Hey,

So my 95 dx is gonna hit 100k today! I love this car! Anyway I have an issue with the ac......it blows kinda cool but not ice cold even on max ac!?!? Last year I added one can of freeon, and if my memory serves me correctly it was the same then as it is now. So my questions are:

1.How can it blow colder?
2. How many cans of freeon does it need?
3.Any other thoughts/comments as what it could be?

 

Total capacity, starting from completely empty, is about 18 oz. That's of course only one and a half cans. Adding a whole can at a time when it still cools some, is probably overfilling it.

It should hold a charge for years. There is a leak. When you unscrew the cap, does it look green or yellow in there? If so there is UV dye in the system and someone with a UV lamp could look for it and find the leak. If not, you should add UV dye so then there is something to look for.

Charging by yourself with those little hoses that only go on one port is not recommended because it is easy to overcharge. You should buy a professional type gauge manifold that has two gauges, which lets you diagnose if the problem is really a low charge and also watch the high pressure while charging.

Absolutely do not use "stop leak." It doesn't stop leaks. It just ruins systems. Plain R134a and UV dye only.

 

werd.....thanks for the info!

 

i have a 95 Dx as well and i just ripped that ****n **** out of my car...i needed a new copressor so i said screw it it saves weight[sm=bounceybounce.gif]

 

I'm going through the same deal with my '95 VX. While it's running, check the high-side valve (the beige one) temperature - if it's hot to the touch (be careful), then what's going on is the expansion valve is most likely giving up the ghost. When the system is working properly, the refrigerant boils in the evaporator - which as it cools, almost freezes the air that's being blown through it. With the proper charge in the system, and the valve working properly, the evaporator cools the air with a normal amount of condensation that drains onto the ground through the drain hose through the firewall. If it cools too much, the condensation will freeze, clog the fins, and no air will pass through. Not enough, and you're having warm air issues. Lots of things can affect this: too much/too little refrigerant, bad expansion valve, bad compressor, clogged evaporator, clogged lines, clogged or broken condensor (that radiator-looking thingie), and a bad expansion valve/orfice tube.

If the expansion valve is not opening, then the freezing thing will happen. If it's not closing all the way, then the refrigerant won't do it's job no matter how much you put in (like mine is doing... and most likely yours too).

Your best bet is to take the car to a shop with a qualified A/C technician. If you can't afford to have him replace the expansion valve, then see if he'll evacuate the refrigerant from the system and do it yourself.

The expansion valve is not too expensive (between $30 and $40 at most auto parts stores) and not too much of a PITA to change. I just pulled mine out today and replaced it, but I have to wait until my pal's shop opens tomorrow to recharge the system and see if it worked.

To pull the expansion valve, disconnect and remove the battery, pull the battery tray, and you'll notice the A/C manifold on the firewall - disconnect it (BUT ONLY IF THE SYSTEM HAS BEEN EVACUATED!!). Remove the glove box, and then pull out the evaporator housing (the main housing closest to the center of the car) being careful around the SRS wiring. Once the evaporator housing is out of the car, split the housing open (remove clips and screws, and carefully cut the insulation at the seams), then carefully pull out the styrofoam insulation along with the evaporator itself. The expansion valve has three fittings with O-rings - be careful removing them so you don't bend the fins on the evaporator or bend the lines. Push some low-pressure air through the evaporator lines to remove any clogs that might be present (if something icky comes out, be prepared to get a new evaporator along with some more A/C components and lines, just in case). Put the new expansion valve in with the new O-rings, blow out the dust and whatnot from the fins and put it all back together - blow the dust and stuff off either before or after you remove the valve, being careful to not get any trash in the evaporator itself. Then reinstall the evaporator housing back into the car, reconnect the evaporator manifold, reinstall the battery tray and battery, put the glove box back in, reprogram your stereo, then head back to the shop that evacuated the refrigerant for you.

The technician will place your system under vacuum for at least 15 minutes - have him do it for 30 minutes. This will check to see if you have any leaks. If it holds steady for 30 minutes, then it should be leak-free. Then he'll recharge the system, and with any luck you'll have cold air again.

Having the system overcharged is dangerous because the high-side pressures can push over 450 psi!!! Normal operating pressures are usually between 150 and 230 psi - so get that checked out soon. And again - you should take it to a qualified A/C technician to safely evacuate the system before taking on any repairs yourself.

