atazerxes

I have a 1997 Lexus ES300 with an issue that appears to be related to heat and car battery/alternator system. So here is the problem: during the summer months (and especially when the car has been idling for long periods, 10 minutes or so) the car will not have enough power to start the engine, for example after turning car off to go in store. When you come back out to start the car you can hear the starter clicking but there will not be enough power to turn engine over and we have to use a portable battery charger/jumper to jump start the engine. It will crank immediately with this jumper units help. Also, if you let the car cool for several hours it will also start. The problem only occurs during hot weather and with a fair amount of city driving or idling as mentioned earlier. It has no problem during cooler months and doesn't occur at all. In addition, when the car has become hot from this type of driving or idling you can actually see the dash lights or headlights grow bright and dim as you rev the engine. Its pretty significant to see. The Toyota dealer has replaced the alternator a couple times along with several new batteries and the problem persist. What kind of problem could cause the battery drain as I have described? Any help would greatly be appreciated. Again its a 97 Lexus ES300 with approximately 130K miles.

lexpilot

If you keep trying the starter when it clicks, does it ever engage?
I've had this exact problem on two 97 ES's. The solenoid contacts and the plunger get carboned up after a while and even thought it clicks and tries to pull the connection is not made. Pull the starter and put this kit in the solenoid: http://www.discountstarterandalterna...FY-DaQodZRoO9w
Or one like it. I have an original starter on mine with over 350K miles, I've put this kit in twice. The Denso starters last forever. Just not the solenoid contacts.

Oro

+1, sounds like a failing starter. That would be candidate #1 and where the dealership should have looked first if the battery tested sound.

Next is contacts like grounds, relays, etc. Easy to test before pulling starter.

Loopie

I have the exact same problem with my 99 es300. Every summer, the battery drains and I have to replace it. The problem starts when I run the ac unit. It will work fine for a few days but then, while driving it, the ac light will automatically go out and the radio will start to blink off and on. Then the car will not start without being jumped.

I recently bought an OBDII unit that tests the battery and the alternator. Coincidentally, my car battery died the other day. I had to get a jump to get the car started. The OBDII instructions require that the tests be done with the headlights on. I performed the tests per the instructions and the results were that my battery and my alternator were good. I ran additional tests running the air conditioner concurrently with the headlights as instructed and the results were that my charging system was bad and should be checked. Repeating the test several times with and without the ac running produced the same results each time; good charging system when lights only were used, bad charging system when lights and ac were used.

Does this indicate a problem with my charging system or my ac system?