I'm looking to replace my battery in my 99 bird, but I have a question about the battery group sizing? What does it all mean lol?

I found a newish battery for sale online from a 99 grand prix, the car was scrapped and the owner pulled the battery. Will the battery have any fitment issues in the bird? I don't have the battery group of the battery being sold online but if I know which groups fit our cars I'll know if it's compatible.

Thanks

 

Your car takes a group 75 battery. The one you found online could be a 75 or 78. 78 is similar to a 75, just a bit longer. A 78 should fit with a little work.

 

As stated above, group number has to do with the physical case size of the battery, and these cars are group 75 from the factory. My Nova takes the larger group 78 battery, and frankly I wouldn't want the hassle of trying to stuff that into the F-body mounting location.

I have no idea what group size a '99 GP takes though.

 

Awesome guys thanks for the info.

 

I'm looking to replace a group 75 battery as well. 2 weeks ago I had settled on getting a Die Hard Gold....the same "brand" that gave me 6 years. When I went into Sears to buy the battery I noticed they had eliminated the vent/fill caps. It's now a "maintenance free" battery with a 3 yr warranty. That's it. That's all well and good. But, if I want to try and get to the 4-5 yr mark, I want to be able to check the fluid levels. My last battery had the plates seriously uncovered at the 2 yr 10 month point (when I bought the car...previous owner's problem). It was heavily sulfated and took almost 2 cups of water. A series of charges over several days brought it back to life. If that battery had been maintenance free, it never would have lived much past 3 years. So Die Hard Golds are out by having no service caps.

With nearly all of the auto parts stores having batteries made by Johnson Controls does it really matter which of these you get? Autocraft Gold, Duralast Gold, AC Delco Professional Gold. Prices are all somewhat similar at $110-$130. Looked at the Walmart Everstart MAXX, BJ's Exides, and Interstates but don't get a good vibe from those in reading reviews. Consumer Reports rates the Walmart batteries rather highly. No Kirkland for me since I don't have a Costco membership. Won't even consider Optima or higher tech brands due to pricing and only having similar warranties to wet batteries.

Any favorites these days? Most of the Gold's have a 3 year replacement warranty. AC Delco might be 4 yrs. Many don't offer a pro-rating beyond that any more. I'm getting tired of looking though. Can't even find a big box or auto store who sells AC Delco.

 

I continue to stick with the AC Delco Professional series, it has the longest warranty (4 years) although not as long as previous versions of this battery. I bought a group 78 recently for my '71 and it was still the version that had serviceable caps, I have not bought a group 75 recently but will be getting one for my '98 sometime this year or next. I buy them from a local GM dealer with whom I have a business account, so the price is reasonable.

 

The warranty appears to be down to 42 months on AC Delco gold. The pricing was right at one local store at $101 + core charge. I was about ready to go get one when they told me they are "maintenance free" sealed batteries. I guess the mfg's don't want to risk do-it-your-selfers messing with the wrong fluids being added, sticking screw drivers down into the plates, etc. Guess, I can't blame them. But without the ability to water the battery, they are basically ensuring the batteries will fail shortly after the warranty expires. May have to go with the Autocraft or Duralast as those do have fill caps....Die Hard gold and AC Delco professional golds do not. The Duralast gold seems to be the only one offering anything beyond the replacement period (2 yrs prorated after the first 3 yrs). Most of the golds offer a 3 year 100% replacement warranty. I see something on another AC Delco distributor site that lists their 75 PG's as 6/7 yr batteries. Don't know what they mean by that.

http://www.batterysales.com/delco-pro.cfm

Is my concern over a maintenance-free battery justified or not? Can't they lose significant water over 3-4 years?

 

The two best options would be either an Optima red top 75 dual post or an East Penn made 75 dual post. They are both AGM style batteries and generally hold up better then acid filled batteries with a little bump in CCA and are made to fit these cars. I got my East Penn branded one with a Duracell sticker from BatteriesPlus. If you not going with an AGM, I would just go with the cheapest acid filled battery because AC Delco is a lot of money for a conventional battery, if your going to spend that kind of money might as well step up to an AGM. And when your comparing warranties look at how long it's FULL REPLACEMENT, many places will tell you it's a 60 month warranty with it being only full replacement for the first 12 months or so, you gotta read the fine print when comparing battery warranties.

 

You're right, it seems they have dropped the warranty further, now to 42 months. Did you actually get to look at the newest AC Delco group 75 with the highest (gold) warranty? I wonder if they just told you it was "maintenance free" because technically even the ones with the caps are supposed to be maintenance free as well. I'd be interested in seeing what the newest ones look like at this point, I guess I'll be finding out soon enough since I'll need one at some point this season.

