Automotive Air Conditioning Information Forum

Hi, I have a 2005 Jeep Liberty 3.7L. I am rebuilding the AC system. The system worked but not well and a technician said that the compressor is likely going. I am replacing the compressor, condenser, pilot tube and drier. I drained the old Sanden compressor and got about 10 ml of oil. I drained the new compressor and also got about 10 ml of oil. I now need to add oil to the compressor. Does 10 ml sound right? If not, how much should I add? Also, after I add the oil I need to rotate the compressor 10 times. Which direction? Thank you.

The oil specification for your vehicle's A/C system calls for a total of 8 ounces (237 ml) of PAG-46. Starting with a completely empty system is the only way to know that you have installed the correct amount. Otherwise, you'll be guessing about how much to put back in, risking that it won't be enough and potentially starving the new compressor of lubrication.

mlelah wrote:I am replacing the compressor, condenser, pilot tube and drier.

Since you're not replacing the evaporator and lines/hoses, I would thoroughly flush those components to ensure none of the old oil remains in the system. If the old orifice tube (you called it a pilot tube) has any black gunk or other debris on the screen, I would flush the aforementioned parts anyway to ensure no contaminants remain in the system. If they do, your new compressor will have a very short service life, and it won't be covered under the manufacturer's warranty.

mlelah wrote:I drained the old Sanden compressor and got about 10 ml of oil. I drained the new compressor and also got about 10 ml of oil. I now need to add oil to the compressor. Does 10 ml sound right? If not, how much should I add?

10 ml is only 0.3 ounce, which is next to nothing.

Here's what I would do: Flush the evaporator, hoses, and lines as said previously. Then distribute the 8 ounces of PAG-46 throughout the system, with 1.5 ounces each in the evaporator and condenser; 2 ounces in the accumulator; and 3 ounces in the compressor. This way, you'll know for certain that the system has the correct amount of oil in it.

mlelah wrote:Also, after I add the oil I need to rotate the compressor 10 times. Which direction?

Rotate the compressor by hand in the same direction that it turns when installed in the vehicle.

Thank you all. I was actually going to ask about the grade of PAG oil. Yes the compressor calls for ST-15. And some say use PAG 46 while others say PAG 100. I have both. Can I mix? This will then be real close to ST-15.

sorry SP-15

I contacted Sanden about the oil spec. In the USA, if you are in fact using an SD7H15 fixed-displacement compressor, the Type C models use OEM SP10 (PAG-46) oil while the Type B models use OEM SP20 (PAG-100) oil. OEM SP15 (PAG-68) is common in Europe but is not typically used in the USA, as mentioned previously.

It appears that your new Sanden compressor is a European-spec part, though, since it specifies OEM SP15. If you're in the USA, contact this forum's sponsor to determine whether that oil is available here.

I've never done it, but I wouldn't try mixing oils to approximate the PAG-68 viscosity. It'll be guesswork at best and might void your warranty.