90 240sx Hatch S13. Strange Heater and AC operations. INTERMITTENT if at all.

[RamonetB]

Hello all.

I've done some searches on these topics and while I have some ideas on how to approach this now, none of the posts describe exactly what's going on.

Essentially, heater was not giving off any real heat. I wasn't getting cold air, but more of a lukewarm mixture. Recently, I noticed I was leaking Coolant. So, I replaced the thermostat and gaskets, topped her off with collant (bleeding it, etc) and started her up. I got FABULOUS heat! For almost an hour.

Now things have gone back they way they were before replacing the thermostat. However, there is one new oddity. With the heater lever in the hot position, I get warm air. If I slide it down to cold and then immediately back up to warm, I get hot air (but not as hot as in the previous paragraph) for about 15 minutes before it disappears again.

Is this a result of some air getting into the coolant system?? Or the mixture door? A thermal sensor somewhere? The changing from floor to defrost, etc is sluggish. No clicking noises as if the motor is bad. Just the sound as if something needs to be lubed, reminiscent of the squeaky sound tupperware makes.

As and aside, the AC compressor doesn't turn on anymore, at least reliably. It worked when I started driving back home yesterday, but not anymore again. The light on the AC button turns on, but the AC itself doesn't turn on. This seems to be an intermittent problem. I'm hoping its electrical, as I haven't check the continuity or voltage on anything yet. I guess I'm asking for a heads up on where to look for this one / where to begin my search. I don't want to replace the compressor. I've still got the R-12 and loving it. Well... LOVED it..

Thanks everybody. I'll be sure to post solutions once I find them.

-kirk
Modified by RamonetB at 8:22 PM 4/13/2006

[ricebike]

i believe you still have a leak? or there's air still in the cooling system... rebleed the system to make sure...

as far as the mixture door; i don't have any problems w/ mines (1989) seems a bit sluggish as well...

AC part; you may be running low on refrigerant.I wouldn't know where to source one out since everywhere you look, it's all about 134A...

the compressor won't engage if it's low on refrigerant...

[RamonetB]

Well, went back and bled the coolant system again. Seems to be stable for now. Not getting intermittent heat. But I haven't been out on the road up at 75 mph yet. We'll test that this weekend.

As for the AC, an UPDATE.

The system is adequatly charged at 24 PSI. What type of coolant is in there, I'm now not sure. I assume it's still R12 as there are no stickers indicating a change. However, the nipple on the low end pipe fits the stock Wal-Mart 134A pressure gauge, not that it's an idication of anything....

Anyway, if I turn the key to just give power to the car (ACC I believe) I can press the AC button and the clutch engages on the compressor. You can hear it and see it. However, this doesn't always happen. Sometimes, NOTHING happens. You press the button and the clutch doesn't engaged (this is still with the engine off). In addition, sometimes the green light on the AC switch doesn't come on unless I hold it in. Sometimes it comes on and goes off. Whether the light is on or off doesn't seem to be an indication of the clutch on the compressor engaging.

One last thing, when the clutch does engaged and the engine is on, there is a noticable whine coming from the spinning of pully on the compressor. It doesn't sound like metal on metal, more like a fan that could use a lube. Not sure if this is normal or not as I've never paid attention to a compressor operating with the hood up before.

Perhaps it's the climate control or the relay? I'll do some more hunting around on the forums for this one. But, I thought I'd post an update.

Thanks guys.

-kirk

[ricebike]

...What type of refrigerant is in there, I'm now not sure. I assume it's still R12 as there are no stickers indicating a change. However, the nipple on the low end pipe fits the stock Wal-Mart 134A pressure gauge, not that it's an idication of anything....

I got one of them walmart 134A pressure gauge when i got a retrofit/recharging kit for wifey's car... I know for a fact that it shouldn't fit on an R12-equipped system.

The R12 access ports should be smaller than the R134A ones... so who knows what's in there... may have to bring this in & have it professionally evacuated & the refrigerant tested to see...

may need more internal lubrication as well, but the professional should check to see how much oil is inside the system & see...

[RamonetB]

Thanks Ricebike.

As usual, the community here is stellar. Hard to find good forums anymore.

One more stupid question,

With the car off, should I be able to move the AC Condensor fan by hand?

-kirk

P.S. Yes, refrigent vs coolant. My mistake. And yes, I do know what they say about assuming things.

[benemorius]

Several things I would like to note. First and foremost, I would like you to be aware that any anger or hostility you may sense from me henceforth is NOT intended to be directed at you but rather at Interdynamics.

If the 134a gauge fit on your service port, then be assured that you do not have r12. God only knows what the hell may be in there, but almost certainly it is anything but r12.

If you are concluding that your system has the correct amount of refrigerant based on your findings with one of these Inderdynamics DIY gauges, then I implore you to instead conclude that you have no ****ing clue how much refrigerant or oil (or water) is in your system.

If you're sure that the noisyness is coming from the a/c compressor and not simply from a belt, I would not honestly be surprised. There is no telling what kind of oil is in your system, nor how much oil, nor what condition the oil is in.

I'm going to have to cut this post short. I just got a morbidly disturbing phone call and suddenly I don't give a **** about you or your a/c.