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Recognize this yellow fluid?

hi - a few days ago, I found this on the bottom of my 96 Lexus ES 300. See image here…
any ideas what this yellowish fluid could be? It’s around the middle to right from the drivers seat perspective.

Thank you!

There are no images. I would start by checking all fluid levels, esp the brake fluid. Sometimes you have to crawl under the car (esp if you drive a '96).

Sorry, the link I posted for image didn’t work. Image is here.

Have you checked the coolant level in your radiator and overflow tank? If its OK now, I would keep an eye on it. From you description of the location, I would suspect that you may have a leaking heater core or a leaking heater hose at the heater core.

If you coolant gets too low, you could overheat the engine and blow a head gasket. You are not losing very much now so watch carefully. If it is the hose, it could get bad very quickly. If it is the heater core, It wont get bad as quickly, but its a lot more expensive to repair.

But then it could just be a stray cat.

How far forward is it? Look under the car when it’s parked to see what is above the puddle.

Ya know what that looks like? Sulfur.

All gasolines contain some amount of sulfur. And if there’s a small leak in the exhaust system the water produced from the combustion proccess can cause the water/sulfur to drip onto the ground.


is the liquid oily? Yellow could be coolant if your car uses this type, or maybe power steering fluid? Have you checked all of the fluid levels?

Put some baking soda and water on it. If it bubbles, it’s runoff from the battery/tray. Do you see lots of corrosion around the battery?

Otherwise, yellow anti freeze comes to mind.

Thank you for your responses. The coolant in the reservoir is green. Coolant was a bit low in the radiator so I topped it off. The Sulfur theory is interesting so I will look into that further. Battery looks clean.

I also think it sulferized water dripping from a small exhaust leak.
Not big enough to make noise, but enough to drip condensate.

Do you spend more than 30 seconds idling to warm the car up?

Yes, sometimes I do spend more than 30 seconds idling the car to warm it up.

Warming up idling tends to increase the condensate in the exhaust pipes, which stay cool longer.
Car exhaust is mostly water vapor and carbon dioxide, which forms an acidic soup that corrodes the pipes from the inside out.

I don’t recognize the stuff. It seems to be corrosion or material deterioration (like a failing insulation or a failing ceramic) of some form. Whatever it is, it shouldn’t be there. Honestly, I think the best way to find out what it is is to get the car up on a rack and look with a good work light.

It looks like power steering fluid mixed with rain water.