I have found black oil on the left front hubcap of my 2004 KIA. I had the brakes worked on, then have had problems ever since with noises and swerving at times. When I took it back twice, the guy couldn't get it to do that when he drove it so nothing was done. I still have periodic brake problems, but not all the time. Would this be hydraulic fluid?

https://www.modifiedlife.com/2004-kia-optima-radio-wire-harness-guide/

It's most likely the left wheel bearing that's causing the noise, when turning to the right the weight of the car shifts to the left placing more load on the left wheel bearing and takes load off the right bearing.

This could be one of several things. My first thought is your brake pads are loose. They are usually retained in place by clips, springs or friction fit. Applying the brakes usually makes the noise go away. It could also be the hub bearing or one of the c.v. joints. Turn your wheel hard to the left or right while applying slight acceleration. If you hear popping or snapping, You have a bad c.v. Also check for loose parts such as the dust shield or the inner fender well!

oil from the rear on a front wheel drive vechile? Only thing off hand I can think of is leaky brake line.

mcdevito75 here, Most likely one of the CV joints in the axle on that side of your car. Have your shop check it out as if it breaks you"ll need a tow.

For the 2001 kia optima I have found the oil filter between the front passenger side tire and the engine. You can see it if you turn the wheels all the way to the left, although it helps if the filter cover is a bright color. To change it I had to remove the tire. I hope this helps.

Good morning! If you vehicle is equipped with center caps or hub caps remove them all and drive vehicle to see if noise is still present. Had a few problem hubcaps on these. Your local salvage yard should have these if noise goes away with hubcap removal. Have a great day!

Throughout my experience with Toyota's I have found that several times the hubcaps have made some weird noises. Try removing your hubcaps and driving your vehicle. If the noise still persists please let me know and I can ask u some questions and try to help you with your problem.

if its a ticking check to see if there is a screw or other object stuck in tire. if not look in between tire and hubcap for a rock or pebble, alst check treads.

Sounds like your wheel bearing is going if no other noises present when braking