Said It Here

Small yellow fluid leak around AC Schrader valve

A tiny amount of yellowish-green fluid around the Schrader valve can indicate a minor refrigerant or oil seepage despite a mechanic claiming the system is normal. Because shops rarely use tracer dye to confirm small leaks, owners are left guessing whether the valve needs immediate replacement or if it is just residual fluid.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Spray it with soapy water like you're looking for a tire leak to check for bubbles
  2. 2
    replacing the rubber washer at the end of the internal rod
  3. 3
    replacing the exterior screw
  4. 4
    tightening the packing nut

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/AskMechanics1 person · September 2026

I have a 2015 Ford Focus with only 33K miles on it. A few weeks ago I happened to notice a very small amount of this yellowish-green fluid around my Schrader valve.source ↗

Here's the deal though, no one has ever tried to put tracer dye in my car to check for leaks, ever.source ↗

Fietsen01 · r/AskMechanics · 1 upvotes
r/Plumbing1 person · September 2026

Have a leak that is coming from what seems behind the screw when I turn on the hose.source ↗

Brendan1620 · r/Plumbing · 1 upvotes

Where this came up

People with this problem also raised