I hope that someone can tell me what my problem might be.. I drove my C5 Corvette to the airport this morning, and when I got there and stopped the car, smoke/steam was coming out of the right side of the hood where it meets the windshield.

I opened the hood and there I could see that the battery was "venting" steam. The steam smelled really acrid, like battery acid. I got back in the car and checked the voltmeter and it was rock steady just under 13.. I started the car and it starts fine. All electrical items work in the car.. I shut the car off and let it sit for a few minutes and the steam stopped. I had to get to work so I drove to the office and the same thing is happening.. I watched the volt meter all the way back to the office and it never exceeded 13! It never got higher than it was supposed to..

Do you think it is just the battery? Could it be the alternator as well? I have a big fear of the battery shorting out and the car burning (melting) to the ground.. Please advise. I am stuck at the office until I hear back from you guys!

Thank you very much in advance!

[ 11-24-2003, 09:01 AM: Message edited by: Go69 ]

Either one of two ideas; 1. Heavy discharge with the battery aiding the alternator, or 2. an overcharge occuring from the alternator.

The voltmeter on the dash is not a good quantitative measuring device. Its only purpose is to indicate a voltage, whether charging, starting, or battery. Use a bonafide voltmeter to measure these voltages.

Heavy use of battery will cause steam. It may be the battery could be of age to require replacement to say a slipping belt to a defective alt.

I would probably take the car to a shop having an equivalent to VAT-28, Vat-40 for testing and see what the results show. I would suspect a battery replacement.

The next thing I'd do after replacement would be to remove the battery, and drench the battery area, all around, including the area going up, as in fumes, with a baking soda solution with water. Follow with a cold water rinse. This will neutralize the remaining acid and the water will rinse away the residue.

I don't think a battery steams when it is discharging. The only way it steams is during the charge cyle, because you are adding energy to it. I would think your alternator is overcharging the battery somehow.

You may have a dead shorted cell within the battery which is drawing current into the battery from the alternator.

If you have a shorted cell, the car won't start if you leave it off for any period of time.

Thanks for the ideas guys. I am going to go to a local auto parts store and replace the battery at lunch time.

I am going to go for the Optima Dry Cell, or completely incased battery so that this does not happen again.

Thanks for the ideas. I will keep all of you posted.

I'd watch out before pouring water and baking soda in that area. Believe there is electronics situated below the battery around the firewall. Also the inner fender is enclosed on the bottom of a C5. You won't get the water/acid/baking soda to flush well. May have to unbolt the inner fender to clean things well.

John,
I agree with you. It looks like the battery is enclosed in a sort of "box" that is composed of the hood on top, the firewall to the rear, a shelf underneath it, and two sides that separate it from the engine compartment, with the inner fenderwell acting as the last side..

I will check for adequate drainage once I get the old battery out. I guess if I start pouring water in, and don't see it escaping under the car, I will know that the water is trapped somewhere and try and figure out how to evacuate it at that poing. I guess once I neutralize the area, I can always use a shop vac to pull the water/Baking soda/acid mix back up from the top if I can see where it is trapped, and if I can get to it with the vacuum nozzle. It is really cramped under that hood!!!

Thanks again for the ideas guys. I was so stressed out this morning. I just had the car serviced on Saturday and told the mechanic to fix everything that he found wrong with it.. $1200 dollars & two days later this happens. I guess he could not predict the battery would take a dump.

It is the original battery and it lasted 5 years. The car still had the original serpentine belt, brake pads, coolant, and battery with 60K miles on it. Pretty good if you ask me. I called my local AutoZone and they have the Optima dry cell batteries for this car for $119.. They are only one mile from my office so I will be going there immediately after work to buy, and install a new one. Thanks for the advise again-I really appreciate it.

Update!

Replaced my battery yesterday. I bought the Optima dry cell-Red Top battery which all of the people over at corvetteforum.com are raving about.

The battery set me back $159.99+ tax (I think the guy over-charged me as he quoted me $119.99 on the phone and I neglected to look at the receipt until I got home). Anyway, this seems to have cured the problem.

Now, I think I will have to switch to the Optima for my trunk mounted Camaro as well! Those sure are sweet looking batteries! They weigh less than a standard battery as well!

In regards to rinsing out the acid, I still have not gotten around to doing it yet, but did notice that the FUSE BOX resides right beside the battery! Not a place to go spraying a water hose! I am going to mix up some baking soda and water in a spray bottle and very carefully spray the affected areas.. There are drain holes in the shelf that the fuse box and battery sit on, and under that it leads directly to the ground. So drainage should not be an issue.

Thanks for all of the replies. You guys and gals are like my second family who never asks to borrow money, tools, or my car.

Originally posted by Go69:
Update!

Replaced my battery yesterday. I bought the Optima dry cell-Red Top battery which all of the people over at corvetteforum.com are raving about.

The battery set me back $159.99+ tax (I think the guy over-charged me as he quoted me $119.99 on the phone and I neglected to look at the receipt until I got home). Anyway, this seems to have cured the problem.

Now, I think I will have to switch to the Optima for my trunk mounted Camaro as well! Those sure are sweet looking batteries! They weigh less than a standard battery as well!

In regards to rinsing out the acid, I still have notice that the FUSE BOX resides right beside the battery! Not a place to go spraying a water hose! I am going to mix up some baking soda and water in a spray bottle and very carefully spray the affected areas.. There are drain holes in the shelf that the fuse box and battery sit on, and under that it leads directly to the ground. So drainage should not be an issue.

Thanks for all of the replies. You guys and gals are like my second family who never asks to borrow money, tools, or my car. not gotten around to doing it yet, but did