AC blows cool instead of cold

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, Dougflas, HECAT

joeld
Posts: 9
Joined: Wed Jun 06, 2018 2:20 pm
Location: Georgia

AC blows cool instead of cold

Postby joeld » Wed Jun 06, 2018 5:29 pm

Need some advise on my cooling problem please. Car is 1994 Buick Le Sabre 3800 engine. Has approx 100k and I am the original owner. The AC system is original with no repair work ever. Noticed a few days ago the vent temps were not as cold as they have always been. Outside temp was approx 80 degrees and air from vents were just cool.

Did some checking today with manifold gauges and this what I observed.

Static at 80* - low side-82psi
high side-81psi

Started engine and for the first 3-4 minutes -low side-95psi
high side-100psi

Ran car for another 10-15 minutes -low side-115
high side-125

Compressor did not cycle during this.
Any thoughts?

Thanks
Joel
Dougflas
Posts: 214
Joined: Mon Apr 18, 2016 6:10 pm

Re: AC blows cool instead of cold

Postby Dougflas » Thu Jun 07, 2018 12:45 pm

AC system not activated. Compressor not engaged
joeld
Posts: 9
Joined: Wed Jun 06, 2018 2:20 pm
Location: Georgia

Re: AC blows cool instead of cold

Postby joeld » Thu Jun 07, 2018 1:06 pm

Compressor is engaged and turning. In my first post when I said "compressor did not cycle", I meant compressor did not cut off. Stayed engaged the entire time.

Thanks
Joel
User avatar
bohica2xo
Posts: 562
Joined: Wed May 11, 2016 4:12 pm
Location: Las Vegas, NV

Re: AC blows cool instead of cold

Postby bohica2xo » Thu Jun 07, 2018 6:41 pm

If the compressor is actually turning at those pressures it is done.

Run the engine rpm up to 2,000 and watch the high side - want does it do?
joeld
Posts: 9
Joined: Wed Jun 06, 2018 2:20 pm
Location: Georgia

Re: AC blows cool instead of cold

Postby joeld » Thu Jun 07, 2018 6:51 pm

I'll check that Friday, forgot it when doing the first check!. Thanks for the reply


Joel
JohnHere
Posts: 117
Joined: Sun May 13, 2018 10:20 am
Location: South Carolina Upstate

Re: AC blows cool instead of cold

Postby JohnHere » Fri Jun 08, 2018 7:28 am

bohica2xo wrote:If the compressor is actually turning at those pressures it is done.

Run the engine rpm up to 2,000 and watch the high side - want does it do?


This.

Just curious: Does your car have R12 or R134a?
joeld
Posts: 9
Joined: Wed Jun 06, 2018 2:20 pm
Location: Georgia

Re: AC blows cool instead of cold

Postby joeld » Fri Jun 08, 2018 8:22 am

JohnHere wrote:
bohica2xo wrote:If the compressor is actually turning at those pressures it is done.

Run the engine rpm up to 2,000 and watch the high side - want does it do?


This.

Just curious: Does your car have R12 or R134a?



134a from the factory.

Joel
Dougflas
Posts: 214
Joined: Mon Apr 18, 2016 6:10 pm

Re: AC blows cool instead of cold

Postby Dougflas » Fri Jun 08, 2018 12:44 pm

I think those vehicles had control valves for the V5 compressor.
joeld
Posts: 9
Joined: Wed Jun 06, 2018 2:20 pm
Location: Georgia

Re: AC blows cool instead of cold

Postby joeld » Fri Jun 08, 2018 4:45 pm

Dougflas wrote:I think those vehicles had control valves for the V5 compressor.



Compressor is a HR6, not a V5

Joel
joeld
Posts: 9
Joined: Wed Jun 06, 2018 2:20 pm
Location: Georgia

Re: AC blows cool instead of cold

Postby joeld » Fri Jun 08, 2018 5:06 pm

OK, I did the test again today with a somewhat different finding.

Ambient temp was 88*-90* with car in shade, similar to the first test.
Static was : low side -88 high side -89

Started engine, let idle for 5 min.
Cut on AC, high speed on for cabin fan, windows down.
Low side went to 45psi-comp cut off. Low side went down to 22psi-comp cut back on.
High side went to 160psi with comp on. high side went down to 125psi with comp off.

Same readings with car at idle versus 2000rpm.

Had two box fans in front of car during this test.
Sprayed a lite mist of water onto the condensor with engine still running, low side stayed the same. High side dropped to
120psi with comp on and 80 with comp off.

Dash vents still warm.

Now the car has been running for approx 20 minutes and getting warm. I then noticed the low side pressure climbing back up towards the 100psi mark.
I sprayed the condensor again with water mist and it started to cycle on/off with the lower low side pressures (as above).

The small line going into the evaporator was cold and had a fair amount of water dripping off.

Sound like it needs some freon?

Thanks
Joel

Return to “Automotive Air Conditioning Forum”