1997 Honda Accord
2.2 liter F22B2 engine
automatic transmission

I have a small, intermittent fluid leak that I would like to identify.

So far it has only occurred 3 times over the course of a couple months
after I have parked in the garage. Each time it was about a teaspoon of fluid.

The first two times I did not notice it until it had dried up (long periods in
the garage due to covid). It did not evaporate but instead left kind of a
crystalline, powdery residue.

It has been a few days and one short trip in town since the last episode and
currently there is no puddle under the car.

It is a bright blue/green fluid that is slightly oily. I would say a little
more oily than the engine coolant.

Using an eye-dropper I took some coolant from the radiator and dripped it
next to the latest leak puddle for color comparison. In the attached picture
of the two puddles, the leak is on top and the coolant sample is on the
bottom.

The location of the puddle is about in line with the firewall, slightly on
the passenger side. I also found some blue/green discoloration that was
slightly wet located under a transmission bolt that is a few inches to the
passenger side of the oil filter that I believe is the point where
it drips to the ground. I have attached a picture of the discoloration
(the bottom of the picture is the front of the car).

Does anyone have any idea what the fluid is and where I should look for the
leak source?


photo 1. leak puddle on top, engine coolant sample on bottom

photo 2. wet, blue/green discoloration on bottom edge below bolt

 

Sure looks like antifreeze to me. Actually, the eyedropper sample looks like watered-down antifreeze. Or maybe the leak just picks up dirt as it's dripping down from the thermostat housing or the heater hoses.

 

Agree with JimBlake. Looks like antifreeze picking up dirt/grime while it drips down to the transmission.

There a few ways to locate the leak. Inspect the thermostat housing and the hoses going to the heater core through the firewall. The throttle body also has some coolant lines. Look for green staining or crystals on those components.

Alternatively, you can get a radiator pressure tester at the parts store and put about 15 psi on pressure on the cooling system. Then start inspecting hoses to trace down the leak.