AC issue

Have a question on the ac system on the Miata. Have a 90 with r12.
Took it in and the pressure is good and has the correct amount of
freon. But after 20-30 minutes of driving it stops working and starts
to blow hot air, but then will come back on after a few minutes.
Also, sometimes the rpms goes up to over 1500 to 2000 while at idle,
stopped at a red light and such. Any ideas? Finding it hard to take
it to a place that I trust and want to be able to go in and at least
have some idea what might be wrong. Thanks.

Mac > wrote:

> Have a question on the ac system on the Miata. Have a 90 with
> r12. Took it in and the pressure is good and has the correct
> amount of freon. But after 20-30 minutes of driving it stops
> working and starts to blow hot air, but then will come back on
> after a few minutes. Also, sometimes the rpms goes up to over 1500
> to 2000 while at idle, stopped at a red light and such. Any
> ideas? Finding it hard to take it to a place that I trust and
> want to be able to go in and at least have some idea what might be
> wrong.

I've no idea, I have the same AC problem but not the idle speed problem
on my Jeep. Could possibly be known problem on the '93 Grand Cherokee,
the computer fails to send a signal to turn off the compressor when it
should and the unit ices up. I doubt there's anything similar on the
Miata but who knows?

I also had a similar problem on the Miata two years ago, AC was cooling
just fine and then started blowing hot, like the compressor was turned
off. Next time I drove, same thing, no AC.

I suspected low freon causing the pressure switch to stop the
compressor. I took it in and they said it wasn't leaking but added a
can of dye.

A few days later, it stopped again but when I stopped the car it worked
when I started it again and...... it's never failed since! Go figure.
BTW, the dye showed no leaks.

I really doubt any of the above will help you any, sorry. Isn't there
anyone you know that can recommend a shop? That's probably the best
way to find a good one....



--
XS11E, Killing all posts from Google Groups
The Usenet Improvement Project: http://blinkynet.net/comp/uip5.html

I've dealt with this issue on several cars. Each time it's been the same
thing; the drain on the reservoir that the ac dumps the humidity into, clogs
up and the reservoir gets full. AC quits working. Often times (but not
always) combined with soaking the carpets in the floorboards from
'sloshing'.

Try this; car up on jack stands, running, ac on, (assuming it's not
working), try running a wire up thru the drain hose from under the car. You
know, the one that normally drips when the ac is running. Often times you'll
be able to nudge some debris out of the way and the water will come rushing
out (smelling like you-know-what! If this works, at least you've identified
the problem. I haven't removed this and cleaned it out on a miata. Some cars
it's easy, others, it's a royal pain. Alternative; try to suck the debris
out with a shop vac and some creative hose adapters ;-)

Keep us posted,
Chris
99BBB

"XS11E" > wrote in message
. 184...
> Mac > wrote:
>
>> Have a question on the ac system on the Miata. Have a 90 with
>> r12. Took it in and the pressure is good and has the correct
>> amount of freon. But after 20-30 minutes of driving it stops
>> working and starts to blow hot air, but then will come back on
>> after a few minutes. Also, sometimes the rpms goes up to over 1500
>> to 2000 while at idle, stopped at a red light and such. Any
>> ideas? Finding it hard to take it to a place that I trust and
>> want to be able to go in and at least have some idea what might be
>> wrong.
>
> I've no idea, I have the same AC problem but not the idle speed problem
> on my Jeep. Could possibly be known problem on the '93 Grand Cherokee,
> the computer fails to send a signal to turn off the compressor when it
> should and the unit ices up. I doubt there's anything similar on the
> Miata but who knows?
>
> I also had a similar problem on the Miata two years ago, AC was cooling
> just fine and then started blowing hot, like the compressor was turned
> off. Next time I drove, same thing, no AC.
>
> I suspected low freon causing the pressure switch to stop the
> compressor. I took it in and they said it wasn't leaking but added a
> can of dye.
>
> A few days later, it stopped again but when I stopped the car it worked
> when I started it again and...... it's never failed since! Go figure.
> BTW, the dye showed no leaks.
>
> I really doubt any of the above will help you any, sorry. Isn't there
> anyone you know that can recommend a shop? That's probably the best
> way to find a good one....
>
>
>
> --
> XS11E, Killing all posts from Google Groups
> The Usenet Improvement Project: http://blinkynet.net/comp/uip5.html

Just for my general knowledge: where is this drain situated? I guess it runs
from the evaporator to ???

