Automotive

A/C maintenance - what does this exactly mean?

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  • Nov 2nd, 2010 1:21 pm
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[OP]
Jr. Member
Sep 14, 2010
120 posts
Halton Area

A/C maintenance - what does this exactly mean?

Am a bit confused by this statement:

"Caring for the A/C system
Run the air conditioning at least once a week during the cold weather months. Run it for at least ten minutes while driving at a steady speed with the engine at normal operating temperature. This circulates the lubricating oil contained in the refrigerant. In cold weather, never turn the fan off except during the first few minutes of operation. Your climate control system will work best if you keep air circulating."

My understanding of the word "A/C" is that it "conditions the air" - hence even if heat is coming out during winter months, the A/C, so long as the button is "on", is working.

However, the quote above indicates the need to circulate the "lubricating oil contained in the refrigerant" -- in order to circulate this lubricating oil, does this mean I have to have cold air coming out of the blower even during winter months? (eg. in short, for me to circulate this lubricating oil, I have to make the interior of my vehicle really cold even if it's freezing outside as it talked about refrigerant and not heater? does this make sense?)

Thanks for your help.
5 replies
Deal Addict
Oct 19, 2006
1877 posts
122 upvotes
Typically on new cars if you run defrost the AC is on, even in the winter :)
Deal Fanatic
User avatar
Dec 28, 2007
6767 posts
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Alberta
discovermac wrote: Am a bit confused by this statement:

"Caring for the A/C system
Run the air conditioning at least once a week during the cold weather months. Run it for at least ten minutes while driving at a steady speed with the engine at normal operating temperature. This circulates the lubricating oil contained in the refrigerant. In cold weather, never turn the fan off except during the first few minutes of operation. Your climate control system will work best if you keep air circulating."

My understanding of the word "A/C" is that it "conditions the air" - hence even if heat is coming out during winter months, the A/C, so long as the button is "on", is working.

However, the quote above indicates the need to circulate the "lubricating oil contained in the refrigerant" -- in order to circulate this lubricating oil, does this mean I have to have cold air coming out of the blower even during winter months? (eg. in short, for me to circulate this lubricating oil, I have to make the interior of my vehicle really cold even if it's freezing outside as it talked about refrigerant and not heater? does this make sense?)

Thanks for your help.
Turning the system on at least once a week circulates the lubricating oil around to keep the parts and seals lubricated. Keeps the seals from drying out and prevents leaks.
Deal Expert
User avatar
May 10, 2005
34319 posts
8144 upvotes
Ottawa
discovermac wrote: Am a bit confused by this statement:

"Caring for the A/C system
Run the air conditioning at least once a week during the cold weather months. Run it for at least ten minutes while driving at a steady speed with the engine at normal operating temperature. This circulates the lubricating oil contained in the refrigerant. In cold weather, never turn the fan off except during the first few minutes of operation. Your climate control system will work best if you keep air circulating."

My understanding of the word "A/C" is that it "conditions the air" - hence even if heat is coming out during winter months, the A/C, so long as the button is "on", is working.
However, the quote above indicates the need to circulate the "lubricating oil contained in the refrigerant" -- in order to circulate this lubricating oil, does this mean I have to have cold air coming out of the blower even during winter months? (eg. in short, for me to circulate this lubricating oil, I have to make the interior of my vehicle really cold even if it's freezing outside as it talked about refrigerant and not heater? does this make sense?)

Thanks for your help.
The refrigerant does contain a lubricant and it does circulate. On some cars, when you have defrost on, the A/C automatically comes on, on others it does not. So, to be certain, the OEM asks you to turn the A/C on ocasssionally to circulate the fluid inside the A/C syatem.
You are correct, the A/C conditions the air, it generally dries it out. No, you do not have to have colsd air coming out in the winter time. Just turn it on. It is a good idea to turn it on in the winter anyway, as I mentioned before, it dries the air out and may help to prevent your windows form fogging up.
[OP]
Jr. Member
Sep 14, 2010
120 posts
Halton Area
Pete_Coach wrote: The refrigerant does contain a lubricant and it does circulate. On some cars, when you have defrost on, the A/C automatically comes on, on others it does not. So, to be certain, the OEM asks you to turn the A/C on ocasssionally to circulate the fluid inside the A/C syatem.
You are correct, the A/C conditions the air, it generally dries it out. No, you do not have to have colsd air coming out in the winter time. Just turn it on. It is a good idea to turn it on in the winter anyway, as I mentioned before, it dries the air out and may help to prevent your windows form fogging up.

Ok thanks Pete and the rest of the people who answered. I wont freeze inside the vehicle then (thankfully). The word "refrigerant" threw me off there - I had mistakenly thought that cold air needed to be coming out for at least 10 minutes (per OEM) even during our sub 0 winter temps. I'll just turn on A/C then while heat is blowing out of the vents and I should be fine, perfect!
Deal Expert
Mar 23, 2004
25631 posts
5921 upvotes
discovermac wrote: My understanding of the word "A/C" is that it "conditions the air" - hence even if heat is coming out during winter months, the A/C, so long as the button is "on", is working.
Yes A/C compressor operation in cars, is independent of whether you have selected hot air (passing through the heater core) or cool air (bypassing the core). However in most cars the compressor will not run below a certain temperature, usually something in the range of +5 to -5 C, depending on how the manufacturer designed it.

In cars with A/C, typically all HVAC air passes through the evap core but the heater core path is selectable. The evap core is "ahead" of the heater core, so heated air may also be dehumidified* if desired (which is usually the case with defroster operation in colder temperatures) which is how the A/C can still be effective when using the a hot air selection in the cabin.

*Dehumidification is a side-effect of cooling the air with the evaporator in an A/C system.

In some cases, if you manually request the compressor (i.e. using the A/C button) below the cutoff temperature, it will still engage for a short time but then disengage due to the temperature restriction shortly thereafter.

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