Driveway Stain - What is it?

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Call_Me_Op
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Driveway Stain - What is it?

Post by Call_Me_Op » Sat Jun 01, 2019 10:19 am

A contractor visited my house yesterday and parked his van on my asphalt driveway for about 1 hour. When he left, I noticed a stain on the asphalt about 2 feet by 5 feet - very noticeable. The stain is not dark like oil - it looks like a water stain. It is under where his front passenger side was. I figured it was AC condensate so figured it would dry overnight. When I got up this morning, it was still there and had not faded at all. I got my hose and rinsed the area of the stain for a full 15 minutes this morning. My driveway is sloped, so all the water drained to the street. But after the water dried, the stain was still there - as prominent as before. I do not notice a smell from it.

Does anyone have any ideas what this stain is? I don't think I will bother mentioning it to the contractor, because it's not worth any hassle.
Best regards, -Op | | "In the middle of difficulty lies opportunity." Einstein

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cheese_breath
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Re: Driveway Stain - What is it?

Post by cheese_breath » Sat Jun 01, 2019 11:14 am

Radiator coolant? Brake fluid?

I'd let him know just in case his truck might be damaged by losing too much of whatever it is.
The surest way to know the future is when it becomes the past.

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Call_Me_Op
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Re: Driveway Stain - What is it?

Post by Call_Me_Op » Sat Jun 01, 2019 11:18 am

cheese_breath wrote:
Sat Jun 01, 2019 11:14 am
Radiator coolant? Brake fluid?

I'd let him know just in case his truck might be damaged by losing too much of whatever it is.
Good idea. Thanks cheese_breath.
Best regards, -Op | | "In the middle of difficulty lies opportunity." Einstein

runner3081
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Re: Driveway Stain - What is it?

Post by runner3081 » Sat Jun 01, 2019 11:22 am

Hydraulic fluid? Roofer's trailer made a stain on our driveway with that.

We have tried everything, oven cleaner, bleach, baking soda, powerful soaps, still there. The best thing that lightened it was vinegar. The sloped driveways are hard, can't let anything sit on it, just runs down.

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Cheez-It Guy
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Re: Driveway Stain - What is it?

Post by Cheez-It Guy » Sat Jun 01, 2019 11:36 am

runner3081 wrote:
Sat Jun 01, 2019 11:22 am
The sloped driveways are hard, can't let anything sit on it, just runs down.
Put a cloth or towel on stain. Soak cloth or towel with selected cleaner / solvent.

Brake fluid is a good guess.

Dishwashing liquid and scrubbing with a nylon-bristled brush can really help some oily-type stains, but even if you remove the stain, you may change / lighten the color of your concrete for a while. Eventually, it tends to go back to “normal” color as lichens and such grow back. The degree of change may depend on whether you normally clean or pressure wash your driveway. I don’t, so the change can be stark.

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CABob
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Re: Driveway Stain - What is it?

Post by CABob » Sat Jun 01, 2019 11:39 am

Call_Me_Op wrote:
Sat Jun 01, 2019 11:18 am
cheese_breath wrote:
Sat Jun 01, 2019 11:14 am
Radiator coolant? Brake fluid?

I'd let him know just in case his truck might be damaged by losing too much of whatever it is.
Good idea. Thanks cheese_breath.
And the contractor may have a better idea what it is. My bet is on radiator fluid. In any case that is a pretty large stain that I think the contractor would like to know about and chances are he is already aware.
Have you tried vinegar?
Bob

Hockey10
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Re: Driveway Stain - What is it?

Post by Hockey10 » Sat Jun 01, 2019 12:19 pm

I estimate that 4 of every 5 contractors that have worked on my house in the past 25 years have left a stain on my asphalt driveway. Most of the stains gradually fade away. I get the driveway sealed about once every 5 years. So from that day until the next time someone comes over to work on the house, the driveway looks perfect.

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Call_Me_Op
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Re: Driveway Stain - What is it?

Post by Call_Me_Op » Sat Jun 01, 2019 12:48 pm

Update: After a lot of rinsing and sunlight, the stain has faded significantly. I think it is water soluble - maybe even AC condensate. I think what happened is because my asphalt is old and porous, the fluid that caused the stain was absorbed overnight. That would explain why freshly-applied water would evaporate faster than the fluid that caused the stain. But with a lot of sunlight today, the asphalt appears to be drying.
Best regards, -Op | | "In the middle of difficulty lies opportunity." Einstein

Rifampin
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Re: Driveway Stain - What is it?

Post by Rifampin » Sat Jun 01, 2019 7:55 pm

Spraying brake parts cleaner on it will take it right out. Give it a try. I would recommend getting the non-chlorinated type, less noxious to the lungs.

gmc4h232
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Re: Driveway Stain - What is it?

Post by gmc4h232 » Sat Jun 01, 2019 8:25 pm

Probably tobacco spit.

Teague
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Re: Driveway Stain - What is it?

Post by Teague » Sat Jun 01, 2019 9:09 pm

AC condensation fits the timing, location, description etc. better than anything else that I can think of.
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Workinprogress
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Re: Driveway Stain - What is it?

Post by Workinprogress » Sun Jun 02, 2019 12:12 am

Not likely AC condensate, that is just water from the air.

Many newer work vehicles have a radiator surge tank on the firewall. More on the passenger side than the driver side that has the brake booster in the way. Antifreeze will soak into the surface and leave a mark for a while.

Next, it may have been a diesel vehicle. Diesel filters are in many places under the hood. A leaking filter or lines can make a pretty big mess and not give the driver a problem.

Last, in my opinion would be power steering fluid. A clear, mostly odorless, oil. Some smaller work trucks have a rack and pinion steering, that could be leaking, but not for long at that rate. (2'x5' puddle).

If it is on concrete, most of the oily things can be cleaned by spray parts cleaner from an auto parts store. Spray it on and wipe it off with rags.

If it is asphalt, anything that cleans oily stains will dissolve the asphalt a bit, and leave you with a bigger mess.

Any type of stuff to clean the stain should really be mopped up vs rinsed down the drain for the fishes to deal with.

Good luck.

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