[webowser]

While crossing New Mexico last Tuesday in my 2005 Elise some A/C system component under the dash ruptured which allowed all the refrigerant to escape in just a few seconds. The vapor spewed out of the vents while I scrambled to turn off the A/C and open the windows. From then on the trip back to Cincinnati was rather uncomfortable for me and my golden retriever.

I figure I'll take the car apart to see what happened, but before I do I need some advise about how to access the evaporator coil, and what you guys think I might find.

Thanks,
Bill

 

[SirLotus]

Hi Bill,
You can see the evaporator by removing the main air distribution duct under the center hood spline, see photo 7 & 9 here http://www.lotustalk.com/forums/f92/improved-c-heating-system-71031/ unless it is obvious, a leak check will have to be done. That location seems like a good possibility as a leak there would be be blown into the vent distribution system.
Michael

 

[webowser]

Thanks Michael,

Actually I had taken a look at those pictures a few minutes ago, and I planned to remove the panels to see what I can see. If I can remove the evaporator coil from the exterior I suspect I'll discover the problem. (I'm hoping I don't have to remove the dash.) I suspect a connection to the evaporator coil has broken, but I could be way off.

Bill

 

[SirLotus]

Bill
I suspect that any work in that area may be a clam off job
Michael

Thanks Michael,

Actually I had taken a look at those pictures a few minutes ago, and I planned to remove the panels to see what I can see. If I can remove the evaporator coil from the exterior I suspect I'll discover the problem. (I'm hoping I don't have to remove the dash.) I suspect a connection to the evaporator coil has broken, but I could be way off.

Bill

 

[webowser]

I wish you hadn't said that; I was really hoping I wouldn't have to remove the clam. Well, I guess I'll find out when I start taking it apart.

Bill

 

[SirLotus]

Good luck, Bill

I wish you hadn't said that; I was really hoping I wouldn't have to remove the clam. Well, I guess I'll find out when I start taaking it apart.

Bill

 

[JoshS]

While crossing New Mexico last Tuesday in my 2005 Elise some A/C system component under the dash ruptured which allowed all the refrigerant to escape in just a few seconds. The vapor spewed out of the vents while I scrambled to turn off the A/C and open the windows.Thanks,
Bill

Freon has no odor, but oil runs through the system along with the freon, that is probably what you smelled. Once you have access you can run any cheap gas through the system such as nitrogen (don't use oxygen unless you have a death wish) and get a bottle of soap suds and spray the coil and connections. Turning off the A/C will not stop the escape of freon(if a high side leak, you slowed it down, if it was a leak in the evaporator coil itself you sped the leak up) and it is not poisoness unless burned, and if that happened you'd be dead. So if your not dead, it didn't burn.

 

[webowser]

It wasn't a matter of smelling the refrigerant; I could see the vapor coming out of the vents. I could hear the gas escaping. It all blew out in a second or two. It was almost like an explosion. I turned it off because I knew it was dead. All the gas had escaped by the time I shut it off. (The compressor had stopped because the pressure switch dropped out.) I opened the windows to avoid breathing as much of the gas as possible.

I believe the leak would have to be on the liquid/high pressure side of the expansion valve at the evaporator coil. It is not going to take soap bubbles to find this leak. Something broke, and left a substantial hole. It is going to be apparent when I get it uncovered. It is as if a hose blew off, but I'm sure they're connected with threaded fittings. Other than the sound of the very rapid escape of gas there was no unusual noise. I hope I don't have to dismantle the whole car to find the problem.

Bill

 

[Dragon]

It wasn't a matter of smelling the refrigerant; I could see the vapor coming out of the vents. I could hear the gas escaping. It all blew out in a second or two. It was almost like an explosion. I turned it off because I knew it was dead. All the gas had escaped by the time I shut it off. (The compressor had stopped because the pressure switch dropped out.) I opened the windows to avoid breathing as much of the gas as possible.

I believe the leak would have to be on the liquid/high pressure side of the expansion valve at the evaporator coil. It is not going to take soap bubbles to find this leak. Something broke, and left a substantial hole. It is going to be apparent when I get it uncovered. It is as if a hose blew off, but I'm sure they're connected with threaded fittings. Other than the sound of the very rapid escape of gas there was no unusual noise. I hope I don't have to dismantle the whole car to find the problem.

Bill

You will have to remove the whole front end and a whole lot more to get it out and replaced... I had to fix my blower fan recently . I would recommend that when you fix the evaporator you do the resistor upgrade for the blower fan, SS brake lines and 3 pass radiator at the same time so you'll hopefully never have to go in to that area again in the future....

 

[JoshS]

. I turned it off because I knew it was dead. All the gas had escaped by the time I shut it off. (The compressor had stopped because the pressure switch dropped out.) I opened the windows to avoid breathing as much of the gas as possible.

Bill

I was semi joking with you, when you said you scrambled to turn the A/C off I thought you were worried about breathing in the vapor. It could make you dizzy because it displaces oxygen, but it is inert otherwise. My guess is you did blow the tubing out at a fitting, and if you can get at it it might be a very easy fix. Sounds like they didn't flare the tubing enough.

