Well that sucks

[CheemsK1500]

Did you lose air co

So interesting take someone on Reddit has. They say it’s not Freon coming through the vents. They say my heater core is leaking and what I was seeing and smelling was engine coolant vapor coming through the vents.

That would explain the yellow liquid that dripped on the carpet from under the dash, and dripped on the ground below the passenger side door.

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Did you lose air conditioning function though? If you did not, then it is the heater core. If you did lose AC and find large amounts of engine coolant/antifreeze in the box, then that means you have possibly blown both a heater core and an evaporator core.

The heater core plays no part in the AC function, you can bypass it entirely and still have AC if your AC system is fully functional, in fact many do so on purpose during the summer months to avoid having the hot heater core air blend with the cold evaporator core air. You should go ahead get you a set of AC manifold gauges to verify the AC system is even charged; that alone will tell you if anything blown or has a major leak in the AC system specifically.

 

[Blackbird]

I won’t know until this weekend. As soon as the vapor appeared I turned the truck off and have not turned it back on since. I was afraid it would damage something. I’m headed out of town but will fiddle with it on Sunday.

 

[Sad Sack]

You would never see the refrigerant as a liquid - its only liquid under the high pressures generated by the compressor and immedialy flashes off to vapor when moved to a lower pressure environment (which is how the system works - gas starts as a liquid, then flashes off in the evaporator-absorbing heat in the process, then goes thru the compressor and turned back into liquid-releasing heat at the condensor). If you are actually finding liquid dripping out, a blown heater core starts to make sense.

Especially if the vapor smells "sweet" like "burnt" sugar.

 

[75gmck25]

The smell of antifreeze is very distinctive, and I assumed most folks would recognize it immediately. Nothing at all like you would smell from an A/C line refrigerant leak.

 

[Hunter79764]

It definitely looks like you blew a hole in the evaporator (evaporator looks a lot like a heater core). Relatively easy to replace the evaporator, but as was mentioned, once you open it up there are other parts to check and update.

- if it’s already R134a, you can probably just replace parts, pull vacuum to remove the moisture, and then recharge. A/C shops usually use an automated machine to vacuum and recharge, but you can DIY with a vacuum pump and inexpensive gauge set.
- always replace dryer/accumulator and orifice, and use new green o-rings on all fittings. They may have also switched the orifice from GM white to Ford Blue (blue is supposed to work better with R134a), or even added a variable orifice (mixed reviews of how well they work).
- compressor and condenser should still be fine
- hoses may be fine, but should be updated to new barrier hose if they are original and not in good shape

I’m sure I’ll think of more items, and there are other things that may have failed. For example, many converted systems add a high pressure cutout switch, since R134a pressures are higher than R12. Your original system only had a low pressure cutout, which protected the compressor. Excessive pressure may be why the evaporator failed.

/\ This if you need to replace anything.

If the yellow liquid is oily like it looks, then you aren't seeing freon, you are seeing the oil mixed with the freon. Press the schrader valve just a tad and see if you get a spray of anything, if it's dead, then you most certainly blew the evaporator. If you get a pressure release, then the heater core makes more sense. But unless you were overheating severely, you would get a lot more coolant and a lot less vapor coming out of the vents.

And idling with low airflow, then revving at idle, will make the highest operating pressure, but not on your evaporator. When off, your pressure will be the same everywhere in the system based on temperature (call it 100 psi for the right idea), revving in the heat with a weak fan will get you 3-400 psi discharge pressure on the condenser up front by the radiator, but will DROP pressure in the evaporator down to 50 or so. Idle and cool temps would probably give you the highest suction pressures, but they will still be lower than what it is when you turn the system off and it all equalizes. In other words, when it popped is just a fluke.