E46 Fanatics Forum banner
  • Hey everyone! Enter your ride HERE to be a part of September's Ride of the Month Challenge!
1 - 16 of 16 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
In a few weeks I'm going to rip out my dash and replace the leaky evaporator in my 2004 M3. Looks like a long job, but not terribly hard. A great way to get know my M3!

I'm seeing other people mention replacing the drier and the expansion valve while it's all open. Looks like an extra $300 in parts from Tischer, and I'm wondering if it's really worth it. What do y'all think?
 

·
Registered
Joined
·
5,768 Posts
Literally anything you've ever wanted to deal with under your dashboard :). You'll never have it this disassembled again!
 

·
Registered
Joined
·
4,998 Posts
In a few weeks I'm going to rip out my dash and replace the leaky evaporator in my 2004 M3. Looks like a long job, but not terribly hard. A great way to get know my M3!

I'm seeing other people mention replacing the drier and the expansion valve while it's all open. Looks like an extra $300 in parts from Tischer, and I'm wondering if it's really worth it. What do y'all think?
If the system is open for more than one hour I rec replacing the Drier. I would replace the expansion valve as well
 

·
Registered
Joined
·
107 Posts
You absolutely should replace the receiver/dryer. Anytime the system is opened, the receiver/dryer is exposed to outside air and moisture which will effectively keep it from functioning properly. As far as replacing the expansion valve, it's not an absolute necessity if you are sure it isn't leaking. I would at the very least replacing the o-rings that are associated with the expansion valve. Personally, I would probably replace it 'while I was in there' because you don't want to have to pull most of it apart to change it out later on-but it's up to you. Most of my auto a/c experience has been with E30's, and on those systems the expansion valve is a known weak spot that is one of the first places to leak.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #6 ·
Sounds like the message is clear: Replace the expansion valve and drier! Now, the evap itself I'm going to get that from Tischer. As for the drier and expansion valve, are those safe get aftermarket?
 

·
Registered
Joined
·
10,212 Posts
Depends what you mean by aftermarket. If you get first line manufacturers, then that's good. Off brand name, and you'll live to regret this.

Would be really amazing if you get some good pics of this while you have this open. I know I've seen the DIY for dash removal, but the more pics and the closer you show things, the more we appreciate it.


BTW, how did you diagnose that the evaporator needed to be replaced? Story of that would be good.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #8 ·
Ah, yes, a story . . . I'd love to share! In a nutshell, I'm 80% confident it's the evap. I'm 95% certain the problem is behind the dash (doh).

So the quality of air conditioning was getting worse through the spring of last year. Fact is, I hadn't used the AC at all through the winter (for obvious reasons -- more on this later). I noticed that the driver's side of the car was getting more cool air than the other, this is one symptom people see when their E46s are running low on coolant. The AC hissed immediately after I turned it on for about 20 seconds. The hissing got longer and more noticeable as time past. I also noticed a new smell in the air, I can't describe it anymore (bummer). Turns out that was my refrigerant (well, freon isn't used anymore) escaping.

Finally, the AC just didn't cool well enough, and I had a mechanic recharge the refrigerant. He put some dye in there too, so that if there was a leak, he could have a fighting chance of finding it. As expected, the AC worked great for about a week. I could already smell the same weird smell I had sensed before. Shucks. Sure enough after a week or so, the same symptoms from above started showing up: Uneven cooling, hissing, smell. Back to the shop, maybe he'll find the leak in the engine bay . . .

Nope, he comes back and says he can't find the leak at all. And he wants $2k to replace the evaporator. I laugh and say, "Thanks, but no thanks". I've got a buddy who's a mechanic at a BMW dealership, and I talk it over with him. He explains that the evaporator cores on nearly every other body styles are bulletproof (They are! My E36's AC still works great 12 years out) but there's something about how the manufacturer built the E46 evaporators that just wasn't right. It's based on this experience that I agreed with my buddy, it's probably the evaporator.

One interesting point I gleaned while reading lots of posts online. Unrelated to BMWs, I found some people who recommend that, even in the winter, to run your AC every now and then. They explained that the refrigerant includes chemicals/oils that eat away at any rubber or seals in the system, and by not running the AC in the winter, this causes these chemicals to sit and eat away. Now, I'm a cheap son-of-a . . . so whenever my M3 tried to "automatically" turn on the AC when I activated defrost, I quickly turned off the AC. I'm starting to regret that. Heck, even if this advice was wrong, how much would it have cost me to run the AC once a week?

Too Long; Didn't Read? Cliff notes!

Symptoms of low refrigerant
  • Hissing when turning the AC on
  • Uneven cooling, driver's side is cooler than the passenger's side
  • A new smell when you turn the AC on

Use dye to help you find the leak, but if the dye doesn't tell you anything, it's hard to know what the problem is before you remove the dash. I'm told the evaporator core is a common E46 problem.
 

·
Registered
Joined
·
10,212 Posts
Remember who you're talking too. We want the long story! Thanks

I had the same deal with a '92 Lexus and the dealer charged $2000 and that was like 14 years ago.

Interesting to put the light on the evap, etc. when you open up the dash just to make sure you see exactly where the leak is. Please come back and describe as you progress.
Interesting that you say the e46 evaporators are a weak link as we've not heard of numbers of them being replaced. Now we're all hoping ours don't go too!

When you open this all up are you going to change out the evap & dryer? And then take it to a shop for vacuum and charge?


BTW, I think it's still Freon. Just R-134a instead of good old R-12.
 

·
Registered
Joined
·
10,212 Posts
Actually Freon is Dupont's trademark name for R-12
Probably more true than not, but think of Jello.
Freon is DuPont's brand name for CFCs, HCFCs and related compounds. Other commercial names from around the world are Algofrene, Arcton, Asahiflon, Daiflon, Eskimo, FCC, Flon, Flugene, Forane, Fridohna, Frigen, Frigedohn, Genetron, Isceon, Isotron, Kaiser, Kaltron, Khladon, Ledon, Racon, and Ucon.

A chlorofluorocarbon (CFC) is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane. A common subclass are the hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon. The most common representative is dichlorodifluoromethane (R-12 or Freon-12). Many CFCs have been widely used as refrigerants, propellants (in aerosol applications), and solvents. The manufacture of such compounds has been phased out by the Montreal Protocol because they contribute to ozone depletion.
 

·
Registered
Joined
·
301 Posts
Probably more true than not, but think of Jello.
Freon is DuPont's brand name for CFCs, HCFCs and related compounds. Other commercial names from around the world are Algofrene, Arcton, Asahiflon, Daiflon, Eskimo, FCC, Flon, Flugene, Forane, Fridohna, Frigen, Frigedohn, Genetron, Isceon, Isotron, Kaiser, Kaltron, Khladon, Ledon, Racon, and Ucon.

A chlorofluorocarbon (CFC) is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane. A common subclass are the hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon. The most common representative is dichlorodifluoromethane (R-12 or Freon-12). Many CFCs have been widely used as refrigerants, propellants (in aerosol applications), and solvents. The manufacture of such compounds has been phased out by the Montreal Protocol because they contribute to ozone depletion.
Sorry I mentioned it. LOL
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #14 ·
Hah, agreed. Wow, I opened up a can of worms trying to be syntactically correct. So, about that Evaporator . . . Any suggestions on after market for the drier, expansion valve, or heater core?
 
1 - 16 of 16 Posts
Top