Yukon stored for 10 years. How to bring back to life?

[tomloans]

You're definitely correct on draining the gas. Probably siphon tbh. If there's any solidified / preciptated schmoo, no point in having it go through the fuel pump. If you feel comfortable doing so, pulling the fuel tank down would probably be the easiest.

Could also replace the fuel filter. '01 should have an external unit attached to the frame rail roughly under the driver's seat.

Yes on battery

Other things, in addition to what's been posted above:

- Inspect belts, pulleys, any rotating bits. Belts aren't made from rubber any more, so while you may not need to replace them - you should inspect them and spin any accessories by hand. If the alternator feels a bit crusty, it should clear up shortly - brushes / contacts will self-clean when it spins

- Check wheel bearings, brakes

- Flush brake fluid (takes about 2 liters)

- Should just give all the fluids a once-over tbh. At a minimum, replace coolant and engine oil. Rationale being that engine oil is exposed to moisture. And coolant will degrade even if ya never start the engine

- Like Ratled suggested, pull the plugs and put some oil in the cylinders. Doesnt have to be MMO. Just a little squirt of anything. Then, while you have the plugs removed, turn the engine over a couple times by hand. Make sure nothing is binding. Honestly it may not be a bad idea to add ~10oz of 2 stroke oil to the first fill of the tank. It'll give some lubrication to all the parts and ease their transition back into service. It also makes a pretty decent cleaner. Use TCW marine rated stuff - it's ashless and safe for catalytic converters / sensors (I actually run it in my own rig on the daily @500:1, don't judge me)

- a/c will probably need an evac+recharge

- Go through all soft + rotating parts with scrutiny

- Tires are toast. Replace them. They might hold air, but the rubber is going to be degraded and unsuitable for safe-use

- Pull the air filter out, look under any electrical covers - really any place you can think of that rodents would hide

- When you add new gas, use premium (octane ratings degrade in storage) and toss a bottle or 2 of techron in there (I'm sure other stuff would work but that's the only thing I can speak on as I've personally validated it to actually clean)

- Realize that after sitting that long, and if everything checks out, it'll probably run a little funny as the computers re-calibrate from scratch and everything settles into place

- Also realize that even though it's only 40k miles, soft parts like gaskets will have degraded from age. And particularly any spinny bits - they might start leaking once put back into service. Just keep an eye on them


- One last note about fluids - after you drive it around the block, you'll want to check levels once again as air will bleed its way out. Trans fluid in particular - check it after idling for a minute or two. If you see air bubbles / foam on the dipstick, turn it off, let the air settle out of the system, then start again and check level.

Ditto! Tires will be shot. Don't take this lightly Do not use them. Replace! You will not be able to judge the tires by appearance only.

Definitely some gas cleaner in your tank. I use seafoam but everyone's has their preference.

If it were me, I would change the engine oil/filter and transmission oil/filter before first start.
( Unbolt the exhaust at the manifold on both sides before you attempt this - don't unbolt the the tranny pan until you are successful with the exhaust bolts - pan will not come off without dropping the exhaust a bit ) Then after warm up, maybe drive around the block once or twice. Then I would change the oil again! Also, it may have never had a differential oil change front or back and likely the transfer case has never been touched. I would change these out as well. The hardest part is the rear differential as it requires the back plate to be removed for draining and new gasket thereafter. Just do these as well before first start if you can. Easy peasy.

I would spray all rubber parts like all suspension bushing with ATP AT-205...

https://www.amazon.com/gp/product/B000NVW1LM/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I put it in a spray bottle for the external rubber parts. You can also pour it in your oils (FOLLOW THE DIRECTIONS). It is super expensive but really works to help rejuvenate seals. It has saved me over time. Recently on a hydraulic power trim and tilt system on my boat. The leak is gone! The seal is working again. It is a wonder product really. At least it is for me.

The engine, transmission, transfer case, both differentials are all so very important. Oil is cheap. Change them out. Twice with the engine and transmission after the first few miles on the new oil. ( you could likely just drain and fill the tranny on the 2nd oil change so it will be easier - probably don't need to drop the pan again)

Once you protect the costlier items as noted here, the rest will pop up and will be easy fixes.

 

[rockola1971]

You're definitely correct on draining the gas. Probably siphon tbh. If there's any solidified / preciptated schmoo, no point in having it go through the fuel pump. If you feel comfortable doing so, pulling the fuel tank down would probably be the easiest.

Could also replace the fuel filter. '01 should have an external unit attached to the frame rail roughly under the driver's seat.

