no evaporation.
The second part is very real.

If it were me I would fire it up and take a long trip. Long enough to go through the whole tank. Then change the fuel filter.
Run another tank and change the filter again.
Then after 500 miles change the spark plugs.
Expect the engine to run a lil rough initially. The battery to be dead and the tires to be OK after about 20 miles. Do fill the tires before driving them. And check/top off all fluid levels.

Action

Thanks, that is somewhat reassuring. I had thought the stabil was a waste of time. You don’t suggest that I do pump out some fuel, put in half a tank or at least 5-10 gallons and then add the sea foam treatment? I’m hoping I get there and there’s little fuel that my worst nightmare thought. Hey, thanks for the feedback, I really appreciate you taking the time. A long trip may be impossible. While a friend eyeballed my place there often I never had him try to start the car. What’s more, before I left I didn’t have time to hook up the in-the-box Optima trickle charger. That’s the first thing I’ll do, check the tire pressures, and then turn the key to at least see the fuel level.

 

[driller]

I have on occasion drained fuel that has been sitting a long time. It's surprisingly easy on most Ford/Lincoln/Mercury vehicles from the 80's and 90's and some beyond.

You disconnect the fuel filter like you were going to change it and leave the inlet line connected to it from the tank, just disconnect the discharge side going to the engine compartment. Find a section of rubber fuel hose that fits the nipple of the filter and jam it on the filter. The length should be adequate to exit from the fuel filter and into a suitable five gallon gas can.

Locate the fuel pump relay and pull the relay. Use a short length of 14 gauge or 12 gauge electrical wire and crimp on male spade terminals on each end. Then use the fashioned wire to 'hotwire' the fuel pump to run. The pump will run and pump the old fuel out of the tank into your gas can. When the can is near full, simply disconnect the hotwire and repeat if necessary.

You can refer to your vehicle's wiring diagram for the fuel pump or refer to the generic pic below. Basically you want to jump from pin 30 (12V+ supply) to pin 87 (hi-speed fuel pump circuit). You may or may not need to key the ignition on (depending if pin 30 is hot all the time or not). You could just as easy use a temporary wire direct from the battery positive terminal to pin 87 on the fuel pump relay socket.


When done, change the fuel filter and reconnect the fuel line, plug in the relay, dump in some fresh fuel and you're good to go.

You can find pics from another forum for reference HERE.

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[Action]

Thanks, that is somewhat reassuring. I had thought the stabil was a waste of time. You don’t suggest that I do pump out some fuel, put in half a tank or at least 5-10 gallons and then add the sea foam treatment? I’m hoping I get there and there’s little fuel that my worst nightmare thought. Hey, thanks for the feedback, I really appreciate you taking the time. A long trip may be impossible. While a friend eyeballed my place there often I never had him try to start the car. What’s more, before I left I didn’t have time to hook up the in-the-box Optima trickle charger. That’s the first thing I’ll do, check the tire pressures, and then turn the key to at least see the fuel level.

Stabil is a fuel stabilizer treatment. The fuel has been sitting for a period and now you are going to operate the vehicle. I would rule that out.

Sea Foam is an additive that is meant to clean the fuel and engine. Taken from the manufacturer, It can be used to clean up the carburetor passages, intake valves and other vital components. It’s designed to remove carbon deposits that build up over time. And it has a stabilizer in it. Your Lincoln has NOT been operated for some months. In that time there has been NO carbon deposits or build up in the combustion chamber.

The biggest concern you have expressed is the fuel that has been left in the tank for just under 2 years.
In the world called perfect, gasoline should be used within six months. That is when it is in it's prime to deliver the power when compressed and fired in the combustion chamber.
The outside factors that degrade gasoline are air, water (moisture) and sunlight. One other factor doesn't degrade gasoline however it is harmful is debris.
For fuel systems made in the last couple of decade, the stock system in working conditions IS sealed by law. (EPA) This means there is no sunlight and no moisture access to the tank, In addition the fuel cap (or capless system) when closed correctly and it working correctly only allows vapor to pass outside of the system should a pressure be reached that is dangerous. Otherwise nearly all the time the system does NOT allow any vapor to leave the system and certainly does not allow any air to leak into the system.

If air, water and sunlight cannot get to the gasoline, then the gasoline will not degrade because of those factors. What will happen is the additives and mixture will separate. That separation will cause the fuel to be at less than optimal. Meaning that tank of fuel may not perform as well as a fresh tank.

Will there be sludge and debris in the bottom of the tank? Unlikely.
There is no exposure to the biggest factors that degrade fuel
And it has been sitting in the tank for months not years.

I have classic cars. (Too many if you ask my wife) these can sit for years if not decades. AND they do not have sealed fuel systems.
I have purchased parts cars (donors) that I have pulled the tank to sell the sender and tank, only to discover the inside was nasty. Water or moisture is usually the problem. And that problem comes from an open (vented) system that sat for years. While air blew in and was pushed out. Bringing in moisture. Over decades, that is a problem.

If you really have a concern, it will show up in the fuel filter first. Do buy one or two filters.
Use the first one after the current tank is empty.
Then change the filter again in 500 to 1000 miles.

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