To be honest, even with the removable caps, I have never serviced a modern battery. I treat them all as maintenance free, as this is how they have been presented/sold/marketed for quite some time now. The current group 75 in my '98 is now slightly over 6 years old, and still holds a great charge, and I have never so much as removed the caps. I can let it sit for 3 weeks and the charge is still over 12.2v, which is plenty to start the car. After a normal drive cycle, the voltage will be in the 12.6-12.7 range, and stay above 12.5 for over a week. If the car sits for 4 weeks or more (such as during storage), then I hook up the smart charger at the lowest amperage until it completes its charge cycle.

It's hard to even justify replacing this battery, except that it's 6+ years old so really it *should* be time. Point being, I guess it's not the end of the world if the caps are not present, since I've already been treating mine as though they weren't there but still have gotten excellent life from the battery. The previous version of this same top level group 75 from AC Delco didn't have the caps either; I don't think I saw these caps until about 2006 or 07.

That link seems to show the old warranty structure, not sure why it seems to disagree with the other listed warranty periods for the Delco batteries.

 

The lack of fill caps on the ACD Group 75 PG was told to me by both the Chevy dealer and the Auto Parts store. As it turned out, that Chevy dealer gets their batteries from that same Auto Parts store. The Chevy dealer didn't have a gold on hand but they went back and looked at the Silver...no fill caps.

The more I read about maintaining batteries there's no reason the ones for our little used F bodies shouldn't last 6-10 years (or longer) if properly charged. If the batteries get below 12.2-12.4 v or the plates become exposed, they start to sulfate. I may just check out the ACD PG75. If I maintain that on a trickle/float charger during down time, there's no reason it shouldn't last 4-6 years. I got 6 years out of my Die Hard after nearly killing it by having a portion of the plates exposed for months. And my charging the past 3 years was every 2-3 weeks at higher initial rates (6-10 amps). A proper float/3-4 step automatic charger should do a lot better. As a caution, overcharging can be as bad or worse than no charging. I saw a U-tube video where a mechanic had 9-13 year old "cheap" batteries on his outside cars that were still in near perfect charge. On the oldest and cheapest battery he had a 1 watt - $15 solar charger connected to the dash. He also preferred batteries with fill caps. I guess if you plan on going 13 yrs or longer, fill caps are a good idea.

 

Costco actualy recently stopped selling Kirkland batteries and carry Interstate batteries, either way they're made by Johnson Controls.

 

You may find that the Gold level AC Delco still has the fill caps, as this was the case for the group 78 I recently bought for my Nova. The lower level warranty versions (such as "silver") used the no-cap design for the group 78 as well. So it stands to reason that the high level (gold) might still be using the same fill cap style as the "gold" level 78 and previous high-level 75s. But again, going back to ~2004, the highest level AC Delco group 75 didn't offer fill caps either (I still have the highest-level Delco battery that was in my '98 from '04-'09, in my basement), it wasn't until I needed a new battery for my '02 car in 2007, or early '08, that this new cap design was in service for Delco.

I've allowed my current 6+ year old battery to drop as low as 12.0v, but usually no lower than about 12.1-12.2, prior to a recharge during storage. Normally I hook up the smart charger, starting at the lowest 2 amp setting, once per month during the winter and let it do it's thing. It can be used as a continual tender as well, but I don't like having the wires running all over the garage all winter, so I just hook it up once every 4 weeks or so. During the on-season I'll only hook it up if the car has gone longer than 3 weeks without running, which might happen once or twice during the spring/summer/fall.

I've usually replaced them every 5-6 years in my garage queens, but never had one actually die. I wonder how long they could go with good charging practices? I guess 10+ years is possible, since I too have known at least one person to get that sort of life out of batteries, but I have never tried myself. I've just always dumped them around the 5-6 year mark as a matter of maintenance. I might consider going longer with this one, since it's still working so well and holding a good charge.

 

You're right. That's what I found. I took a trip down to the parts store to pick up a 75 PG for $100 (they charged me $98). And sure enough, battery caps. Their other branch, and every other "expert" I talked to today including the GM dealership said "no caps - maintenance free." Sheesh. Had there been a decent photo of the battery top anywhere on line I'd have not wasted 2 hours today farting around with other style "gold" batteries that only cost more.

NOW THE DOWNSIDE: The battery doesn't snug down tight with the clamp seating on the rear lower casing rib of the battery. After half a dozen attempts I gave up and pulled the battery out....only to find a couple small drops of what appeared to be battery acid on the tray top. An hour earlier I had cleaned up everything with windex and wiped it dry. I can only conclude this battery is slightly off in construction. With the clamped torqued down to max, the battery pivots easily in all directions and the front edge easily lifts up...just like in the installation video below. The old Die Hard Gold never gave me this problem, it was always snug. With the battery core turned in already no way to compare the two. If that rib were just 1/8th-1/16th inch too low, that would be enough to mess things up. I'll check things in the morning and if they're still messed up, and there are more moisture drops under the battery, it's going back.