 

[SirLotus]

Bill,
Here is a close up of the 2 pipes going into the expansion valve. I suspect however, that the failure was at the evaporator because the gas was blown through the vents which probably would not have happened if the leak was on the outside of the HVAC enclosure.
Michael

 

[webowser]

Well, I discovered the problem. On top of the expansion valve there is a clamp plate which holds the liquid and gas tubes in place on the expansion valve. The clamp plate is attached with one socket head cap screw. (These items can be seen in the picture that Viper included in the previous post.) The clamp plate screw came loose and allowed the tubes to blow out of the expansion valve. When I get it a little more accessible I'll take some photos and post them if I can remember how to do it.

Now I'm wondering how the vapor came out of the vents with the leak being outside the HVAC enclosure. I'll continue to investigate. Tomorrow I plan to remove the front clam and see what I can find out.

Thanks for you help guys,
Bill

 

[QuadCamSix]

Bill,

The exact same thing happened to me a little over a week ago! I have not had a chance to investigate yet but the oil from the AC system actually made it all the way to windshield vents! Good thing its really light weight oil! Please post your AC system post mortem. It would be great to know what I'm after. Im betting this is a common failure mode that hasn't really been investigated on the board yet.

 

[webowser]

Well the front clam has been removed. It took about two hours, and wasn't really difficult. Some fasteners are difficult to get to, but I expected that.

Regarding the A/C leak What I thought might be a relatively easy fix after I gained access to the expansion valve is proving to be somewhat more difficult. The clamp plate screw broke. (No wonder all the gas leaked out so quickly.) The break is flush with the top surface of the expansion valve. I'll have to drill a hole in it and see if an easy-out will remove it. I should get some pictures later today.

Bill in Cincinnati

 

[SirLotus]

Glad you found it Bill. My guess is that there is negative pressure in the system which sucked the gas in, as it is not sealed very well ( check the way the main duct just pushes on.) BTW, this would be a great opportunity to insulate in that area to improve the AC performance.
Michael

 

[Valenz]

Since your system has been open to air for some time now, you'll want to be sure and flush the old oil out of the system and replace it. The oil used by Lotus for their 134a system is PAG (polyalkylene glycol) oil that is rather hygroscopic (it absorbs moisture from the air). The moisture that becomes trapped in the oil will release acid into your refrigerant lines. This acid will cause no end of corrosion problems with your compressor, expansion valve and the aluminum tubing in the system (that's one reason why the dryer in these systems is so important - oh, btw, the dryer will also need to be replaced.) You can replace the oil with a similar PAG, POE (polyolester) or any ester-based oil, but it is also possible to run a 134a system with an alkylbenzene oil (that is not hygroscopic). Note however that you CANNOT use mineral oil with a 134a refrigerant system.

Most of the 'vapor' that you saw discharged into your car when the failure occured was the oil mist that circulates with the refrigerant. You and your dog should not have any problems with squeeky lungs now.

Good luck!

A.J.

 

[JoshS]

Most of the 'vapor' that you saw discharged into your car when the failure occured was the oil mist that circulates with the refrigerant. You and your dog should not have any problems with squeeky lungs now.

Good luck!

A.J.

SHHHHH! DOn't tell him that, I got my head handed to me on a platter for suggesting the Vapor was oil.

 

[webowser]

Thanks A.J. When I have everything back together I plan to have a professional evacuate, leak test, and recharge the system. I'll discuss the oil and the dryer with him.

Well, I have lucked out. It turns out that the expansion valve is easily removed from the car, and once removed the broken screw was easily extracted. So now I need to get a replacement screw and I put the A/C plumbing back together.

I took a few photos, but I don't know how to post them, so if someone doesn't tell me how to do it then you guys who want to see what I've been talking about are out of luck.

Bill in Cincinnati

 

[SirLotus]

Bill, looking forward to seeing the pics. Scroll down until you see "manage attachments", files from your computer have to be under 1000 kb to upload.
Michael

 

[Valenz]

SHHHHH! Don't tell him that, I got my head handed to me on a platter for suggesting the Vapor was oil.

I'm not familiar with that incident. The objection may have been the improper use of the term 'vapor.' Strickly defined, a vapor is the gaseous state of a substance that is liquid or solid under ordinary conditions. Hence a vapor is not visible except perhaps by virtue of a difference in the index of refraction relative to air (like the hot air schlering that one sees immediately above a very hot surface). Small finely dispersed particles or droplets suspended in the air (which usually appear white or opaque as opposed to clear and transparent) are more properly termed a 'mist.' This holds true for everything except water where a special term is introduced for water in the gaseous state - 'steam.' In the case of water, 'water vapor' is the term used to describe what is actually a 'mist' - finely suspended droplets. That white stuff that you see bellowing out of a tea kettle or coffee pot is actually 'water vapor'. Steam, if you look carefully, is the very hot colorless transparent gas that you see only right as the hot gaseous water exits the vessel. As soon as steam expands and cools you get droplet formation and a white 'mist' that is properly called 'water vapor.' Clouds are formed of 'water vapor' not steam. Only with water is it appropriate to refer to the milky mist as 'water vapor' and that's because of the availability of the special term 'steam' for gaseous water. For all other substances, the vapor state is transparent and not a suspension or mist. Technically speaking.