Diagnosing a vehicle's A/C system: Low side PSI is High & the High side PSI Low

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Жыл бұрын

Learn the 4 main conditions that will cause your vehicle's A/C pressure to have low side pressure that is high and high side pressure that is low. Variable displacement compressor diagnosis is also covered.

Пікірлер: 85

@michelcarballomendez 7 ай бұрын

Gracias profesor por este video, vivo en Venezuela y tengo una mazda bt50 que cuando está estacionada, el ac no enfría, pero cuando salgo a la autopista funciona perfecto. Creo que esta mal mi fan clutch. Gracias profesor

@pixeldennis2862 4 ай бұрын

Thanks I hope you’re still around … Dealing with a 2011 Jeep compass . The low reads hifh and high a little low . I’ve seen many people having issues with these cars and people mention the tool you’re using to adjust the duty cycle … I’m hoping it’s my txv or overcharge … It was properly evacuated, held vaccum passed leak test and proper ref was replaced . The readings after this was apparently normal readings . However later on the pressures flipped again .

@pixeldennis2862 4 ай бұрын

What’s this scan tool and what are the electrical systems I need to check?

@JordanFritzsche 10 ай бұрын

Awesome video, thank you!

@PANTYEATR1 10 ай бұрын

95 Mustang, my low side is maxed out on the gauge, the high side is at zero. Compressor clutch is disengaged. What's the problem? Thanks

@RomeB-qe4mf 2 ай бұрын

Are you measuring voltage to the solenoid on the compressor=duty cycle? (ie 4V = 40% duty cycle)

@jrockaz548 2 ай бұрын

2011 highlander new compressor expansion valve condenser charged to proper level using robinair machine ac compressor and fans only stay on above 1k rpm

@caiobabe 10 ай бұрын

Excellent video. TY

@irisbaez1972 4 ай бұрын

I have a Kia soul 2012. 2.0L and the compressor are leaking a yellow liquid for some time. I've tried to seal it with RTV silicone, but I think is not working. Do you think I need to replace the compressor? This car has only 73 K miles, so why you think is leaking? We are in winter so we don't use it too much for now, but in summer this place will get 105 to 115 degrees. -- I have a quote to replace it for $ 1700.00

@timsigley5806 10 күн бұрын

Great to point information i was looking for thanks alot. I subscribed and liked channel

@christianmartinez7161 10 ай бұрын

Driver side vents blows warm at idle but cold when accelerating

@pariah7843 21 күн бұрын

I like the way he talks. It’s adoribole

@vadimlazovskiy7442 3 ай бұрын

Thanks professor., just the scenario I am having now plus one more symptom - increase rpm slightly and pressure normalizes on both sides and cold air starts blowing. Basically I have no AC at idle or stand still traffick. I would not probably notice the issue but living in NYC, traffic is where average driver spends most of the time during summer. Is this additional detail points to the compressor or blockage?

@Chris-kq7ko 20 күн бұрын

Increased rpm and your ac blows colder points to a weak compressor.

@KudirataduniSulaimon-dy1vf 10 ай бұрын

Hello please wanna learn how to repair and install car Ac

@RogerPack 3 күн бұрын

I think mine having very lsome weird readings once...fixing the idle improved things a little... at least better while idling :)

@michaelboibodas 3 ай бұрын

Hi. Just changed entire AC system(compressor, expansion valve, O-Rings, Condenser, and Schrader valves. On a Honda Accord 2.4 Liter. I vacuumed system out. Purged the yellow line of air, between Freon cans. The Low side reads 25 psi BUT THE HIGH SIDE READS 110-112!! Ambient outside temp was 65-70 dry conditions in AZ. What do the readings mean? I put a thermostat inside the car’s vents and temp read 40f! It was Ice Cold. Did I do everything correctly? Why is the high side not at 150-175psi?

