Highway Construction Stuff on Car

TromboneAl

Give me a museum and I'll fill it. (Picasso) Give me a forum ...
Joined
Jun 30, 2006
Messages
12,880
They repaved the freeway near here, and after driving on the newly paved section in a hard rain, the lower half of the car is covered with a hard film of brownish sticky stuff.

It doesn't wash of conventionally, but it comes off the hub caps easily with WD-40 (essentially mineral spirits).

Should I use WD-40 on the rest of the car, or could it be damaging to the finish? Any other suggestions?

Thanks.
 
I don't know, Al.

I'd take it to a car detailing place. They will charge more than they would for a regular car wash, but whatever chemicals they use won't harm the finish.

I'm sure your local detailing places have been getting a lot of other cars with the same problem so by now they would be the experts.
 
I'd use mineral spirits or diesel fuel, then soap and water.
 
I would call the DOT and ask them how they expect you to remove it.
 
I would call the DOT and ask them how they expect you to remove it.

+1 - this happened to my sons car and a bunch of other people. Tar remover worked, but was a pain, and I ran out of the small amount I had. Before I read up or called, I just happened to try some OxyClean, and I was amazed how easily it stripped it off.

But your stuff could be different. The DOT should be able to help.

-ERD50
 
This stuff is some kind of oil, wax, or gum- ie it is not water soluble. Solvents for waxes or oils are things like gasoline, mineral spirits, kerosene, etc. These things are also not water soluble, but they are easier to attack with detergents.

THe other approach is to go at it directly with a super-detergent. Detergents have molecules that emulsify the wax and thus allow some solublility in water.

BTW- although gasoline works like a charm, I wouldn't recommend it. Used to scare me to use "pet ether" to dissolve fats and oils in the lab.

Any of these things will strip the wax from your finish.

I know it would hurt, but I recomend following W2R's excellent advice.

Ha
 
I just called Caltrans, and they've been getting a lot of calls on this. I was told to call the claims office, which I did, and left a message.
 
Cleaning anything involves chemistry. You must understand the surface being cleaned and the soil being removed.

Today's car paint is water based (was lead based in the past, but for environmental reasons, it has changed). It still looks great, but much softer that lead based counterpart.

Very strong detergents and other solvents not a good idea, It may look great after, but you may have damaged the clearcoat. This makes it easier for other soils (like salt, bug residue, acid rain, etc) to cling and start the paint breakdown process.

The soil you are talking about is likely oil based (Tar so organic and need a high pH type cleaner). I have found that the best tar remover is Tarminator (from Stoner and readily available).

Remember that these products need time to work, so apply and let it sit (dwell time) for a couple of minutes out of direct sun. You can tough the soil and it should just melt off...then you know you are ready for the next step. Then use a high pressure spray to remove it. It doesn't need to be much higher than 1000psi, but a fair bit of water (3 gal/min or more for proper impact) like at most self-service or coin operated car washes. It should come off fairly easily and tough spots may require a second application. So buy a couple of cans.

Or have a professional do it. Remember, many detail shops staff actually know very little about the chemistry of cleaning. Ask questions.

E86S54
 
Cleaning anything involves chemistry. You must understand the surface being cleaned and the soil being removed.

Today's car paint is water based (was lead based in the past, but for environmental reasons, it has changed). It still looks great, but much softer that lead based counterpart.

Very strong detergents and other solvents not a good idea, It may look great after, but you may have damaged the clearcoat. This makes it easier for other soils (like salt, bug residue, acid rain, etc) to cling and start the paint breakdown process.

The soil you are talking about is likely oil based (Tar so organic and need a high pH type cleaner). I have found that the best tar remover is Tarminator (from Stoner and readily available).

Remember that these products need time to work, so apply and let it sit (dwell time) for a couple of minutes out of direct sun. You can tough the soil and it should just melt off...then you know you are ready for the next step. Then use a high pressure spray to remove it. It doesn't need to be much higher than 1000psi, but a fair bit of water (3 gal/min or more for proper impact) like at most self-service or coin operated car washes. It should come off fairly easily and tough spots may require a second application. So buy a couple of cans.

Or have a professional do it. Remember, many detail shops staff actually know very little about the chemistry of cleaning. Ask questions.

E86S54

You seem very well informed. Can you give your suggestions for sap and bugs, (I suppose other tars are similar to Al's problem) -and anything else that we commonly get on our car finishes?

