How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask david craig Your Own Question
david craig
david craig, Auto Mechanic
Category: Lincoln
Satisfied Customers: 901
Experience:  owner/mechanic at 3D Automotive
4993992
Type Your Lincoln Question Here...
david craig is online now
A new question is answered every 9 seconds

Start engine, turn ac on, ambient air blows out, open hood,

Customer Question

start engine, turn ac on, ambient air blows out, open hood, ac clutch not engaged. Drive to work 5 miles later cold air comes out of vents. go to lunch no cold air, drive 2 miles cold air. end of day, drive home drive 20 miles before cold air comes out.
next day start car in driveway (no cold air) let run for 10 minutes, get in car with cold air coming out. ???
Won't check answer until later in day.
Submitted: 4 months ago.
Category: Lincoln
Expert:  david craig replied 4 months ago.

Hi Im david, it wouls seem to me that maybe the lowpressure switch is intermittently operating. it could be a numbe of things, but i would concentrate on that first

Customer: replied 4 months ago.
where is the low pressure switch located? If I put a meter on it what should i get? Is it $40 a question or hopefully a dialog.
Expert:  david craig replied 4 months ago.

no its not 40.00 a question...lol, give me a few and i will let you know where it is

Expert:  david craig replied 4 months ago.

you can put a jumper wire in the connector to see if the vehicles ac stays on/cold. or the proper way to do it is to hook up ac manifold gauges and with the ac on, see what psi the ac cycles at on the low side... should be around 30-40....high pressure side should cycle around 280-300

Expert:  david craig replied 4 months ago.

Have you tried anything that I suggested?

Customer: replied 4 months ago.
Sorry David, I've been sick, maybe I'll try tomorrow.
Expert:  david craig replied 4 months ago.

feel better......keep me posted

Customer: replied 4 months ago.
Finally back with the living. Jumpered the low pressure switch and ac clutch didn't engage. Hooked up set of gauges and WOW! Low side pegged needle full max - high side 200. .
Expert:  david craig replied 4 months ago.

you didnt still have the jumper in the low pressure connector did you?

Customer: replied 4 months ago.
No, reinstalled on dryer
Expert:  david craig replied 4 months ago.

ok.well we gots a problem....gimme a few

Expert:  david craig replied 4 months ago.

what do the gauges read with the car shut off and the valves closed?

Customer: replied 4 months ago.
I just drove downtown (25miles) and back
earlier readings were compressor running but not cooling. When i got back the cold air temp at the middle vent was 59 degrees. Outside air 100 degrees Attached is a jpg of the gauges hooked up engine running compressor working 59 degrees
Ilk go out now and check guages not hooked up.
Expert:  david craig replied 4 months ago.

that low side is crazy. now if it were to stop at 120 being the outside temp is 100 then id say thats ok. there is actually supposed to be some kind of retard built into that gauge to keep it from passing 120

Customer: replied 4 months ago.
Heres pic of guages.
Expert:  david craig replied 4 months ago.

open up the valves on the pressure ports

Customer: replied 4 months ago.
open up the valves on the pressure portsNot sure what you mean.my last reply was to your question "what do the gauges read with the car shut off and the valves closed?"
Expert:  david craig replied 4 months ago.

sorry ...car shutoff with the valves at the ports open.

Customer: replied 4 months ago.
Guages hooked up, valves ooened, engine not running
Customer: replied 4 months ago.
Just noticed you have zero ratings - are you new at this?
Expert:  david craig replied 4 months ago.

I have 38 ratings. ive been a mechanic for 32 years. but ive only been on here for 2 weeks

Expert:  david craig replied 4 months ago.

if thats with the car not running and the valves at the service ports open. then you have a low charge and need refrigerant.

Expert:  david craig replied 4 months ago.

those gauges should be reading very close to the outside air temp. both of them

Customer: replied 4 months ago.
Ok, so when i hook up new can of 134, how do i know when i have enough?
Expert:  david craig replied 4 months ago.

i will send you the process. give me a sec

Expert:  david craig replied 4 months ago.

depending on the outside air temp you want to charge the system to when the low side shuts off at half the outside air temp. for example if the temp is 80 then the low side would cylcle off around 40. and the high side would kick off about double the outside temp around 160... then you know you have a good charge. before you do all that see what they arte cycling at now. dont forget to have the car running and ac on max for all of the above steps

Customer: replied 4 months ago.
Sorry David. I've restored numerous classic 57 Chevy's, raced a big block Camaro, now I'm into WW2 and Vietnam military vehicles., I'm very comfortable working on any part of an automobile or truck. However, this is my first time digging into an Air Conditioner system. Meaning, everything I've sent you was most likely wrong. The reason the gauge readings were FUBAR was because I didn't know how to properly use the gauges. The pegged readings on the low side was because I was opening both valves on the gauge manifold.
I figured this out because I was thinking this new set of gauges was bad so I installed them on my truck with a perfectly functioning AC system. The light bulb went off when I opened the manifold high side and the low side gauge went to the gauge max peg DUH...
Earlier I had hooked up one of those pro-system AC recharge bottles.and the gauge said I had enough refrigerant installed, (see pic)
So I kicked myself in the butt and reinstalled the gauges. Notice picture with both needles reading about same. Engine off, port valves open, manifold valves closed. Other picture shows engine running, valves set same as above. High side needle was fluctuating between 225-275.
When I shut down engine both gauges returned slowly to previous picture.
Sorry for the bad communication, hope this will help you.
Larry
Expert:  david craig replied 4 months ago.

everything looks good...is it cooling good?

Customer: replied 4 months ago.
its cooling good but still takes 5 -15 minutes for the compessor to kick in.
Expert:  david craig replied 4 months ago.

wow. that aint right...let me look into that

Expert:  david craig replied 4 months ago.

ok. the next time you start the car. turn the ac on. if it doesnt start cooling right away, open the hood and see if the compressor clutch is turning. if not then smack it with a wrench or something and see it if starts to turn. it may be a sticking clutch or the air gap might be just a tad far.

Related Lincoln Questions