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Air conditioning evaporator

I have a 1999 Dadge dakots sport and the air conditioning evaporator needs replaced. I’m good with tools and the vehicle is not driven allot because it’s my fourth car but it’s in excellent shape. Should I try this myself

No, but only because the refrigerant is not supposed to be vented to the outside air.

Find a licensed AC shop.

Before you consider doing it, pick up a Haynes or Chilton’s repair manual and see what’s involved. The evaporator is usually located around the same area as the heater core, which means there could be a significant amount of disassembly to access it. You also need to have the A/C system evacuated before removing any components.

In short: It’s not an impossible job, but it’s not real easy either. If it can be done without digging half of the dashboard out, I’d say do it.

Well? If you’re willing to remove the dash so that the heater/AC plenum can be removed, sure! That’s the most expensive part of doing this type of AC repair. Also don’t forget to replace the filter drier too.

Once the evaporator/filter/drier is replaced, take it to an AC shop so they can evacuate the system, and properly charge it.


The evaporator is located by the radiator. It’s the condensor that’s by the ductwork.

You have that backwards.


Yup, you’re right, I do have it backwards. Thanks for correcting me.

What WAS I thinking?

You say evacuated. There is not coolent left in the sytem to my knowlede it all leaked out. There was a puddle in the floor mat and when your turn on the heat is has a rotton smell. I had someone replace the condensor that they said was bad and it worked for a day until the coolent leaked out. I was pissed that he had no real knowledge of what might be wrong

Stop the presses!

Are we talking about refrigerant (the substance used in the A/C system), or are we talking about coolant (the substance used in the engine’s cooling system)?

If the OP does not know the difference between coolant and refrigerant, I seriously question his ability to do this repair, even with the aid of a repair manual.

The “puddle” and the “rotten smell” sound like the OP is talking about a leaking heater core, rather than an A/C evaporator. Or, perhaps, both the heater core and the A/C evaporator need to be replaced.

Perhaps the OP could post back with better information about this vehicle and its problems. Even if it is not driven “allot” (sic), the OP needs to know exactly which parts are in need of replacement.

I’m thinking it’s from the heater core. But there is no refrigerant in it either. It does not heat well and will not air condition. I have been thinking the heating core has been bad for some time. I need to get a book. I’m assuming from your responce that both the evaporator and heating core could be causing me my problem?

I don’t see anything about smells or puddles in the OP’s question. They’re just asking if the evaporator is something they should take on.

And besides, if there’s leak in the evaporator, there’s no refrigerant left in the system. So there’s no reason for reclaiming of refrigerant.

Are we going off on tangents?



That reference was not in the OP’s original question. He added it in a later response. After budd2049 reminded the OP that the A/C system would need to be evacuated, the OP responded by saying:

“You say evacuated. There is not coolent left in the sytem to my knowlede it all leaked out. There was a puddle in the floor mat and when your turn on the heat is has a rotton smell. I had someone replace the condensor that they said was bad and it worked for a day until the coolent leaked out. I was pissed that he had no real knowledge of what might be wrong.”

It sure sounds to me like the OP is confusing the heater core with the A/C evaporator, and is confusing refrigerant and coolant. Or, maybe there is a heater core issue, plus an A/C system issue. It is all very muddled and unclear.

The heater has not worked well for a few years. Not sure why. The air conditioner quit and I took it to a mechanic that said it was the condensor and I had it replaced. The AC worked for one day after the replacement. The next day I turned it on and no AC and there was a puddle on the floor mat under the glove box. It may have been coolent. The refrigerant was gone. There is a rotton smell from the vents when the fan is turned on. I’m at a loss for what is wrong. Is the heater core and evaporator gone and what is the connection between the two. I have worked on many cars but not AC problems and I’m tired of pissing away money. I’m looking for answers without just replacing shit. Is this clear enough now?

It really is illegal for you to do it because you almost certainly don’t have the facility to properly pull any remaining refrigerant out of the system and sequester it. However it’s almost certainly an R134A system (greenhouse gas but not an ozone layer destroyer), not an R12 system and, as you say, there probably isn’t much left. The planet would probably survive your tackling this yourself. That’s between you and your conscience.

On a more pragmatic note, the heater core and A/C evaporator in many cars is next to impossible to get to. You almost certainly can get to it, but it’s likely not to be a lot of fun.

And it’s by no means clear that the problem with your air conditioning is the evaporator. It could be the compressor or one of the hoses or fittings. There could be several problems.

As several folks have told you, that puddle/rotten smell thing indicates that you quite likely have a problem with the heater core or an associated hose as well as the air conditioning system. You may have to remove the A/C evaporator in order to get to the heater core. OTOH, that problem could be something as simple as a blocked A/C drain hose that is backing water condensed on the evaporator back up into the cabin where mold is now growing. Given your scenario, I suspect that you may have that problem, but since you say the heater hasn’t been working right in recent years, I think you may have other problems as well.

And as Tester indicates, it’s important to replace the drier and pump down the A/C system with a vacuum pump – which you almost certainly don’t have – before recharging the A/C system.

What I’d suggest is wait until Air Conditioning season is over in a another month or so, then pay an Auto A/C shop, which may have time on its hands to find the leak(s), tell you where they are, and pump the system down. They have the tools and experience to do so. You don’t. Then, if you are so inclined, dismantle the under dash heater/air conditioning unit and figure out where the puddle came from. Fix that and reassemble. Fix anything else that seems to be within your capabilities. Then get the A/C guys to do the rest of the job.

Thank you that is the best advice I have received yet. I thi8nk I will dismantle the dash and take a look. The truck runs great and looks like brand new even though it has 200,000 miles on it. I drive my Ram 1500 with the Hemi now and it just sits so I have time. I trusted the last guy that says it was the compressor and it wasn’t. It’s got to be the evaporator or lines. Maybe it’s just a simple leak. The puddle only occured once when the refirerant leaked out and that was a year ago so I doubt there is any of that left. My new son in law is a now unemployed mechanic and I need to talk him into taking on this project. He could use the money and I trust him, he just got caught up in this economy mess. Thanks again

I think you may have two problems—a leaky heater core (causing the puddle, lack of heat, and rotten smell), and a leak somewhere in the air conditioning system–which may be the evaporator, but could be anywhere in the system. The easiest way to find the a/c leak is look for oily spots on the air conditioning lines–the leaking refrigerant will take oil with it. If you could charge the system enough for it to run, add some fluorescent dye, and drive it with the a/c on for a day, it would help you find the a/c leak.