Replacing Battery In C5
Thread Starter
Heel & Toe
Joined: Nov 2008
Posts: 16
Likes: 1
From: Scottsdale Arizona
Replacing Battery In C5
Are there any unusual problems or challenges in replacing a battery in my 2004 Vette? ie loss of codes, etc. I have a lead acid battery and will be replacing it with an Optima battery. 
Pro
Joined: Apr 2006
Posts: 552
Likes: 0
From: Alton Illinois
just make sure the connections are tight. if it is not in a daily driver, you might consider a battery tender to keep the charge up. optimas do not like getting discharged. if you are a little short on $ as i usually am, you might read some "battery replacement" threads after you do a search. i put an autozone gold in mine and it is just doing fine. i also use a battery tender.
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
I just replaced my old AC Delco 78/7yr with another ACD 78/7yr and it was an easy 10 minute job. The old battery was weak but didn't leak. The new one was even easier to install with the littel side loops/handles. Dropped it right in, tightened the wire bolts and hold down bolt and away we went. I believe it's a 13ml for the hold down bolt and 8ml socket for the wires. You will need a long extension for the hold down bolt and a short thin socket for the wires or a closed/open ended 8ml wrench. You will need to push pretty hard on the fuse box to fit the socket on to the positive terminal if you don't have an open ended 8ml handy. FYI
Then you just need to put your key in the ignition and hold down the lock and unlock buttons simultaneously on the fob. The horn should beep and your fob should reset.
Then you just need to put your key in the ignition and hold down the lock and unlock buttons simultaneously on the fob. The horn should beep and your fob should reset.
Last edited by Johnny Hardcore; Jan 2, 2009 at 11:24 PM.
Le Mans Master
Joined: Nov 2004
Posts: 8,718
Likes: 20
From: Dyer IN
Cruise-In IX Veteran
never had to reset a fob, its a pretty easy job 10 minutes, 13mm with long extension, being an 04 its top mount posts so prly a 10 mm for that
IMO dont waste ur money on the optima
IMO dont waste ur money on the optima
Drifting
Joined: Jan 2005
Posts: 1,969
Likes: 201
From: Lyons Il
2023 C5 of the Year Finalist - Unmodified
battery
Had to change mine last spring. It does seem that the fuse box can cause some issues with getting the threads to line up correctly. Just make sure you finger tighten them first. One thing I can tell you is a weak battery can cause all kinds of weird gremlins that might make you think you have real problems. When my battery died, I heard a clicking under the hood. Even when I removed the battery, I still heard the noise! Go figure. When I put the new battery in, no issues whatsoever and I did not have to reprogram anything but the radio. I replaced mine with an AC Delco unit. I have heard that normal batteries do not last much longer than 3 years in these cars due to the heat. I have heard mixed reviews with Optimas so I really do not know what to think with them.
Le Mans Master
Joined: Nov 2004
Posts: 8,718
Likes: 20
From: Dyer IN
Cruise-In IX Veteran
origional ac delco in the 01 and car sits for weeks at a time sometimes and still fires right up
04 has top mount terminals so no messing around with sidepost and clearance issues from fuse box
04 has top mount terminals so no messing around with sidepost and clearance issues from fuse box
Pro
Joined: Aug 2008
Posts: 727
Likes: 2
From: Clemson Sc
Dont waste your money on the optima. I sell them and im not at work so i can bash them. hahahahaha 1 in 2 come back defective. Get a standard battery.
Keep in mind only a few battery manu. in the whole country so they all come fro mthe same place generally. The only difference is the plastic case. example, johnson controls makes optimas, autozone, advane auto parts, and other places batteries.
Keep in mind only a few battery manu. in the whole country so they all come fro mthe same place generally. The only difference is the plastic case. example, johnson controls makes optimas, autozone, advane auto parts, and other places batteries.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
when you change the battery, set up a wire harness from another car to your corvette. ( I use two number 10 wires about 20 feet long, one black and one red.)
open both hoods, clip the positive of the donor car to your alternator positive terminal (the big red wire) and the other wire from engine ground to engine ground.
The other car will keep your car alive until the new battery is installed, and wires disconnected.
Note:
be extra careful when doing this, because the battery in the corvette will be charging when you disconnect. So, disconnect the negative wire first and it's a piece of cake.
open both hoods, clip the positive of the donor car to your alternator positive terminal (the big red wire) and the other wire from engine ground to engine ground.
The other car will keep your car alive until the new battery is installed, and wires disconnected.
Note:
be extra careful when doing this, because the battery in the corvette will be charging when you disconnect. So, disconnect the negative wire first and it's a piece of cake.
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Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
The replacement procedure is not that different than any other car. If your concerned about your radio presets going away, then I would just write them down before you start.
As others have said, disconnect the negative cable first and re-connect the negative cable last. BTW, the wrench size for the side terminal bolts is 5/16". It has been 5/16" ever since GM first went to a side terminal battery and has remained so. I use a small 6 pt box-end wrench for the side terminals. That way I can't over-torque them.
BTW, I'm on my second Optima. My first one lasted over 5 years and wasn't dead but my voltage levels were dropping so I changed it as a precaution. I would recommend the 34/78 Optima.
P.S. If you hear some "clicking" sounds from the car when disconnecting/re-connecting the battery cables, this is normal. The sound is coming from various relays.
