corolla 90 ac cools only at night

Messages
26
hello,

so i bought a new to me 1990 toyota corolla and the ac was ice cold. a month later that ac was warm. i took it to a ac repair shop where they told me that the system had leaks in the lines and the evaporator. the ac shop changed out the evaporator for a new one, new expansion valve, new drying air filter and new o rings in some lines. the shop also supposedly fixed a couple of leaks in the lines.

it was cooling all right when i picked her up from the ac shop.

two weeks later the ac cools at night time but during the hot day it does not cool. i took it to the ac repair shop again. it was probably 90 degrees fahrentit temperature for the morning and the best ac center vent temp measurement was 55 degrees fahrenheit.

the ac shop took some coil cleaner and cleaned the conderser coils. the ac center vent temperature dropped 5 degrees to 50 degrees fahrenheit after the condenser coil cleaning.

this car was originally r 22 so only has low pressure valve. the low pressure psi was 28 psi. the ac shop that that was good low side pressure as according to ac shop low side pressure is good between 30 and 45 psi.

ac shop says that to make car cool better that the condenser fan motor might have to be replaced, an electric auxiliary fan might have to be installed , including also perhaps a new condenser.

what stumps me is why when i bought the car the ac was ice cold?

i would imagine the guy who sold the car to me probably recharged the freon right before i went to see the car, but that doesnt explain that if there are no leaks why the car doesnt cool in the day like before when i bought it.

i dont know whether to follow the ac guys recommendations or take it to another ac shop to get a diagnostic and see if there is a freon leak still somehwere possibly.

wih outside temperatures at around 90 degrees fahrenheit. the center vent ac temp is 60 degrees fahrenheit. when under 2000 rpm perhaps at 90 degrees F outside temperature the center venct ac temp best is 50 degrees fahrentheit.

only at night when outside temperature is around 80 degress F does the ac center vent temp go down to 40 degrees Fahrenheit.

what to do?

thanks
 
Messages
12,475
Location
North Carolina
Originally r-22? That does not sound right.
I'd go to another shop. If your radiator fan is working, sounds like the refrigerant charge is not right.
 
Messages
1,306
Location
PEARL River la
28 is to low. Sounds like your evaporator will be freezing. Need to check high side temps as well. Either way you can have multiple problems such as bad valve, leaks, compressor etc. but without readings on both sides at 2k hard to tell. Need to go to another shop for ac specialist
Should be r12
 

somerandomguy1

Thread starter
Messages
26
28 is to low. Sounds like your evaporator will be freezing. Need to check high side temps as well. Either way you can have multiple problems such as bad valve, leaks, compressor etc. but without readings on both sides at 2k hard to tell. Need to go to another shop for ac specialist
Should be r12

the ac guy said something to the effect that the low side pressure temp was -2 degrees celsius. that is freezing. the car is original r12 so i would imagine there is no high side temp valve for checking. i would like to go another ac shop.
 

somerandomguy1

Thread starter
Messages
26
R12 not 22. Is the suction line cold? Is the heater valve letting hot water past and into the heater core?

the lines are cold in the engine bay. the ac guy said there was no heater function on the car.

There is a high side valve and part of the retrofit procedure is to put an r134a adapter on it.

ac guy says that car only has low side valve its a 90 toyota corolla
 
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2,987
Location
USA
They all had a high side port. It's either on the compressor or on the high side line near the firewall, or in some cases both.

By "no heater function" you mean the heater hoses are disconnected? If the heater is hooked up there will be a water valve on the firewall which is activated by a push-pull cable that eventually leads to the hot-cold lever on the dash. Check that the valve is pushed to full closed when the lever is at full cold. It is very common for the cable to need adjusting.
 
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3,043
Location
The Northeast
Was the car already switched over to R134a when you bought it? R12 and R134a take different oils and I'm wondering if that's the issue.

Sounds like your repair shop is firing the parts cannon on a 30 yr old car.
 
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Messages
1,625
Location
VA
How humid is it where you live? I notice my A/C doesn't feel as cool when the humidity is high. In dry air, it feels as cold as the day I picked up the truck in 2001. Also, I do mostly shorter trips around town, so the air is working to overcome heat soak for a lot of every trip.

I'm not qualified to say anything technical like the members above, but it does sound like something is marginal.
 

JC1

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5,533
Location
Oshawa, Ontario Canada
Was the car already switched over to R134a when you bought it? R12 and R134a take different oils and I'm wondering if that's the issue.

