Bought a 2013 GS350 about 3 weeks ago. I was looking in the engine bay today and discovered that the battery was leaking. It was wet around the recessed fill caps and down in grooves around the top edge and down on the battery tray. There was also some that had dripped on the positive cable sheath as it runs along the side of the battery. There wasn't any on or near the terminals. It seemed to be coming out from around the fill caps.

I did not want to pull the battery out tonight to do a full clean so I doused the leaky areas in a baking soda solution and then later water until it seemed all the acid was neutralized.

Battery appears to be new and the Carfax report stated that the dealer I bought it from had replaced the battery. So now I'm left with wondering what the problem was. What is the most likely cause? Overcharging alternator? Defective battery case?

 

Did you remove the fill caps to see if the acid was too full - at the very top of the cells? If so, I suspect the battery was probably overfilled when it was initially installed and the normal charging has caused the acid to leak out around the fill caps.

 

OEM battery should have a translucent case, you can shine a flash light at an angle to see the acid levels.

 

Aren't most car batteries sealed nowadays? If I ever had a battery that could be filled, I never knew it or had it come up. I had run accross in my Lexus manual that there were some pages devoted to checking water levels in the battery so was aware that my battery might not be sealed but I wasn't sure. As I said, the dealer where I bought the car said they replaced the battery.

Anyway, since I've never dealt with checking/filling batteries I didn't want to monkey around with it until I knew what I was doing. I had to deal with the acid last night in the cold and dark with baking soda solution and didn't have the time or inclination to see if I could get the caps off. I will tonight or this weekend. If the caps do come off it might be kind of hard to do so. They are recessed into the top of the battery with only a small channel in front of each cap where the leaking acid was running out. I guees I can try to pry with a screw driver in that gap.

If it's not simply a bad or overfilled battery, my concern is that the alternator or regulator are bad and overcharging leading to the overflow. After checking to see if any more acid had come out this morning (I didn't see any), I put a voltmeter on the battery and it read 12.34 V which is lower than I would have thought it should be. I've got an OBD scanner in all the time and on the way to work battery voltage was reading anywhere from 13.7-14.3 V which looked normal to me.

 

Dealer I bought it from replaced it with a black cased battery.

When I get time tonight or this weekend I plan to yank it out and cleanup any remaining acid and then I'll see if I can get the caps of and check levels.

 

Your initial post referred to the battery leaking at the 'fill caps' so I assumed whoever you bought your car from installed a battery that was not sealed.

I personally would take the car to some place like National Tire and Battery, who specializes in all types of batteries and vehicle charging systems. They can quickly determine what the problem is, and what caused it...and clean things up and fix it for you.

 

good luk taking out the battery. it took me awhile trying to take the battery out because of the clips