I have a huge oil stain in my garage floor about four feet in diameter . From what my neighbors told me the previous owner had an old car in there for years. I want to get rid of this stain and possibly paint the floor. I have an electric pressure washer up to 1500 psi. What can I use to get the oil out?

have you attempted to just wash it out with the pressure washer?

i think that would be your best bet, and then if it didnt come out, go at it with something else

I've used castrol super clean. It rocks. What is your garage floor? sealed concrete?

This sounds a little crazy, but, try some wheel cleaner like Armor All Wheel Cleaner

have you attempted to just wash it out with the pressure washer?
In my experience, these will force the oil deeper into the concrete, perhaps giving you problems later.

Since it sounds like the stain is old, I'd start with a solvent (I use engine cleaner), let it do it's job, perhaps helping it along by scrubbing with a broom. Might take a couple passes to get the worst cleaned-up.

Since you're thinking of painting, take a look at what the different paints recommend for prep - probably muratic acid. This should help take care of anything residual that would reduce longevity of the paint.

I agree with the muriatic acid (available at Home Depot)

BUT

This stuff is nasty and should ONLY be used in a well ventilated area. I would highly advise getting one or more household electric fans ready if you intend to do this in a garage, and do NOT splash this stuff on anything, even diluted, that you wouldn't want it on.

I would advise you to test this on concrete in a well ventilated area, first, to see what you are getting into.

Oh, by the way, muriatic acid is a good way to remove rust from steel. Just be prepared to prime the newly cleaned metal as soon as possible because it will start getting surface rust from the humidity.

In my experience, these will force the oil deeper into the concrete, perhaps giving you problems later.

Since it sounds like the stain is old, I'd start with a solvent (I use engine cleaner), let it do it's job, perhaps helping it along by scrubbing with a broom. Might take a couple passes to get the worst cleaned-up.

Since you're thinking of painting, take a look at what the different paints recommend for prep - probably muriatic acid. This should help take care of anything residual that would reduce longevity of the paint.

Absolutely correct...what he said! :thmsup:

Behr Concrete Cleaner FTW...