compressor oil quantity

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mlelah
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Joined: Wed Jan 13, 2021 4:49 pm

compressor oil quantity

Postby mlelah » Wed Jan 13, 2021 4:56 pm

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.
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JohnHere
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Re: compressor oil quantity

Postby JohnHere » Wed Jan 13, 2021 10:55 pm

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.
Al9
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Re: compressor oil quantity

Postby Al9 » Thu Jan 14, 2021 1:47 am

I'd say to read the new compressor's label/instructions in order to know which oil is needed, since Sanden SD7H15 comps are known to use different oil viscosity grades.

SP-10 oil is PAG 46, SP-20 is PAG 100 and SP-15 is an intermediate grade oil (some say use PAG 68, which can be really hard to find in the US, but really easy to find in Europe; others say to just use PAG 100; the best option, in that case, would be to use OEM Sanden SP-15 oil, IMHO).

10ml of oil recovered from the old comp is likely the outcome of a refrigerant leak, with most of the original system oil charge that ended lodged inside the evaporator, with not enough refrigerant to carry it back to the compressor.

Keep in mind that the proper way to drain (and refill) oil with a Sanden SD7H15 is through that oil drain hole covered by a bolt on the compressor's crankcase.
mlelah
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Re: compressor oil quantity

Postby mlelah » Fri Jan 15, 2021 5:58 am

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.
mlelah
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Re: compressor oil quantity

Postby mlelah » Fri Jan 15, 2021 6:00 am

sorry SP-15
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JohnHere
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Re: compressor oil quantity

Postby JohnHere » Fri Jan 15, 2021 9:47 am

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.
Al9
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Re: compressor oil quantity

Postby Al9 » Fri Jan 15, 2021 3:01 pm

For the sake of clarity, here in Europe PAG 68 isn't OEM Sanden SP-15 - the OEM oil is pretty hard to find here too.

PAG 68 is just an easily available AC lubricant also sold as "Universal PAG" under different brands. Viscosities are an intermediate between PAG 100 and PAG 46 - for some reason the makers seem to think that older Delphis/Harrisons such as R4s and V5s are now phased out, at least in the EU.

This one is a double end capped PAG.

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