Yes on battery

Other things, in addition to what's been posted above:

- Inspect belts, pulleys, any rotating bits. Belts aren't made from rubber any more, so while you may not need to replace them - you should inspect them and spin any accessories by hand. If the alternator feels a bit crusty, it should clear up shortly - brushes / contacts will self-clean when it spins

- Check wheel bearings, brakes

- Flush brake fluid (takes about 2 liters)

- Should just give all the fluids a once-over tbh. At a minimum, replace coolant and engine oil. Rationale being that engine oil is exposed to moisture. And coolant will degrade even if ya never start the engine

- Like Ratled suggested, pull the plugs and put some oil in the cylinders. Doesnt have to be MMO. Just a little squirt of anything. Then, while you have the plugs removed, turn the engine over a couple times by hand. Make sure nothing is binding. Honestly it may not be a bad idea to add ~10oz of 2 stroke oil to the first fill of the tank. It'll give some lubrication to all the parts and ease their transition back into service. It also makes a pretty decent cleaner. Use TCW marine rated stuff - it's ashless and safe for catalytic converters / sensors (I actually run it in my own rig on the daily @500:1, don't judge me)

- a/c will probably need an evac+recharge

- Go through all soft + rotating parts with scrutiny

- Tires are toast. Replace them. They might hold air, but the rubber is going to be degraded and unsuitable for safe-use

- Pull the air filter out, look under any electrical covers - really any place you can think of that rodents would hide

- When you add new gas, use premium (octane ratings degrade in storage) and toss a bottle or 2 of techron in there (I'm sure other stuff would work but that's the only thing I can speak on as I've personally validated it to actually clean)

- Realize that after sitting that long, and if everything checks out, it'll probably run a little funny as the computers re-calibrate from scratch and everything settles into place

- Also realize that even though it's only 40k miles, soft parts like gaskets will have degraded from age. And particularly any spinny bits - they might start leaking once put back into service. Just keep an eye on them


- One last note about fluids - after you drive it around the block, you'll want to check levels once again as air will bleed its way out. Trans fluid in particular - check it after idling for a minute or two. If you see air bubbles / foam on the dipstick, turn it off, let the air settle out of the system, then start again and check level.

I dont understand why you believe the AC has to be evac and recharged? Refrigerant and the PAG oil doesnt go bad or stale. If the system developed a leak over the 10 years of sitting then of course it would need a evac/leak fixed/evac/recharge but if it hasnt leaked out a substantial amount of refrigerant then topped off and tighten valve cores for low and high side and should be good to go.

I definitely would NOT attempt to use 10 year old tires no matter how good they "look". Guaranteed those are dry rotted and cracked in the tread and sidewalls.

I would watch the front transmission seal for leaks, rear Tcase at the driveshaft, Pinion seal, rear and front main seal of engine and plan on atleast one of them leaking.

 

[tomloans]

AC is overboard with respect. If it doesn't work you can always get to it when you can. Main items is the big ticket items as noted above. Best wishes!

 

[SnowDrifter]

I dont understand why you believe the AC has to be evac and recharged? Refrigerant and the PAG oil doesnt go bad or stale. If the system developed a leak over the 10 years of sitting then of course it would need a evac/leak fixed/evac/recharge but if it hasnt leaked out a substantial amount of refrigerant then topped off and tighten valve cores for low and high side and should be good to go.

I definitely would NOT attempt to use 10 year old tires no matter how good they "look". Guaranteed those are dry rotted and cracked in the tread and sidewalls.

I would watch the front transmission seal for leaks, rear Tcase at the driveshaft, Pinion seal, rear and front main seal of engine and plan on atleast one of them leaking.

Interstices

a/c will lose just a bit per year through the seals, even though there's no leak. Sort of like how a balloon will deflate

If it's 22 years old, an evac/recharge will validate the seals and ensure that it's at a proper fill

 

[tomloans]

Interstices

a/c will lose just a bit per year through the seals, even though there's no leak. Sort of like how a balloon will deflate

If it's 22 years old, an evac/recharge will validate the seals and ensure that it's at a proper fill

Got it and it makes sense.

 

[rockola1971]

Interstices

a/c will lose just a bit per year through the seals, even though there's no leak. Sort of like how a balloon will deflate

If it's 22 years old, an evac/recharge will validate the seals and ensure that it's at a proper fill

The leaks at the seals are caused by no PAG oil being circulated through the system during off season nonuse. 10years would definitely cause a fair amount of refrigerant loss...maybe. I would be more worried about corrosion to the evaporator and condenser especially if stored outside or worse sitting in weeds. If the system still has a fair amount of pressure then Id top it off to 40PSI or so and run it then if after a week or so its still good do a final charge. Dischargingrefrigerant to the atmosphere because "you" dont own a evacuation unit is reckless.

