How to Replace A/C Hose for a Car’s A/C Blows Hot Air

This instruction will show you what causes A/C blows hot air and how to replace A/C hose. One of the symptom is air conditioning system leaks refrigerant, and that could be from hose, valves or compressor.

More cases about A/C, please click here: AUTOMATIC AIR CONDITIONER.

Below is same topic about A/C cases of different brand vehicle you may interesting:

VW Passat Air Filter & Air Conditioner Replacement

Audi Air Condition Blower Can Not Work & 01592 Trouble Repair

Benz C320 AC / Air Conditioner Trouble – Warm at Idle

How to Diagnose ISUZU Truck Air Conditioning AC Compressors System

Buick Regal Automatic Air Conditioner Control Adjustment Trouble


In this case, it was a bad low pressure hose. So here will show you how to replace A/C hose on your car and how to charge it whit the right type of refrigerant and correct weight.

For replacing AC hose we need:

Air conditioning refrigerant

A proper refrigerant gauge

A new hose

A digital scale



This is a dust on radiator hose and where air conditioning refrigerant leaks leaves this substance.


Because air conditioning container refrigerant and refrigerant oil and it will leave mark like this. This will make it easy for us to know where we have the leak.


The bigger diameter hose is the return line which is the low pressure side, and the smaller diameter is the discharge line which is the high pressure side.


With this particular car we need to remove filter bars for replacing our damaged air conditioning hose


Here we found more than one place for refrigerant leak


Before removing the hose, check if there have any refrigerant left in the system. Quick disconnect adapter lor low pressure side port. If the gauge reads zero pressure, it means all the refrigerant leaked out.


Disconnect the gauge and start form evaporator side. Unlock the 10mm nut, and pull the hose out


Removing any harness clamp and hose clamp till we use the compressor



With the new hose always make sure that it has the o-rings and lubricate them as well. It will provide better seal.

Clean everything before connecting the new hose then install new hose.

Pressurize the system till 200psi to check the connections for a leak for charging. When it reached 200psi , close the valve


Use soapy sponge for the connections to see if there any bubbles. If not, that means no leaks.


Open the valve and let the pressurized air out. Let’s vacuum the system with the air conditioning system, if there’s any moisture in the system, the air conditioning not work properly.

After do that, charge the system with the refrigerant, you can find what type and exactly how much refrigerant we put in system here



Put refrigerant on the scale and zero down


Open the gauge valve.

Start the engine and turn on the air conditioning


Waiting until it reaches the recommended weight. And while charging look at the gauge, if the gate shakes means the compressor is bad.


When it reaches the recommended weight, the return line should be cold.

Removing the gauge hose and putting the cap back, put the filter box back.

Replacement is finished.



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