Fwiw, the first battery they gave me was already 5 months old and had a couple beads of battery acid on the sides of the case. I asked for another. Never had so many problems just replacing a simple battery. The electrolyte level as delivered is approx 1/4-3/8" from full in most of the cells.

This video sequence at the very end of step 8 (tightening the battery) shows the same clamping set up as our LS-1's. Not surprisingly, the guy tightening down this battery clamp says to "ensure the battery is tight." He applies a little force to it and it wobbles all over the place. It ends there. Huh?

http://www.carcarekiosk.com/video/20...eplace_battery

 

That issue with the battery being loose seems to be a common problem for many 4th gen owners, but it's a problem I haven't had with any of mine to date. Usually, the problem is due to the front lip on the battery tray/overflow bottle combo cracking, thus not providing a firm hold. I had a friend with this issue on his '02 SS, so I removed his overflow bottle and sure enough, there was a crack in the battery tray lip. We got a new one from the dealer and the battery went in sung enough that you could shake the entire car with it.

The most recent 75 PG Delco battery I've bought was for my '02 Z28 back in 2013, and that one looked and fit exactly the same as the one currently in my '98 from 2009. Both are very snug, literally snug enough to shake the car with.

It's certainly possible that sloppy quality control has lead to some battery cases/mounting ribs being a bit too small. But before you return the battery, if you have to pull it out again I'd recommend doing a very close inspection and stress test on the front lip of the battery tray. I know your car is very low mileage and well cared for, but that '02 SS I mentioned above was also a low mileage garage queen (had about 32-36k on it at the time) when that battery tray lip started to break. Considering you can lift and pivot the battery though, the problem is likely not a cracked lip (unless it's entirely broken away) but rather something off with the external dimensions of the battery. Still worth a look though, just in case.

 

RPM WS6 nailed it. The front lip has BROKEN away somewhat, though still decently attached. Missed that last night....frankly, never expected it. I'd have probably found it this morning in better light. My last attempt last night was to put a spacer under the battery tray to ensure that battery rib made good contact with the clamp. But with that cracked front lip, the battery just slides away as more clamp pressure is applied. From the last battery installation to sometime this week, I must have applied that final fracture force. $98 battery, meet $60 "battery tray." Can't believe the tray and coolant reservoir are just one large molded part....the battery tray is part of the coolant system! I didn't know that until today. At least it's not the battery's fault. I'm still not sure how I initially put a small crack in the battery tray front edge lip because that battery was held tight just 2 days ago.

I was curious if 3500 psi plastic epoxy could solidify that 1/2 way cracked front battery tray joint. But while I was measuring the distance behind it for a backing spacer during the 24 hr curing process I snapped the darn thing off. So much for that idea! So how about putting a spacer off the car's sheet metal to replace the function of that plastic lip? That gap is approx 1-1/2" wide. Found an appropriate wood spacer and cut it to battery length. It sits partially on the tray and wedged up against the end of a bolt that's exactly opposite of the clamp. Battery seats tight and resists twisting. The spacer sits away from the painted metal surfaces of the front end because of that bolt. A couple of firm rubber blocks would work too. If this were a beater this would sure beat paying $60 for a "coolant" part that's still perfectly fine. No doubt, at some point I'll spend the other $55-$60, ideally when there's really a problem with the coolant reservoir. I would want the exact GM item with stamped part number. Several on line sites carry these at $20 less than my GM dealer. They all appear to be exact OEM replacement items (#10402687). You still have to reuse your old radiator hose assembly, reservoir filler cap/dipstick, and battery clamp down too.

 

This is an unfortunate problem that just seems to happen with some of these. Not sure if it's tied to a history of someone over tightening the battery, or perhaps age/heat, but so far mine has held up. I have a spare OE one tucked away in my parts stash just in case I ever need it.

Glad you spotted this before spending a bunch of time swapping out batteries though.

To add to this, you also have to reuse the original grommet that plugs into the top of that bottle to seal the overflow hose/line in place. The new ones, even from GM, don't come with a new grommet. It's a bit of a pain to extract from the old bottle, but it can be done. Some people have sawed the old bottle apart to get it out, but if it's still fresh and pliable (as it should be on your low miler) you can likely pry it out, as I did.

