Evaporator replaced but freon smell remains.

[TomIbert]

A trusted long time mechanic shop replaced the evaporator on 2013 F150 about three months (300 miles) ago. I still smell Freon each time I start the truck. My cheap electronic detector will alarm for several seconds when I turn the key to ON.

I brought the truck back to mechanic and he reports system is fine. He explained if we drove it daily the smell would have gone by now.

Is lingering freon smell and detector alarming normal after 3 months?

We have very high confidence in our mechanic shop, but I believe he's wrong in this case.

Any suggestions of what we should do? Considering having him completely evacuate system and test for smell and alarm for couple of days.

Thanks for listening
Tom

[Cusser]

I still smell Freon each time I start the truck. My cheap electronic detector will alarm for several seconds when I turn the key to ON.

Is your detector in the air vent for this? Is this with the ignition and fan on, or the engine running and AC switched on? You didn't make clear....

[Tim]

Refrigerant has no smell, which could indicate you're picking up refrigerant/oil with your leak detector. If the core leaked, and the case was not cleaned during replacement. Well...

[TomIbert]

I still smell Freon each time I start the truck. My cheap electronic detector will alarm for several seconds when I turn the key to ON.

Is your detector in the air vent for this? Is this with the ignition and fan on, or the engine running and AC switched on? You didn't make clear....

Yes, detector in the air vent. When ignition is turned to ON, and blower starts the detector will alarm. If engine is or is not running, also if compressor running or not. I have only tested with controls set to Max AC. All tests have been after vehicle unused for at least a day.

[JohnHere]

It could be residual oil and maybe UV dye that you smell because as Tim said, refrigerant by itself is odorless.

My "sniffer," an older pro model, goes through a self-diagnostic routine and sounds off when it's first switched on to let the operator know that it's working and the sensor is intact. Could it be that your sniffer is doing something similar?

Meanwhile, continue to drive your truck. If the A/C performance degrades, then suspect refrigerant loss and take it back to the shop for additional diagnosis.

Chances are, the new evaporator core isn't leaking. But the block-style TXV connects to the evaporator and lines via individual joints, one or more of which could leak.

Why did you replace the original evaporator?

[TomIbert]

It had a large leak cause by organic matter (leaves) in the bottom causing the aluminum to corrode. The mechanic showed me the old evap, it just crumbled when touched.

I turn the detector on, then place in vent, then turn on fan via ignition, plenty of time for its startup cycle. It goes from quite to rapid beeping and back to quite in 15 seconds.

I feel better assured by the feedback. I suspect he didn't clean the inside of the evaporator housing and I'm smelling old oil.

Thanks for the info
Tom