Ac problem fixed and maybe more????

[duramax on fire]

So my new ride wouldn't cool at idle after sitting in the hot sun. It's been a 100 here in dallas. So I hooked my gauges up and the high side would hit 450 at idle and low was 45. So my first thought was a blockage, to much oil, or over charged. Today we drained the system and refilled with 24 oz. still hitting 450 at idle. My buddy which is a good ac guy put a fan in the front of the condenser. and pressure came down. Realized it was an air flow problem. Shut truck off and fan spun for 15 seconds. Changed the clutch and now all is good. Hopefully this will help someone down the road. My lbz never run hot even towing.


The point is maybe these fan clutches need to be replaced ever 4-5 years

Also I was getting some white hazing from exhaust at idle when it sit for a few minutes. Now nothing. Question is maybe the fan not pulling anough air affected everything else. Not sure.

 

[duramax on fire]

Shit **** me. Scratch the title. Let it sit for an hour still hitting 475 on high side.

 

[duramax on fire]

Any ideas

 

[Chevy1925]

How are you testing this? You should be running up to 2k rpm, blower on high, max a/c and when fan kicks on, you will see pressure drop. If the fan does not kick on, those pressures will happen. You can try a kodiak fan clutch or Kennedy engineering clutch which come on at 205-210* instead of 230* like stock. This helps this situation your in. I’d also make sure you t-stats are not sticking open, if they are the truck won’t get enough heat to kick the fan on even in that heat.

Go drive it on the highway or roads and get air across the front end, I’ll bet it starts blowing cold regardless if the fan is on or not.

 

[Burn Down]

How are you testing this? You should be running up to 2k rpm, blower on high, max a/c and when fan kicks on, you will see pressure drop. If the fan does not kick on, those pressures will happen. You can try a kodiak fan clutch or Kennedy engineering clutch which come on at 205-210* instead of 230* like stock. This helps this situation your in. I’d also make sure you t-stats are not sticking open, if they are the truck won’t get enough heat to kick the fan on even in that heat.

Go drive it on the highway or roads and get air across the front end, I’ll bet it starts blowing cold regardless if the fan is on or not.

^^^ Yep, A/C in these trucks doesn't work great when not moving, especially at 90+
Gotta get air moving over that condensor:thumb:

 

[duramax on fire]

Testing it when it happens. When it sits pressure goes up to 475 when high pressure cuts off compressor until it evens out after a few cycles then it evens out. To the normal pressures. It's just weird it's fine after a couple minutes. Going to pull the consider tomorrow and see how much oil is in there. I'm out of ideas.

 

[duramax on fire]

And pressure should never hit 475 on a he high side. Unless I'm clueless loll.

 

[duramax on fire]

Thanks for the replies. And I agree with them. But the difference is it will no blow cold until it warms up or cycles after that it's fine.

 

[duramax on fire]

The problem is all my other 5 trucks blow ice cold when you first start them. This one doesn't.

 

[Chevy1925]

When’s the last time you checked the orifice tube?

 

[2004LB7]

If the orifice was plugged I would think the tube post orifice would be really cold perhaps frosting up and the suction line to compressor wouldn't be very cool due to the lack of refrigerant. Thus high superheat

The suction side pressure would be low too

High discharge pressure with normal suction is normally an indicator of of a clogged up condenser or lack of air flow. It could also be from non condensables in the system such as air

 

[02greysixer]

High discharge pressure with normal suction is normally an indicator of of a clogged up condenser or lack of air flow. It could also be from non condensables in the system such as air

This. Make sure you're using good refrigerant. No parts store shit with all the stop leak and "additives" in it and not cheap Chinese stuff either. I had some trucks doing weird things and come to find out it was due to using cheap Chinese refrigerant that was full of air. Now I only use Dupont or other brands that are labeled to meet AHRI-700 and SAE J2776 purity standards.

If you're worried it's got too much oil replace the drier, o tube and flush everything out with rubbing alcohol and compressed air until it runs clean then pull a good vacuum ( I like to do an hour or so but I'm in Fl where a "dry" day for us is 85% humidity) and charge it up. I've found the GM systems get a little colder if you charge them a couple ounces light.

Sent from my SM-G930P using Tapatalk

 

[zakkb787]

Not trying to hijack but just have a quick question since it was mentioned. I’ve noticed my trucks air absolutely sucks when stopped. Would adding a small fan to the front of the condenser to kick in when you turn the ac on help this?

 

[duramax on fire]

When’s the last time you checked the orifice tube?

Pulled it yesterday and cleaned it when we discharged the system. It was pretty clean but soaked in oil and dye

 

[duramax on fire]

This. Make sure you're using good refrigerant. No parts store shit with all the stop leak and "additives" in it and not cheap Chinese stuff either. I had some trucks doing weird things and come to find out it was due to using cheap Chinese refrigerant that was full of air. Now I only use Dupont or other brands that are labeled to meet AHRI-700 and SAE J2776 purity standards.

If you're worried it's got too much oil replace the drier, o tube and flush everything out with rubbing alcohol and compressed air until it runs clean then pull a good vacuum ( I like to do an hour or so but I'm in Fl where a "dry" day for us is 85% humidity) and charge it up. I've found the GM systems get a little colder if you charge them a couple ounces light.

Sent from my SM-G930P using Tapatalk

Ok thanks. You might be on track here. When I pulled orrfice tube it was dripping with oil and dye. I may flush everything today and try that. thanks.

 

[duramax on fire]

If the orifice was plugged I would think the tube post orifice would be really cold perhaps frosting up and the suction line to compressor wouldn't be very cool due to the lack of refrigerant. Thus high superheat

The suction side pressure would be low too

High discharge pressure with normal suction is normally an indicator of of a clogged up condenser or lack of air flow. It could also be from non condensables in the system such as air

Yep. I get ice cold lines post orrfice tube all the way to the suction of the compressor. And I cleaned orrfice tube yesterday. Dripping with oil and dye. Starting to think the condenser is full of oil and trash.

And again. I did wash the condenser and radiator out when fan was pulled.

 

[duramax on fire]

Not trying to hijack but just have a quick question since it was mentioned. I’ve noticed my trucks air absolutely sucks when stopped. Would adding a small fan to the front of the condenser to kick in when you turn the ac on help this?

In my opinion you have check pressures at idle. But I'm not an ac expert reason why I'm here lol. But I have seen a compressor turn like normal and be bad.
But I would start like mine with air flow. At idle you should be able to suck a paper towel up to the grill. If it doesn't the clutch and or everything needs to be washed out.

 

[RickDLance]

Did you check the stack to make sure it was clean?

 

[Chevy1925]

Yep. I get ice cold lines post orrfice tube all the way to the suction of the compressor. And I cleaned orrfice tube yesterday. Dripping with oil and dye. Starting to think the condenser is full of oil and trash.

And again. I did wash the condenser and radiator out when fan was pulled.

Yup, i would be as well. has the system ever been reverse flushed?

 

[duramax on fire]

Stack is clean. I washed it out when I did fan clutch.

I've only had it for 4 months. Not sure if it's been flushed. It did have dye so someone has done something.

Funny thing is this morning all was good. Pressures perfect blowing ice cold. But if it sits when it's a 100 starts building to 450 until you drive it. Then will be fine all day. Wife stole the truck from me today so won't be able to pull condenser until tomorrow. Need to get a new wife lol.