Must read for those of you not driving your car in Winter
#41
Safety Car
My habit for storage is a bit different. In the C6 I care for, it's sometimes stored for 1 to 3 months (different times of the year) when the owner is traveling. When planned storage is approaching, I make sure she runs a bottle of "Techron Concentrate Plus Complete Fuel System Cleaner" (which is identical to the GM fuel system treatment in a GM labeled bottle, available from the dealerships). That "cleaner" includes a "filming agent" which protects the fuel sender stuff from sulfur deposits. We run that in the last full tank before storage, and when the final fill up for storage is made, add a second dose that to a full tank (filled from as close to empty as possible) of ethanol free gasoline. If the storage is going to exceed 6 weeks, Sta-bil is also added to that full tank..
I'm aware of the sulfur deposits issue, but I'm also skeptical that oxidation from air exposure isn't just as bad or worse. I would advise storage with a full tank of properly treated ethanol free fuel, not with 1/4 tank or less. That's always worked for me (in many different vehicles, including other GM vehicles with the same sulfur deposits/fuel sender issue).
I'm aware of the sulfur deposits issue, but I'm also skeptical that oxidation from air exposure isn't just as bad or worse. I would advise storage with a full tank of properly treated ethanol free fuel, not with 1/4 tank or less. That's always worked for me (in many different vehicles, including other GM vehicles with the same sulfur deposits/fuel sender issue).
Last edited by C6_Racer_X; 12-08-2018 at 11:24 AM.
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#42
GM will not comment on this. The sending units are designed for normal usage and under such usage this is a non-issue. If they start adding comments and suggestions to counter a "problem" they open themselves up for liability. Considering the cost of repair, it just makes sense for those who lay up their cars to drop the level. My '14 has been stored with a near-full tank w/o issues, but I also drive it at least once a month unless there is salt on the roads. Maybe the heated garage helps too - I installed radiant heat so its nice an warm at tank level.
#43
Le Mans Master
The Corvette dual-tank design affords an opportunity for an almost perfect science experiment here.
Which sender has more failures after emerging from winter storage? If it's the video is correct, it will be the left sender. That is, if you could graph the sales of fuel level senders to northern states in springtime you should see more lefts than rights.
On the C6, the majority of sender problems reported are on the right side. It's always the right sender. The right one spends most of the time not immersed in gas. In addition, flakey right-side senders tend to work again once immersed - that is, after a fill-up. I know of many owners with that experience, and almost none where it's the other way around.
My own right level sender failed. On examination the contacts appeared dingy. The left sender contacts looked shiny and new. This was after year-round driving and refueling only when empty, not after winter storage. It's possible there are two failure mechanisms here - wear vs contamination. But it's not obvious to me whether contamination is promoted or prevented by fuel immersion.
I'd like to see the tech in the video back-up his advice with evidence. But even if he can, I suggest that it does not generalize to the year-round case. There we have good reason to believe that keeping the tank full will prevent sensor failure.
Which sender has more failures after emerging from winter storage? If it's the video is correct, it will be the left sender. That is, if you could graph the sales of fuel level senders to northern states in springtime you should see more lefts than rights.
On the C6, the majority of sender problems reported are on the right side. It's always the right sender. The right one spends most of the time not immersed in gas. In addition, flakey right-side senders tend to work again once immersed - that is, after a fill-up. I know of many owners with that experience, and almost none where it's the other way around.
My own right level sender failed. On examination the contacts appeared dingy. The left sender contacts looked shiny and new. This was after year-round driving and refueling only when empty, not after winter storage. It's possible there are two failure mechanisms here - wear vs contamination. But it's not obvious to me whether contamination is promoted or prevented by fuel immersion.
I'd like to see the tech in the video back-up his advice with evidence. But even if he can, I suggest that it does not generalize to the year-round case. There we have good reason to believe that keeping the tank full will prevent sensor failure.
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#45
Pro
Have we used "Ask Tadge" for comments from Engineering?
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Maxie2U (12-10-2018)
#46
Put in some Stabil....on a clear day back out of the garage, warm the engine good and back and forth in the driveway a few times to "slosh" the fuel around...