 

Thanks for that info RPM WS6. I just assumed the grommet came with that overflow line. But, it is shown in the expanded diagrams as a separate part number. While my grommet is probably pliable enough, I see no reason at the time to risk playing with the coolant set up and risk more problems that currently don't exist. In the meantime I'll keep an eye out for a quality used/new setup at the right price....maybe even check out some auto recyclers. Picked up a new AC/Delco GP65 PG battery for my daily driver as well (had an Exide that lasted 4 yrs). I'm an A/C Delco guy for the time being. thanks to you.

Fwiw, when I was charging both of those batteries, I'd get them back to 12.65 volts. But within 4-24 hours they'd be right back to the 2.25-2.30 volt range. I had no obvious problems with the GP 65 on my daily driver, but it was responding similarly as the dying battery in my Camaro. In the Camaro I was getting those full range pulses on rpms and speedometer on startup....and trip monitor resets to 0....in other words low battery voltage. A fresh charge right before my drive would ensure that didn't happen. But, on that last drive, a wait of only an hour before driving and I got those same indications. In fact, I had charged it the day before too figuring I might go out. Those were the last straws. And getting stranded on a "fun drive" would not be much fun. 6 years was plenty of life on that Die Hard. For all the batteries I've ever put in the 2 dozen or so daily drivers I've had over the years, I've never had a battery die early (ie in the first 1-3 years).

 

I just put a new group 75 AC Delco in my 02 last night only to find it was loose. After reading this and checking tonight, sure enough the front lip is cracked closest to the radiator.

 

Oh crap! Another one bites the dust! Sorry for your loss Z28 6 Spd. Would be nice if there was a sticky on all the "simple" things that you can easily brake on your F-body by not paying real close attention. Mine was apparently fine one day....and then bad the next.

Maybe there should be a LS1Tech "service bulletin" put out about about this like the roof panel bubbles. I knew something wasn't quite right as I was really torquing down on that battery clamp. But, it was still moving at the same rate and still wasn't holding the battery tight. All I can say is we gotta be very careful that everything is aligned properly with the clamp horizontal before going too far into applying torque (>10-20 ft lbs?) onto that bolt. It's probably not a bad idea to give that battery bracket some additional help over the years with some type of spacer behind it. Age might weaken the plastic but there's not all that much heat in my engine bay even during a Connecticut summer. Have to lean towards applying Gorilla force. Maybe an earlier owner did that too? Or some lunkhead at a auto repair shop/dealership? It only takes one time to get it started.

If I could do mine again, I'd want to try putting some plastic epoxy (3000+ psi) into the crack and letting it set. It might be enough strength to keep it intact along with a spacer. A smaller crack might be recoverable if the epoxy can be pushed fully into the crack. I have a feeling that even with a perfect battery tray you can crack this lip when applying too much force while the battery clamp or battery is not properly seated/aligned.

 

I first tried to order the grommet separately when I replaced the bottle in my friend's SS, but my GM parts guy said it could not be ordered. This was a few years back, but I seem to remember it being discontinued? In any event, I tried to order it again when I bought the spare bottle for mine and it wasn't available then either. So reuse of the original might be the only option at this point, or perhaps a close-match PCV grommet might work as well; it won't be visable underneath the battery and there is no pressure in the bottle as it's just an overflow, so the point is really just to keep debris out. The overflow line just pulls right out of the top, and then you can work to pry the grommet from the bottle (or cut the bottom of the bottle open and push it out from the inside, as some have reported doing.)

Glad you were able to find the cap style you wanted. I'll likely be picking up a new one for my '98 this year as well.

With the low amp/trickle chargers, it seems that you need to get the initial surface voltage pretty far above 12.65 for a complete and lasting charge. Normally when my automatic charger completes, the voltage will be somewhere close to 12.8-12.9 volts, and then drop off to 12.6x over the next 24 hours if the car is not touched. At that point, it'll stay over 12.5 for 1-4 weeks depending on the age of the battery.

I really can't complain about my current Delco 75 PG, it's still doing extremely well for a 6+ year old battery. I'd like to see how long it'll go, but like you said I'd hate to get stranded some time.

My guess is that over tightening or perhaps even under tightening, which would allow the battery to shift and slam into that lip, are the most likely causes for this. No telling what might have happened with a previous owner, etc. When I bought my current '98 it still had the assembly line battery in it, so there hadn't yet been a chance for anyone else to damage it. I've always been very careful about getting it tight but not too tight, since I've had battery tray/hold-down issues like this with other cars before. It wasn't until many years later that I started to notice the pattern with how common the breakage of this item is for the F-bodies.

I think the epoxy fix you suggested would work well in a situation where it's still just a fracture and not yet fully broken. It might even work for a more complete breakage if applied well. I also wonder if JB Weld might do the trick for this.