As others have said, disconnect the negative cable first and re-connect the negative cable last. BTW, the wrench size for the side terminal bolts is 5/16". It has been 5/16" ever since GM first went to a side terminal battery and has remained so. I use a small 6 pt box-end wrench for the side terminals. That way I can't over-torque them.
BTW, I'm on my second Optima. My first one lasted over 5 years and wasn't dead but my voltage levels were dropping so I changed it as a precaution. I would recommend the 34/78 Optima.
P.S. If you hear some "clicking" sounds from the car when disconnecting/re-connecting the battery cables, this is normal. The sound is coming from various relays.
Safety Car
Joined: Mar 2007
Posts: 3,518
Likes: 37
when you change the battery, set up a wire harness from another car to your corvette. ( I use two number 10 wires about 20 feet long, one black and one red.)
open both hoods, clip the positive of the donor car to your alternator positive terminal (the big red wire) and the other wire from engine ground to engine ground.
The other car will keep your car alive until the new battery is installed, and wires disconnected.
Note:
be extra careful when doing this, because the battery in the corvette will be charging when you disconnect. So, disconnect the negative wire first and it's a piece of cake.
open both hoods, clip the positive of the donor car to your alternator positive terminal (the big red wire) and the other wire from engine ground to engine ground.
The other car will keep your car alive until the new battery is installed, and wires disconnected.
Note:
be extra careful when doing this, because the battery in the corvette will be charging when you disconnect. So, disconnect the negative wire first and it's a piece of cake.
I just bought a new battery from Advance Auto and had them install it too. They connected a small battery to my lighter socket to keep the radio presets while they changed it.
By the way there is no reason to go with an Optima battery. Ratings are inferior to others and more costly.
I think the Optima mania came from the idea of leaky batteries on the early C5s and battery technology from many years ago. Any current battery should not have any concern over leaking. Like the "Red Top" type? Must be more valuable words
Be smart. Buy the best battery for the best value and it will not be an Optima by a very long shot, not even close.
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
Use some baking soda on the tray and surrounding areas
I replaced mine with a 78 from Sams Club. I thoroughly doused the area under the tray (4 bolts to remove it) with a gallorn or two of warm water and a heavy dose of baking soda. Get the wires, vacuum lines and the metal and then rinse thoroughly. Had the infamous vacuum line deterioration and no change to any vents on the HVAC due to no vacuum to the switch under the dash. Go for it.
BIGHANK
BIGHANK
Safety Car
Joined: Mar 2007
Posts: 3,518
Likes: 37
When I went to replace a battery in one of my C3s a couple years ago I was thinking "All right, now is the time to step up to an Optima" like I had read about.
Looking at the actual ratings in the store was a real eye opener compared to what people say.
As the military folk say these days "Whiskey-Tango-Foxtrot!"
And I wanted people to think it through before spending money.
Looking at the actual ratings in the store was a real eye opener compared to what people say.
As the military folk say these days "Whiskey-Tango-Foxtrot!"
And I wanted people to think it through before spending money.
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
When I went to replace a battery in one of my C3s a couple years ago I was thinking "All right, now is the time to step up to an Optima" like I had read about.
Looking at the actual ratings in the store was a real eye opener compared to what people say.
As the military folk say these days "Whiskey-Tango-Foxtrot!"
And I wanted people to think it through before spending money.
Looking at the actual ratings in the store was a real eye opener compared to what people say.
As the military folk say these days "Whiskey-Tango-Foxtrot!"
And I wanted people to think it through before spending money.
I've had good results with Optima. See post# 9.
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
Melting Slicks
Joined: Mar 1999
Posts: 3,211
Likes: 167
From: Rochester Hills Michigan
I just bought a new battery from Advance Auto and had them install it too. They connected a small battery to my lighter socket to keep the radio presets while they changed it.
By the way there is no reason to go with an Optima battery. Ratings are inferior to others and more costly.
I think the Optima mania came from the idea of leaky batteries on the early C5s and battery technology from many years ago. Any current battery should not have any concern over leaking. Like the "Red Top" type? Must be more valuable words
Be smart. Buy the best battery for the best value and it will not be an Optima by a very long shot, not even close.
Drifting
Joined: Apr 2000
Posts: 1,655
Likes: 15
From: Jeffersonville In
Cruise-In I Veteran
Cruise-In II Veteran
Cruise-In III Veteran
The Optima's respond, hold up better if kept fully charged. They don't like sitting around , as in a non daily driver. I didn't have good results with a red top. Three years and it was shot. AC Delco in the 98 Pace Car lasted 7 years. I am now running the Sears 7 year 78, with 5 years free replacement. No more Optimas for me.
Burning Brakes
Joined: Sep 2003
Posts: 1,085
Likes: 0
From: Broken Arrow OK
I replaced mine with a 78 from Sams Club. I thoroughly doused the area under the tray (4 bolts to remove it) with a gallorn or two of warm water and a heavy dose of baking soda. Get the wires, vacuum lines and the metal and then rinse thoroughly. Had the infamous vacuum line deterioration and no change to any vents on the HVAC due to no vacuum to the switch under the dash. Go for it.BIGHANK
BIGHANK
Intermediate
Joined: Apr 2005
Posts: 43
Likes: 0
The Optima's respond, hold up better if kept fully charged. They don't like sitting around , as in a non daily driver. I didn't have good results with a red top. Three years and it was shot. AC Delco in the 98 Pace Car lasted 7 years. I am now running the Sears 7 year 78, with 5 years free replacement. No more Optimas for me.
This is the last one for me.
Norbert