Jeroen
MX-5 Club Netherlands

"Chris D'Agnolo" > schreef in bericht
...
| I've dealt with this issue on several cars. Each time it's been the same
| thing; the drain on the reservoir that the ac dumps the humidity into,
clogs
| up and the reservoir gets full. AC quits working. Often times (but not
| always) combined with soaking the carpets in the floorboards from
| 'sloshing'.
|
| Try this; car up on jack stands, running, ac on, (assuming it's not
| working), try running a wire up thru the drain hose from under the car.
You
| know, the one that normally drips when the ac is running. Often times
you'll
| be able to nudge some debris out of the way and the water will come
rushing
| out (smelling like you-know-what! If this works, at least you've
identified
| the problem. I haven't removed this and cleaned it out on a miata. Some
cars
| it's easy, others, it's a royal pain. Alternative; try to suck the debris
| out with a shop vac and some creative hose adapters ;-)
|
| Keep us posted,
| Chris
| 99BBB
|
| "XS11E" > wrote in message
| . 184...
| > Mac > wrote:
| >
| >> Have a question on the ac system on the Miata. Have a 90 with
| >> r12. Took it in and the pressure is good and has the correct
| >> amount of freon. But after 20-30 minutes of driving it stops
| >> working and starts to blow hot air, but then will come back on
| >> after a few minutes. Also, sometimes the rpms goes up to over 1500
| >> to 2000 while at idle, stopped at a red light and such. Any
| >> ideas? Finding it hard to take it to a place that I trust and
| >> want to be able to go in and at least have some idea what might be
| >> wrong.
| >
| > I've no idea, I have the same AC problem but not the idle speed problem
| > on my Jeep. Could possibly be known problem on the '93 Grand Cherokee,
| > the computer fails to send a signal to turn off the compressor when it
| > should and the unit ices up. I doubt there's anything similar on the
| > Miata but who knows?
| >
| > I also had a similar problem on the Miata two years ago, AC was cooling
| > just fine and then started blowing hot, like the compressor was turned
| > off. Next time I drove, same thing, no AC.
| >
| > I suspected low freon causing the pressure switch to stop the
| > compressor. I took it in and they said it wasn't leaking but added a
| > can of dye.
| >
| > A few days later, it stopped again but when I stopped the car it worked
| > when I started it again and...... it's never failed since! Go figure.
| > BTW, the dye showed no leaks.
| >
| > I really doubt any of the above will help you any, sorry. Isn't there
| > anyone you know that can recommend a shop? That's probably the best
| > way to find a good one....
| >
| >
| >
| > --
| > XS11E, Killing all posts from Google Groups
| > The Usenet Improvement Project: http://blinkynet.net/comp/uip5.html
|
|

Checked the drain and is it clear. Even took the hose off and checked
it. Hose is located under the passenger side dash. will see it
coming out of the evaporator. Ran the car for 15-20 minutes and the
ac stayed on the whole time. Should it cycle on/off and if so how
many times is normal or does it stay on all the time??? Does not
seem like it is cycling right.



On Sun, 24 Jun 2007 01:14:13 +0200, "Jeroen Feelders"
<http://mailto.feelders.com> wrote:

>Just for my general knowledge: where is this drain situated? I guess it runs
>from the evaporator to ???
>
>Jeroen
>MX-5 Club Netherlands
>
>"Chris D'Agnolo" > schreef in bericht
.. .
>| I've dealt with this issue on several cars. Each time it's been the same
>| thing; the drain on the reservoir that the ac dumps the humidity into,
>clogs
>| up and the reservoir gets full. AC quits working. Often times (but not
>| always) combined with soaking the carpets in the floorboards from
>| 'sloshing'.
>|
>| Try this; car up on jack stands, running, ac on, (assuming it's not
>| working), try running a wire up thru the drain hose from under the car.
>You
>| know, the one that normally drips when the ac is running. Often times
>you'll
>| be able to nudge some debris out of the way and the water will come
>rushing
>| out (smelling like you-know-what! If this works, at least you've
>identified
>| the problem. I haven't removed this and cleaned it out on a miata. Some
>cars
>| it's easy, others, it's a royal pain. Alternative; try to suck the debris
>| out with a shop vac and some creative hose adapters ;-)
>|
>| Keep us posted,
>| Chris
>| 99BBB
>|
>| "XS11E" > wrote in message
>| . 184...
>| > Mac > wrote:
>| >
>| >> Have a question on the ac system on the Miata. Have a 90 with
>| >> r12. Took it in and the pressure is good and has the correct
>| >> amount of freon. But after 20-30 minutes of driving it stops
>| >> working and starts to blow hot air, but then will come back on
>| >> after a few minutes. Also, sometimes the rpms goes up to over 1500
>| >> to 2000 while at idle, stopped at a red light and such. Any
>| >> ideas? Finding it hard to take it to a place that I trust and
>| >> want to be able to go in and at least have some idea what might be
>| >> wrong.
>| >
>| > I've no idea, I have the same AC problem but not the idle speed problem
>| > on my Jeep. Could possibly be known problem on the '93 Grand Cherokee,
>| > the computer fails to send a signal to turn off the compressor when it
>| > should and the unit ices up. I doubt there's anything similar on the
>| > Miata but who knows?
>| >
>| > I also had a similar problem on the Miata two years ago, AC was cooling
>| > just fine and then started blowing hot, like the compressor was turned
>| > off. Next time I drove, same thing, no AC.
>| >
>| > I suspected low freon causing the pressure switch to stop the
>| > compressor. I took it in and they said it wasn't leaking but added a
>| > can of dye.
>| >
>| > A few days later, it stopped again but when I stopped the car it worked
>| > when I started it again and...... it's never failed since! Go figure.
>| > BTW, the dye showed no leaks.
>| >
>| > I really doubt any of the above will help you any, sorry. Isn't there
>| > anyone you know that can recommend a shop? That's probably the best
>| > way to find a good one....
>| >
>| >
>| >
>| > --
>| > XS11E, Killing all posts from Google Groups
>| > The Usenet Improvement Project: http://blinkynet.net/comp/uip5.html
>|
>|
>

"Jeroen Feelders" <http://mailto.feelders.com> wrote:

>Just for my general knowledge: where is this drain situated? I guess it runs
>from the evaporator to ???

I guess you still don't have many AC in the Netherlands. There is a short
rubber hose that runs from behind the glove compartment to the transmission
tunnel, passenger side of course. People with NA cars with AC get used to
finding water on the floor at the passenger side and taking out the hose to
unclog the exit of the evaporator enclosure behind the glove compartment
by poking with a screwdriver.

Leon

>Jeroen
>MX-5 Club Netherlands
>
>"Chris D'Agnolo" > schreef in bericht
.. .
>| I've dealt with this issue on several cars. Each time it's been the same
>| thing; the drain on the reservoir that the ac dumps the humidity into,
>clogs
>| up and the reservoir gets full. AC quits working. Often times (but not
>| always) combined with soaking the carpets in the floorboards from
>| 'sloshing'.
>|
>| Try this; car up on jack stands, running, ac on, (assuming it's not
>| working), try running a wire up thru the drain hose from under the car.
>You
>| know, the one that normally drips when the ac is running. Often times
>you'll
>| be able to nudge some debris out of the way and the water will come
>rushing
>| out (smelling like you-know-what! If this works, at least you've
>identified
>| the problem. I haven't removed this and cleaned it out on a miata. Some
>cars
>| it's easy, others, it's a royal pain. Alternative; try to suck the debris
>| out with a shop vac and some creative hose adapters ;-)
>|
>| Keep us posted,
>| Chris
>| 99BBB
>|
>| "XS11E" > wrote in message
>| . 184...
>| > Mac > wrote:
>| >
>| >> Have a question on the ac system on the Miata. Have a 90 with
>| >> r12. Took it in and the pressure is good and has the correct
>| >> amount of freon. But after 20-30 minutes of driving it stops
>| >> working and starts to blow hot air, but then will come back on
>| >> after a few minutes. Also, sometimes the rpms goes up to over 1500
>| >> to 2000 while at idle, stopped at a red light and such. Any
>| >> ideas? Finding it hard to take it to a place that I trust and
>| >> want to be able to go in and at least have some idea what might be
>| >> wrong.
>| >
>| > I've no idea, I have the same AC problem but not the idle speed problem
>| > on my Jeep. Could possibly be known problem on the '93 Grand Cherokee,
>| > the computer fails to send a signal to turn off the compressor when it
>| > should and the unit ices up. I doubt there's anything similar on the
>| > Miata but who knows?
>| >
>| > I also had a similar problem on the Miata two years ago, AC was cooling
>| > just fine and then started blowing hot, like the compressor was turned
>| > off. Next time I drove, same thing, no AC.
>| >
>| > I suspected low freon causing the pressure switch to stop the
>| > compressor. I took it in and they said it wasn't leaking but added a
>| > can of dye.
>| >
>| > A few days later, it stopped again but when I stopped the car it worked
>| > when I started it again and...... it's never failed since! Go figure.
>| > BTW, the dye showed no leaks.
>| >
>| > I really doubt any of the above will help you any, sorry. Isn't there
>| > anyone you know that can recommend a shop? That's probably the best
>| > way to find a good one....
>| >
>| >
>| >
>| > --
>| > XS11E, Killing all posts from Google Groups
>| > The Usenet Improvement Project: http://blinkynet.net/comp/uip5.html
>|
>|
>
--
Leon van Dommelen Bess, the Miata Bozo, the Miata
http://www.dommelen.net/miata
The only thing better than a white Miata is two white Miatas