 

[SnowDrifter]

The leaks at the seals are caused by no PAG oil being circulated through the system during off season nonuse. 10years would definitely cause a fair amount of refrigerant loss...maybe. I would be more worried about corrosion to the evaporator and condenser especially if stored outside or worse sitting in weeds. If the system still has a fair amount of pressure then Id top it off to 40PSI or so and run it then if after a week or so its still good do a final charge. Dischargingrefrigerant to the atmosphere because "you" dont own a evacuation unit is reckless.

I'm going to be that guy for a sec

Please don't arbitrarily top it off

Refrigerant in the system is a mix of liquid and gas, the pressures of which are very temperature dependent

The boiling point might be 40psi at 45 degrees. If it's 90 degrees out, that changes to 105psi

An under-charged system won't do much other than perform poorly. Over-charged, however, will cause some issues. At a minimum, it'll actually perform worse because it'll drop the compressor duty cycle on account of the pressure in the system being too high. And at worst - you can end up with liquid in your low pressure side and hydrolock (break) your compressor.


And add to that: the vast majority of r134a cans sold OTC have stop leak in them, which is a big nono. It gums up the system. Like, literally, gums it up. If you take it apart - it looks like there are strings of chewing gum in it. Stuff's nasty. Can't really clean it out either. It gets expensive quick.


If you have an actual pressure gauge that'll read low and high side, you can approxamate your fill, but even that has some dependencies on the compressor working well and condenser having good airflow. Ideally, it's done by weight such that any discrepancies in the system can be attributed to other causes and diagnosed accordingly. It's sort of like wondering why your engine is pinging, so you start checking everything, except oops it just had old gas in it and you were chasing your tail. Need to have a solid foundation from which to build on.


evac/recharge around where I am is about 70 bucks. I had it done when I got the vehicle. It's been a while and I don't remember the physical numbers, but I remember doing some mental math that it was about 10% low, and lost about 1% a year.

 

[exp500]

I've done a couple parked it with a fulltank 5-10years ago last couple years. Two kept biting back till I Drained all fuel, added 5 gal gas and a couple cans of berrymans and pumped it in a circle to remove varnish. Tried just draining and refilling with new filter, but varnish flakes came from everywhere until fuel lines cleaned up. Was hell on the holley equipped one!

 

[rockola1971]

I'm going to be that guy for a sec

Please don't arbitrarily top it off

Refrigerant in the system is a mix of liquid and gas, the pressures of which are very temperature dependent

The boiling point might be 40psi at 45 degrees. If it's 90 degrees out, that changes to 105psi

An under-charged system won't do much other than perform poorly. Over-charged, however, will cause some issues. At a minimum, it'll actually perform worse because it'll drop the compressor duty cycle on account of the pressure in the system being too high. And at worst - you can end up with liquid in your low pressure side and hydrolock (break) your compressor.


And add to that: the vast majority of r134a cans sold OTC have stop leak in them, which is a big nono. It gums up the system. Like, literally, gums it up. If you take it apart - it looks like there are strings of chewing gum in it. Stuff's nasty. Can't really clean it out either. It gets expensive quick.


If you have an actual pressure gauge that'll read low and high side, you can approxamate your fill, but even that has some dependencies on the compressor working well and condenser having good airflow. Ideally, it's done by weight such that any discrepancies in the system can be attributed to other causes and diagnosed accordingly. It's sort of like wondering why your engine is pinging, so you start checking everything, except oops it just had old gas in it and you were chasing your tail. Need to have a solid foundation from which to build on.


evac/recharge around where I am is about 70 bucks. I had it done when I got the vehicle. It's been a while and I don't remember the physical numbers, but I remember doing some mental math that it was about 10% low, and lost about 1% a year.

I agree partially. Just dumping refrigerant in the system without even checking the pressure it is at will cause more problems. Thats why I said to charge it to 40PSI (which means run the ac at max to get an accurate reading for atleast 10mins.) You will not ever see 105 psi on a automotive ac system on the low side unless its grossly overcharged or there is a severe restriction. Normal operation would never yield 105psi on the low side, not even at 90deg ambient temp. "You" truly dont even need to hook up to the high side except to diagonose a problem. I almost never need to hook up to the high side while charging auto.....because ive done it so many times. The refrigerant pressure is indeed dependent strictly on temperature. As temps go up, the pressure goes up and vice versa. The 40PSI charge target I mentioned has been adjusted to current outside temps which will work for most areas right now unless you live in the tropics.
Good point: Never buy refrigerant with stop leak in it. The white cans almost always never have stop leak in them. I charge from a cylinder because I buy my refrigerant in bulk.

 

[Doubeleive]

Geez you guys are WAY over complicating and over analyzing this. The ac system is sealed, leave it be unless it doesn't work