Sounds like your repair shop is firing the parts cannon on a 30 yr old car.

I'd hate to know how much he spent on a 30 year old corolla to get it fixed.
 
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21,856
Location
Apple Valley, California
I'd hate to know how much he spent on a 30 year old corolla to get it fixed.
People spend bug bucks at my shop to fix stuff. We get $300 to do a proper retrofit. Since we have no rust here cars last forever here. Not uncommon to spend $1k or more.

We did a major on a 94 taurus a few months ago. Cost $2400 which included pulling the dash. People figure a $2400 repair is less than a new car.
 
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21,856
Location
Apple Valley, California
As I said that car has a high pressure port somewhere unless it had a line replaced and they forgot to put one in. The ac shop will need to add one if that is the case.

Now----- AC CAN'T BE DIAGNOSED WITH NO HIGH SIDE READING. If the shop does not know that they are idiots. Take it somewhere else.
 
Messages
423
Location
Michigan
Isn't R22 what they were using in residential a/c central air units?? That's before they went with the cfc free version a couple years ago.. oh wait it was earlier this year that r22 was banned.. just checked..

wow.. so an automotive so-called "Technician" is calling it r-22 instead of what it is, r-12?! If they can't even name the correct refrigerant, if that's the case, RUN FAR FAR AWAY!!
 
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somerandomguy1

Thread starter
Messages
26
There is a high side valve and part of the retrofit procedure is to put an r134a adapter on it.

ac guy said that there is a r12 high side port but that the gauges dont fit on it to read the pressure so ac guy
recomended to cut old r12 high side valve and retrofit a new r134 high side valve so gauges can read high side
pressure.
They all had a high side port. It's either on the compressor or on the high side line near the firewall, or in some cases both.

By "no heater function" you mean the heater hoses are disconnected? If the heater is hooked up there will be a water valve on the firewall which is activated by a push-pull cable that eventually leads to the hot-cold lever on the dash. Check that the valve is pushed to full closed when the lever is at full cold. It is very common for the cable to need adjusting.

i will ask the ac guy if the heater hoses are removed.
Was the car already switched over to R134a when you bought it? R12 and R134a take different oils and I'm wondering if that's the issue.

Sounds like your repair shop is firing the parts cannon on a 30 yr old car.

i would imagine the car was already retrofitted to r134 since when i bought the car the salesman topped up the freon and r12 freon is note ven sold here and if it is it is way more expensive than r134.
How humid is it where you live? I notice my A/C doesn't feel as cool when the humidity is high. In dry air, it feels as cold as the day I picked up the truck in 2001. Also, I do mostly shorter trips around town, so the air is working to overcome heat soak for a lot of every trip.

I'm not qualified to say anything technical like the members above, but it does sound like something is marginal.

humidity is 90 percent where i live. thing is humidity was the same probably as today when i bought the car and the car was s ac was freezing cold when i bought it.
I'd hate to know how much he spent on a 30 year old corolla to get it fixed.

so far im in it for around 190 dollars on car ac.
As I said that car has a high pressure port somewhere unless it had a line replaced and they forgot to put one in. The ac shop will need to add one if that is the case.

Now----- AC CAN'T BE DIAGNOSED WITH NO HIGH SIDE READING. If the shop does not know that they are idiots. Take it somewhere else.

duly noted. thanks.
I don't recall any vehicle using R22 refrigerant. Best I can remember(I'm 84) we went from R12 to R134.

correct ac was r12 before
Isn't R22 what they were using in residential a/c central air units?? That's before they went with the cfc free version a couple years ago.. oh wait it was earlier this year that r22 was banned.. just checked..

wow.. so an automotive so-called "Technician" is calling it r-22 instead of what it is, r-12?! If they can't even name the correct refrigerant, if that's the case, RUN FAR FAR AWAY!!

sorry i didnt know the difference between r12 and r22.

second ac guy said low side valve center had leak. first ac guy says even if low side valve center has leak that
there is a cap on low side valve that doesnt allow leak.
 
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Messages
2,987
Location
USA
Your guy really doesn't know what he's doing. Find someone else. You don't have to cut anything to put an adapter on. Buy the proper adapter (there are two sizes of factory high side ports) and screw it on.

These systems weren't super powerful to begin with, and conversion lessens performance. In humid weather it helps immensely to recirculate the air so the cooling system only has to dehumidify it once.
 
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