This concludes today's public service announcement about automotive A/C systems.

 

UPDATE: The expansion valve kinda solved my problem, as far as the A/C system doing what it's supposed to do, that is.

Unfortunately, the vents are not blowing cold air yet. They are, however, blowing much cooler air, and the A/C lines under the hood are sweating and heating in the proper places, so it's working properly. The rest of the problem, my best guess, is what's called the 'blend door' on most other cars. Honda calls it something different, but essentially it's the mechanism that reacts when you move the temperature control slider. According to All-Data, the cable is very touchy and becomes either dislodged or out of adjustment when disturbed. The 'blend door' closes off or opens up the flow of hot water through the heater core. Consequently, the heating is all done after the air has blown across the evaporator (which is ice cold while the A/C is on), causing the already chilled air to heat back up. If it's stuck open, then the heater is effectively still 'on' while the A/C is trying to chill the air - and you have lukewarm or warmer air from the vents. If it's stuck closed, then the heater will never heat up, no matter how hot the car gets.

The previous owner installed a nice in-dash AM/FM/CD head unit, and it appears that the temperature slider no longer enjoys the full range of movement to the 'heat' side. So, I'm guessing once I pull the dash panels, I'll discover this cable is no longer working properly and might get lucky with only having to adjust it to move the 'blend door' properly.

Wish me luck, I'll post what I find.

 

Good advice from Type RB. Couple of points though, first there is an electronic control that detects evaporator temperature to keep it from overcooling and freezing. Expansion valves do not regulate to any particular temperature, they simply optimize the refrigerant flow for best operation at the temperature they sense. If the system has enough capacity, the evaporator will freeze even with a properly functioning expansion valve. Thus the temperature control unit, which consists of a thermistor in the evaporator core linked to a little box on top of the evaporator case.

Reheating is a very common problem because the water valve isn't closing fully. The water valve is on the firewall in the engine compartment next to the vapor (evap emissions control) canister. It is linked by a cable to a lever on the bottom of the heater box. Then there is another cable from this lever system to the temperature control lever. You can see the linkage system by getting on your back under the driver's side of the dash (my favorite car repair position) and looking up.

In most cases if the temperature control lever is moving properly, you can just go under the hood and unclip the outer housing of the cable at the water valve and pull it out some and reclip it. That makes the valve move more toward closed with the temperature lever on full cold. It should not be possible to push the valve lever farther while the dash lever is at full cold.

 

Thanks for the low-down on the cable situation, mk378. I haven't been under there yet - waiting for my 5-day vacation (starting on the 4th) to get freaky with it. All-Data's diagrams are less than helpful without any visual references of familiar components - like maybe a steering column or something.

I'm of the opinion that the cable is way out of adjustment because I'm getting much warmer than ambient air through the vents with just fresh air (no A/C) blowing. Additionally, the lever on the dash doesn't have its full range of motion either - it stops about a half inch short of the 'hot' side when slid that direction. Should be fun though.

Any idea where the A/C idle-control signal originates and interfaces with the fuel system? Through the ECU, or independent circuit? I'm not sure if it was functioning before I got the car (it had a blown head-gasket and wasn't running when I snagged it), but it's definitely not working now. I'm going to attempt to troubleshoot that one as well.

 

It goes thru the ECU. When the A/C circuit calls for the compressor to engage, it drives an input to the ECU. The ECU increases the idle and about 0.5 second later the ECU drives an output to the compressor relay. So if your compressor is engaging, the ECU definitely knows about it because the signal passed thru it. Unless someone rewired something. Anything is possible of course with a used car.

 

OK - pulled the lower dash panel on the driver side, and discovered all of the 'vent control' cables and linkages were on that side. Then I pulled the glove box door and discovered the 'blend door' cable, and yes - it was out of adjustment. Pulled the temp slider all the way to 'cool,' popped the cable out of it's cheesy little bracket, closed the blend door, and reinstalled the cable. Now the temp slider has full range of motion, and I have cold air coming through the vents with the A/C running.

I can't believe how poorly designed the temperature cable and mechanism is. Oh well - easy enough to fix if/when it needs it.

Now I just need to figure out why the A/C signal is not working properly. I had to set the idle to 750 while the A/C was running (to keep the compressor from cycling on and off every second), and consequently, the idle when the A/C is off is just over 1300. I can live with it, but it's still not right.