Yellow spray under the hood

[rojohi]

Hey folks,

I did various searches, to see if this has come up before. My apologies if I missed an easy answer.

The past weekend, I washed the car, and decided to clean up the engine bay, as I haven't done it yet since the end of winter. I noticed a yellow spray underneath the hood. It had a crusty texture, so it is definitely dry at this point.

I looked elsewhere in the engine bay, and do not see it anywhere else.

Any ideas as to what it may be?

Thanks for your help.

 

[Fountainhead]

No idea but it appears to have been thrown up there by the serpentine belt. I'd get a really bright flashlight and one of those like 3" rotatable mirrors from an auto shop and look down that side of the engine.

 

[TriangleHeat]

The only other time I saw this was in an older 8th Civic I had. Incidentally the power steering line was leaking and it was positioned near the belt and pulleys so I assumed that was being slung up from the pulley. The residue didn't have an oily feel though, seemed more like dirty water dried.

Like Fountainhead said, you need to check the area out with a flashlight. Might just be rusty water from a pulley being thrown up? Is it oily feeling? If it was oil no amount of drying would remove the oiliness if you rub it between your fingers.

I wish there was an easier way to tell if it's rusty water (rust isn't magnetic and the flame test would probably be hard or not work at all). The easiest chemical method of identifying if it's rust is you can try collecting a sample of it and spray it with one of those iron removal sprays for car paint that they sell, the kind ffor dissolving ferrous stuff like iron or steel rail dust that's embedded in car paint? Like Sonax Fallout Remover spray or maybe even a color changing wheel cleaner that changes color on ferrous dust from brake pads.

 

[rojohi]

Just an update; the car went in for service and the techs went through it.

Could not find any leaks anywhere, checked the belts/pulleys, car is running perfect. They don't think it's oil or any other auto fluid; they suspect something got flung up by the belt s there is no new spray since I wiped it down.

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