Ha
 
You seem very well informed. Can you give your suggestions for sap and bugs, (I suppose other tars are similar to Al's problem) -and anything else that we commonly get on our car finishes?

Ha

Tar, Bug guts & Tree sap are all organic and so an Alkaline detergent will work. Some better than others, name brands are usually best.

Road grime, wheels and rims usually have inorganic soils, so acid (low pH) type detergents work best. Break dust is toughest, so strong acid wheel cleaner.

If you use the right products, removing just about anything off a car is easy. The trick to these detergents is trying to use the weakest mixture that's most effective. Saves car paint, money and the environment.
 
Try Simple Green, full strength. I used to work at a new car dealer back in the early 80's when they used to coat cars with a brown sticky film to protect the paint jobs from road damage. They never sold this to the public back then, noe they do, but it should do the trick.
 
Try Simple Green, full strength. I used to work at a new car dealer back in the early 80's when they used to coat cars with a brown sticky film to protect the paint jobs from road damage. They never sold this to the public back then, noe they do, but it should do the trick.

Simple Green is a brand name that makes everything from car wash soaps to roof cleaners. So depending on what that sticky film was and which Simple Green product you chose, it could or could not work.

I would read the label on dilution and not go full strength if say 1/16th would do. Many commercial car wash soaps are diluted as low as 400:1 if they are hyper concentrates.

Also, remember than in the early 80's car paint was lead based, much tougher.
 
I just called Caltrans, and they've been getting a lot of calls on this. I was told to call the claims office, which I did, and left a message.

Careful about doing any cleaning yourself, regarding any reimbursement. This happened to a co-worker years ago, after he had done many hours of work himself cleaning it up. All they would do is reimburse him for the materials if he provided a receipt. But if he took it to a detailer and spent hundreds, they might have reimbursed that 100%.


Tar, Bug guts & Tree sap are all organic and so an Alkaline detergent will work.

Road grime, wheels and rims usually have inorganic soils, so acid (low pH) type detergents work best.

Great info, thanks. Could you give us specific examples of acidic and alkaline detergents? I just sort of know detergents as wetting agents, I never really considered their pH or associated that with different types of detergent.

-ERD50
 
From the title I thought there were a couple of pavers and a bulldozer or two on your car.

As for the muck, I had good luck with kerosene soaked paper towels plastered on, wait a few hours then use more to remove, then soap an water.
 
Thank you for contacting WD-40 Company concerning using WD-40 on car paint. We appreciate your interest in our product. WD-40 can safely be used for your application and will not harm the paint finish on your car.
Thank you again for contacting WD-40 Company. Please let us know if we may be of further assistance.

Best regards,
Eva Zabowski
WD-40 Customer Service

 
And it tastes better that way too !

Why did I think that anyone would take me seriously.

It does involve chemistry. Fatty organic molecules (both aliphatic and aromatic) in mayonaise are similar to tar and glue. It has worked for me in the past. No risk of danger to the auto finish with this method. I admit that other things may be more dangerous, costly and maybe work better.

Free to canoe
 
At work, we use orange degreaser to get road tar off construction vehicles.

Like this stuff.

It isn't this brand, but it's essentially the same stuff. Takes a few applications sometimes, but I bet your WD-40 will work fine, just takes a lot some times, probably because its so diluted.

-CC
 
Tar, Bug guts & Tree sap are all organic and so an Alkaline detergent will work. Some better than others, name brands are usually best.

Road grime, wheels and rims usually have inorganic soils, so acid (low pH) type detergents work best. Break dust is toughest, so strong acid wheel cleaner.

If you use the right products, removing just about anything off a car is easy. The trick to these detergents is trying to use the weakest mixture that's most effective. Saves car paint, money and the environment.

I haven't noticed the pH being listed on a cleaning product -is there a quick and easy way to determine that?
 
It turns out they were trying a new product for the paving. Usually this isn't a problem, but they've gotten a lot of calls.
 
Update

None of the things I tried got it clean, so I filed the claim, and today they sent some detailers to my house, and they did a great job cleaning and waxing the car.

The detailing company is based in Texas, and does this all over the country.
 
None of the things I tried got it clean, so I filed the claim, and today they sent some detailers to my house, and they did a great job cleaning and waxing the car.

The detailing company is based in Texas, and does this all over the country.

No wonder California is broke.
 
Back
Top Bottom