@ProfessorPentane 3 ай бұрын

Hi Michael, You caught me at a good time as I do not have time to respond to all of the questions from my KZfaq videos. Your gauge readings could be normal for a milder 70F dry day with. Was the engine at full operating temp? That will cause the reading to be lower if the engine is not hot. Try switching to the fresh air mode to see if the extra heat load will raise the high side pressure a bit. But I think over 150 on a mild day is normal if you are blowing out 40F. You will not know for sure until it gets nice and hot in AZ. Thanks for watching, P.P.

@ericforest9186 13 сағат бұрын

How can we check for an electrical problem? I checked all of the fuses. Can I somehow put 12v to the compressor to force it to run?

@hasanasraf3717 9 ай бұрын

My high side reading is rattle? Is that normal?

@phillippardo5712 Жыл бұрын

What if ac blows cold on highway, couldn't still be a stuck open txv? And wouldn't a stuck open txv cause the gauges to not equalize when turned off?

@Nes_2k Жыл бұрын

Make sure fans are working properly

@rodrich870 7 ай бұрын

AC system Low side too low & High side normal . Can someone help me??

@DragonRoyZ 11 ай бұрын

I just replaced my AC Belt, previously it was always going 40psi on the low pressure port as the lowest. After I changed It, I now get 30psi easily. What is the effect of the new AC Belt?

@ProfessorPentane 11 ай бұрын

The old belt could have been slipping causing the compressor to be spinning at a slower speed. Thanks for watching.

@ShakotanRon Ай бұрын

I’ve got a v.d. compressor in my 2003 x5. I’m experiencing only 1 to 3 psi change between high and low with the clutch activated. Classic symptom of a bad compressor. Pressure was around 100psi static, and I believe it was 85+* outside. My question: is it possible for this to happen by a stuck open expansion valve, and or a low duty cycle, or stuck solenoid?

@ProfessorPentane Ай бұрын

A stuck open expansion valve would have a greater change than 1 to 3 psi, not the problem. It looks the compressor is not pumping at all with those pressure readings. Yes, it could be a solenoid problem, but hard to tell if you do not have the special tools to check. Most DYI guys will replace the entire compressor for this problem, but remember, it could an electrical problem that is causing the computer to not turn on the compressor. Also check for fault coeds. I would diagnose this problem by looking at scan tool data and use a special tool to bypass solenoid and manually control the solenoid. Again, hard to diagnose without special tools. Good luck. Does this compressor have a clutch, is it on?

@peppi7777 11 ай бұрын

I have on the low side blue gauge 30 psi and on the high side red , gauge shows maxed out psi all the way high. Any suggestions why ,and thank you

@Casualgaming763 20 күн бұрын

I think that means something is clogged

@victorcalderon007 Жыл бұрын

Can you say; get to the chopper

@DKINTHELAB Жыл бұрын

😂😂😂😂

@benwelchiv 7 ай бұрын

Hello!!! I'm watching this and I can't see my issue. Please help! Details below. What it is: 2004 Dodge Ram 1500 5.7 v8 I changed out shipping pag in ac with new pag46 3 oz in compressor (2 oz reg. 1 oz uv After replacing everything, I vacuumed system for 2 hours vacuum held Added 3 oz pag 46 (2 oz reg. 1 oz uv) system requires 6 oz. Started truck No clutch engagement Added 1-12oz can r134 to Low side (requires 22 oz.) No clutch engagement Added other 10 oz No clutch engagement Jumped 30 to 87 on relay to engage clutch New stuff: Ac compressor Condenser fan Condenser Low line High line Accumulator Pressure sensor Other: O2 sensors Pcm Throttle body Plugs Wires Coilpacks Old: Everything behind the fire wall Line from compressor to condenser What the issue is: Can't get the ac clutch to self-engage even after truck reaches OT Current ambient temp: 63 F What I have tested: 10A fuse doesn't blow anymore 72472V relay is good Power to clutch plug connector is good 14.77v Reading at ac pressure sensor is 3.7 at continuity I can jump 30 to 87 to force the clutch to engage. When clutch is engaged by jumping 30 and 87 pins in relay and engine running AC on High coldest Low side pressure: 40 High side pressure: 135 AC off with clutch engaged Low side: 33 High side: turned AC on hi/coldest when pressure reached 300 and rising, pressure immediately dropped to 140 When clutch is not engaged and engine running AC on High coldest Low side pressure: 68ish High side pressure: 68ish AC off, no change When truck is not running Same pressures as when clutch is not engaged The truck will not engage the compressor to self regulate. Please help! Am I missing something?

