Engine wear?

bigry2004 · #1 03-10-2005, 06:23 PM

newbie here. have a 97 black blazer LS with 148k miles. i noticed BlazerLT posted in a topic that running the defrost a lot will wear on your engine and wastes fuel. how much of a difference will it make by leaving it off? i guess living in michigan i didnt think much of leavin it on when im drivin around during the winter.. even if i dont need the heat, just leaving it on the windows. just a little tidbit i thought u guys could help me with. oh yea, just for an added note.. i jus had a heater core replaced and they are a bitch. im not sure how to do those, so i had it done by a trust auto shop and it was still $500. thanks

BlazerLT · #2 03-10-2005, 06:27 PM

Quote:

Originally Posted by bigry2004

newbie here. have a 97 black blazer LS with 148k miles. i noticed BlazerLT posted in a topic that running the defrost a lot will wear on your engine and wastes fuel. how much of a difference will it make by leaving it off? i guess living in michigan i didnt think much of leavin it on when im drivin around during the winter.. even if i dont need the heat, just leaving it on the windows. just a little tidbit i thought u guys could help me with. oh yea, just for an added note.. i jus had a heater core replaced and they are a bitch. im not sure how to do those, so i had it done by a trust auto shop and it was still $500. thanks

It can really hurt your economy because you are constantly running the AC compressor which puts more load on the engine.

Use only when needed and use the floor option any other time. Don't use blend.

metallica21156 · #3 03-11-2005, 08:25 AM

as soon as you go below 40 F the AC compressor will not turn on. i read it some where and mine won't turn on if its that cold. so really your fine if its below that. any higher then 40 and it will run.

BlazerLT · #4 03-11-2005, 03:02 PM

Quote:

Originally Posted by metallica21156

as soon as you go below 40 F the AC compressor will not turn on. i read it some where and mine won't turn on if its that cold. so really your fine if its below that. any higher then 40 and it will run.

Defrost will turn the AC compressor on to dehumidify the air. Doesn't matter what temperature.

metallica21156 · #5 03-12-2005, 02:16 PM

blazerLT. i'm telling you its true. next time its below 40 or snowing. turn your defrost on and open the hood. you will see the AC doesn't run. also you will notice that the RPMs don't bounce up and down when the compressor kicks in. the only time it might drop is when you turn the switch. if you don't bealeave me go out and look. if yours does work then maybe its time to have mine looked at.

tom3 · #6 03-12-2005, 03:38 PM

These run off a pressure switch. At low temps the pressures are pretty low and the compressor will cycle some, runs very little. Could be a temp switch on the new stuff, everything is more complicated on them, more to go wrong. General theory is that the compressor needs to run now and then to keep the seals lubed anyway.

BlazerLT · #7 03-13-2005, 12:13 AM

Quote:

Originally Posted by metallica21156

blazerLT. i'm telling you its true. next time its below 40 or snowing. turn your defrost on and open the hood. you will see the AC doesn't run. also you will notice that the RPMs don't bounce up and down when the compressor kicks in. the only time it might drop is when you turn the switch. if you don't bealeave me go out and look. if yours does work then maybe its time to have mine looked at.

Just did it, and yip, mine runs.

metallica21156 · #8 03-13-2005, 08:42 AM

and it was below 40? i might have low pressure then.

JParrott · #9 03-13-2005, 09:05 AM

It has to be something along those lines of low pressure because I run mine on blend almost every day when I start my Blazer up in the morning and let it run for 4-6 minutes, and my compressor cycles almost instantly. Temps here are in the teens every morning. I had my system recharged this last summer. However, I disagree with the engine wear theory. A part of the compressor cycling is to dehumidify the air, but I've also been taught that it's to keep the lines and seals lubed and in good condition when temps are too cool for people to run the A/C a normal amount of time. I don't believe that running it promotes engine wear any more than normal. It will definently increase gas usage and promote poor mileage but not engine wear.

BlazerLT · #10 03-13-2005, 02:25 PM

Quote:

Originally Posted by metallica21156

and it was below 40? i might have low pressure then.

Listen, just stop questioning this would ya, I am getting a little tired of it.

The AC uses the friggin AC compressor to dehumidify the air when using defrost and that is FINAL.

molehole · #11 03-13-2005, 02:30 PM

Why use a/c when you don't need it? Wastes a lot of extra money on gas and you don't need it in the winter except to defog the windows. Using the compressor too much will definately wear it out quicker. just my 2 cents

BlazerLT · #12 03-13-2005, 02:48 PM

Quote:

Originally Posted by molehole

Why use a/c when you don't need it? Wastes a lot of extra money on gas and you don't need it in the winter except to defog the windows. Using the compressor too much will definately wear it out quicker. just my 2 cents

Very true. Use defrost or blend until the windows are clear and then switch it to vent or floor to save money.

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