Last edited by 396tears; 12-09-2018 at 10:53 AM.
#49
Le Mans Master
I always stored my C6 Grand Sport with a full tank and Sta-Bil with no issues, and did the same with my new C7 ZO6, so too late this year to try the 1/4 tank idea, but maybe next time I'll try that approach. The whole subject of winter storage is a lot like asking 10 Doctors a question, you will get 10 different answers. Always stored cars with full tank of fuel with no issues, but I'm open to try a new approach, it seems to make sense.
#50
Pro
Now that I know we don't need to worry about condensation, I won't worry about how much gas I have in the tank before I store the car.
When they designed this car, they knew most people stored this car for winter or that it wasn't driven much all year. If this is a problem, why haven't we heard about problems already if this has been used since the C5's?
#51
Team Owner
Member Since: Aug 2007
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St. Jude Donor '11-'12-'13, '16-'17-'18
After giving this more thought, the following occurs to me
The 'vett's fuel system, while being closed, is fuel injected
This means that over-delivered gas to the high pressure pump/injectors is returned to the tank.
That returned gas is warm, certainly warmer than the surrounding air (at least during winter).
Any air that is in the system therefore will condense out as the fuel cools.
I don't buy the author's reasoning
The 'vett's fuel system, while being closed, is fuel injected
This means that over-delivered gas to the high pressure pump/injectors is returned to the tank.
That returned gas is warm, certainly warmer than the surrounding air (at least during winter).
Any air that is in the system therefore will condense out as the fuel cools.
I don't buy the author's reasoning
Last edited by KenHorse; 12-10-2018 at 01:37 AM.
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#52
#53
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So many variables come to mind regarding the vehicle in the video:
- age of the vehicle
- number of miles on the vehicle (average annual mileage, is it a driver or trailer queen)
- number of months of the year the vehicle sits stored
- where does he buy his fuel (Exxon, Shell, 'Bob's Discount Gas Bar', could result in different sulfur levels in the fuel)
- which fuel grade (regular or premium, again depending on the refinery could result in different sulfur levels in the fuel)
- did he use a fuel stabilizer
There are probably other things that should be considered as well before jumping to any major conclusions.
- age of the vehicle
- number of miles on the vehicle (average annual mileage, is it a driver or trailer queen)
- number of months of the year the vehicle sits stored
- where does he buy his fuel (Exxon, Shell, 'Bob's Discount Gas Bar', could result in different sulfur levels in the fuel)
- which fuel grade (regular or premium, again depending on the refinery could result in different sulfur levels in the fuel)
- did he use a fuel stabilizer
There are probably other things that should be considered as well before jumping to any major conclusions.
#54
Drifting
Same here - C5 for 13 years, C7 for the second year and never a problem.
#55
Good advice. When My fuel gauge quit working it cost me 3500 bucks to have them replaced. I saw it in the garage torn apart to get the tanks out. Major disassembly. Cant figure out why they didn't put an access door in the trunk
#57
Safety Car
I can understand, but in this particular instance there was a very well respected mechanic by the name of Paul Koerner that concurs with the recommendation submitted to him from GM engineers. I can't site the exact article on this subject, but it is not one mans opinion. And the fact that the gas tank is a closed system ensures the moisture concern is no longer a factor. Thanks.
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#58
So glad I have a Corvette which can be driven and enjoyed all year.
I personally think a Corvette likes to be driven more than it likes being parked.
I personally think a Corvette likes to be driven more than it likes being parked.
#59
Le Mans Master
Agreed that is why I store mine with less than 1/4 tank of gas.
#60
The difficult part for me, is I refuel when it hits 1/4 because I hate worrying about the gas gauge when I'm driving around (that last quarter goes fast, and if I want to floor it, as I normally do, I'd like to not have to worry, gee, do I have enough gas). And right now I have close to a full tank (Chevy dealer told me they could not get it to pass inspection with a 1/4 of a tank so before Thanksgiving, I gassed it up). So not this winter at least. It's sitting happily on the CTEK battery maintainer and likely will be that way until Spring barring some really nice weather and only then, if there's not a bunch of "de-icer" all over the DFW roads.