> People with NA cars with AC get used to
> finding water on the floor at the passenger side and taking out the hose
to
> unclog the exit of the evaporator enclosure behind the glove compartment
> by poking with a screwdriver.

I'm getting this right now except that I usually find the water on my dog,
who likes to curl up down there. I still get a little water out the hose
underneath, but apparently not all of it. A left turn seems to set off a
grand slosh that dumps a glassful or so all at once.

Are you saying the blockage is usually up in the under-dash unit rather than
in the hose? I was going to blow air up from underneath but it sounds like
taking the pipe off under the dash might be more useful.

miker

miker wrote:

>
> Are you saying the blockage is usually up in the under-dash unit rather than
> in the hose? I was going to blow air up from underneath but it sounds like
> taking the pipe off under the dash might be more useful.
>
> miker

On my last Miata, I removed the tube and poked a straightened coat
hanger wire into the box itself where I could feel it dislodging the
debris and then a lot of dirty water would come out, with some of it
even landing in the bucket I had in place.

I had to do this maybe 3 times over about 5 or 6 years. I could have
removed the box and cleared the debris, but that it a fairly involved job.

BTW, the drain tube itself was never blocked in my experience, it was
always the debris in the plastic box where the tube attaches, with this
car and on at least 3 other NA Miatas that I have unblocked.

Pat

"pws" > wrote in message
...
> miker wrote:
>
>>
>> Are you saying the blockage is usually up in the under-dash unit rather
>> than
>> in the hose? I was going to blow air up from underneath but it sounds
>> like
>> taking the pipe off under the dash might be more useful.
>>
>> miker
>
> On my last Miata, I removed the tube and poked a straightened coat hanger
> wire into the box itself where I could feel it dislodging the debris and
> then a lot of dirty water would come out, with some of it even landing in
> the bucket I had in place.
>
> I had to do this maybe 3 times over about 5 or 6 years. I could have
> removed the box and cleared the debris, but that it a fairly involved job.
>
> BTW, the drain tube itself was never blocked in my experience, it was
> always the debris in the plastic box where the tube attaches, with this
> car and on at least 3 other NA Miatas that I have unblocked.
>
> Pat

Going on 11 years for me. Haven't had a problem. Curious.

> On my last Miata, I removed the tube and poked a straightened coat
> hanger wire into the box itself where I could feel it dislodging the
> debris and then a lot of dirty water would come out, with some of it
> even landing in the bucket I had in place.

Ok, that was dead easy. Pull the tube off (no clamp or anything), poke a)
stubby screwdriver; b) section of coathanger; c) hex key up there... as you
say, I could feel almost a little crust I broke thru and water started
draining. I caught most of it with a towel before realizing I coulda just
put the dem tube back on.

miker