freon/oil leaking out of ac vents, how to repair

My 93 4.0L ranger now has 170,000 miles on it.

About 8 years ago, the original R12 ac system would no longer hold a freon charge more than about a 1 year so I retrofitted to r134a freon with r134a oil with stop leak.

System has worked fine all these years but now a terrible freon/oil sickly sweet smell is leaking out of the ac dash vents causing headaches in people with the vents blowing in their faces whenever the ac is turned on and continuing shortly after being turned off.

Guess it's the evaporator or some o ring seals leaking.

Not sure how hard it is to determine the point of leak and repair or even access the evaporator.

Any advice or suggestions besides, not to use the ac till repaired, would be great.

Thanks

The evap core shouldn't be that hard to do on a 93. I'd just get a new evap and throw it in.

Thanks,
I suppose it must be the evap core, because if it's an o ring I suppose those connections are outside the evap box and therefore not able to contaminate the cab ac vents correct.

Bingo.

And FWIW to get oil on the registers and give people in the cabin a headache from the fumes it has to be a pretty massive leak.

Even though I see it looks like the evap is contained in a two piece plastic box, it looks like a headache to remove.....I'll have to find a outline on the procedure.
Why does it leak, it shouldn't have rusted....hmmm

I just replaced mine. You'll have to take out the 5/16"s screw holding the box together. You're also supposed to change the drier when you change the core. I'd also suggest all new orings. I also took the whole box off the firewall, removed all the factory insulation (it was falling apart, mine's a '94), cleaned the box, replaced insulation with dynamat extreme. Also new blower motor and resistor. Recharged the system, adjusted the dash cables, now blowing top notch and 45* at the vents in 105* Texas heat. Yeah, it's work, I didn't half ass it, But now it's working probably better than if it was new. All I need now is a new headliner to cover the new dynamat extreme.

Also forgot to add, I couldn't find a new gasket for the box to firewall connection and my old one was compressed beyond sealing. I cut about a foot off the bottom of an Army green foam sleeping mat, made 2 new gaskets to fit the box and 3m spray adhesived them to the old gasket. No hot air leaking in the cab when the A/C system is off now!!

jimtmcdaniels said:

Even though I see it looks like the evap is contained in a two piece plastic box, it looks like a headache to remove.....I'll have to find a outline on the procedure.
Why does it leak, it shouldn't have rusted....hmmm

Click to expand...

The evap core can be in temps ranging from 30* to 110* and under pressures as low as 25 PSI up to 130 PSI during normal system operation (or lack thereof). All that hot/cold and low pressure/high pressure cycling takes it's toll on the metal. It's just soldered aluminum. Eventually one of the tube or one of the joints gives under the expansion/contraction cycles and it starts to leak.

When you get it out grab the end of the one line and just start bending it back and forth and see how long it takes to break it off. Same deal with the guts, just on a smaller scale.

Thanks guys.

Metal fatigue eh.

Well those extreme sways in pressure explains why it only leaks when on and then only sometimes.

Hope one from the bone yard lasts.

I know it's definitely not coolant that I'm smelling.

I have box of generic assorted o-rings, I guess the rings aren't special as long as it's the right size..

How do you get to the evap core?

I have a 1994 Ford Ranger and have had a problem with the A/C going on 5 or 6 years now and it is getting worse each year. I recharge the system and after a while (hours or day) I hear a HISS coming from the center dash area and soon after the A/C is no longer cooling. Could this be the evap core (not vary familiar with A/C terminology). If so, how do I get to it?

Fuel vapor recovery - vacuum purge valve bad - bypassed

Discovered the problem and repaired!

The ac is still working fine and no coolant leaks!

It was the fuel vapor recovery system!

I discovered the hard to find smell origin was coming from the vapor canister.
Gasoline additive chemicals they put in our gas can smell weird bad.
Sure seemed to smell like freon or some new chemical in the coolant.

I discovered the purge valve that allows engine vacuum to get to the canister was no longer working whether 12v was applied or not.

E-bay wanted $35 min for a new valve so I decided to simply install about a 5" long piece of 1/4" poly pipe in place of the purge valve.

I read in a vehicle the computer activates the purge valve typically while not at idle but my ranger seems to run fine with it activated all the time.
I may decide to buy the replacement valve down the road if the lean running seems to effect it..

The smell is gone and it seems I no longer get the occasional brief rough idle-hot day slight vapor lock.

Hope this post helps anyone with the same problem.


8/14 update - REPAIRED - Discovered the REAL problem and repaired!

The ac is still working fine and no coolant leaks!

It was the fuel vapor recovery system!

I discovered the hard to find smell origin was coming from the vapor canister.
Gasoline additive chemicals they put in our gas can smell weird bad.
Sure seemed to smell like freon or some new chemical in the coolant.

I discovered the purge valve that allows engine vacuum to get to the canister was no longer working whether 12v was applied or not.

E-bay wanted $35 min for a new valve so I decided to simply install about a 5" long piece of 1/4" poly pipe in place of the purge valve.

I read in a vehicle the computer activates the purge valve typically while not at idle but my ranger seems to run fine with it activated all the time.
I may decide to buy the replacement valve down the road if the lean running seems to effect it..

The smell is gone and it seems I no longer get the occasional brief rough idle-hot day slight vapor lock.

Hope this post helps anyone with the same problem.