@AncapistanVan Ай бұрын

Thank you sir. Great video

@ProfessorPentane 14 күн бұрын

My pleasure

@ILIKE2FIXSTUFF 5 ай бұрын

I have a 2014 silverado and the ac compressor runs but doesn't seem to pump the freon around. Pressure on the low side is greater than high side which is odd. And... the cooling fans does not turn on when I turn the ac on inside the cabin. Fans work fine to cool the engine but not turning on for the ac. I unpluged the Pressure sensor and fans kick high speed. Any thoughts?

@4.8_kris 4 ай бұрын

Did you ever figure it out ?

@ILIKE2FIXSTUFF 4 ай бұрын

I replaced the expansion valve and went ahead and replaced the compressor that had a small leak. I really think the expansion valve was stuck or some. The fans will not engage with too low of pressure on high side. At least It is what I could think of. As soon as I replaced the expansion valve and compressor and refueled, it kicked in and works perfectly now.

@selvinramirez5585 3 ай бұрын

Same problem I did exactly what you did with the pressure sensor, I’m go ahead and replaced the expansion valve first before I go with the compressor since the compressor it’s on and I really hope it’s not the compressor 😥$$$ I’ll come back next 2 weeks

@vkarabin 2 ай бұрын

Can you tell me do you keep both gages in the open position or closed when testing.. thanks

@ProfessorPentane Ай бұрын

The Manifold valves should be in the closed position The service valves on the end of the hose should be closed.

@ILIKE2FIXSTUFF 5 ай бұрын

Mine is doing that. The compressor works but doesn't move the freon around on the system. Also, the radiator fan won't start when ac is turned on. Any tip on the radiator fan not turning on? I checked all fuses and relays

@ChiefColeman 3 ай бұрын

My Cruze is doing the same thing. Fuses are all good too

@ILIKE2FIXSTUFF 3 ай бұрын

Check the expansion valve if there is one there. If freon is good compressor kicks and too much pressure. Cold be the expansion valve.

@yannickn6742 Ай бұрын

Have you checked fan operation itself?

@ChiefColeman Ай бұрын

@@yannickn6742 it was a bad compressor

@bigwaves2824 3 ай бұрын

my low side is 80 psi and high side is 150 only 2 cans freon put in after changing the expansion valve high side gets real hot to touch low side is warm to touch any ideas the compressor turns and spins

@user-li2wv3vs9f Ай бұрын

I have the exact same problem 😂

@bigwaves2824 Ай бұрын

@@user-li2wv3vs9f ended up being a bad compressor the suction side was bad swapped with a junkyard compressor works great know

@user-li2wv3vs9f Ай бұрын

@@bigwaves2824 thanks for letting me know. I'll do the same.

@kilezoe6603 2 ай бұрын

I let pressure out high side because I didn't have an understanding. So I need to pull vacuum on high side ?

@ProfessorPentane 2 ай бұрын

Either side will work for pulling a vacuum before recharging the system. Thanks for watching. PP

@ronmelliad7327 3 ай бұрын

Awesome! Thanks!

@bellybell542 Жыл бұрын

very educative video

@issamadam9352 Жыл бұрын

If both are high 40-250 psi in a variable displacement compressor with IHX inspite of correct charge,what could be the cause?