CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Okay to drive without AC belt?

I have a 2006 Mazda3 hatchback, with the 2.3L engine.

Last night driving home the AC belt broke. There was a lot of smoke from the belt melting a little in one spot. I don’t know if the compressor seized (or something like that), causing the belt to start to melt, and then break. Or if the belt broke, jammed in something, and then melted a little, causing the smoke. The melting is just a little bit on one edge of the belt, it doesn’t look like much, for all the smoke and smell it produced. The break in the belt is right in the middle of the couple inch section where the melting/glazing can be seen.

The car seems to be running fine, no check engine light, no codes when I checked the computer. Is it okay to keep driving the car for a couple days, without an AC belt? Or should I take it straight into the shop?

Also, this is the belt that goes from the crankshaft pulley down to just one other pulley below it. (There is a separate belt that goes to the alternator and water pump, higher up on the engine). Am I correct in concluding that this is the belt to the AC compressor?

One other odd thing, if anyone has any thoughts about it. Immediately after the belt broke, I noticed that I could hear a static interference sound through the stereo when the CD player is on, but no music is playing. I use the CD player all the time and am sure that the sound started immediately after the belt broke. Does that make any sense somehow?

Thanks for any thoughts on this.

If this belt is for the AC only then you should have no trouble driving it for a few days. The AC also helps dehumidify the air in the vehicle when you use the defroster setting so it needs to function. A lot of vehicles here in the Southeast have the AC belts removed because of an “old wives tale” that says it increases fuel economy. It’s nonsense of course but the vehicles don’t seem to be any worse for wear.

I have no idea about the static unless the belt drives the alternator.

Well, you said that the belt that broke also drives another pulley. Unless that pulley is an idler for that belt, then you better not drive it.

Thanks for the responses.

@EllyEllis I said the belt in question goes from the crankshaft pulley to what I believe is the AC compressor pulley. The “one other pulley” that I described is the only other pulley on this belt (other than the crankshaft pulley itself) and I was simply asking if I’m correct in concluding that this is the pulley for the AC compressor (for anyone familiar with the Mazda3).

@missileman, yes the static is weird. I’m sure this belt does not drive the alternator, because I can see clearly the other belt that’s driving the alternator and water pump. I also checked the voltage coming off the alternator in the computer stats (I have a bluetooth dongle and phone app that can read the computer) and it seemed normal (about 13.97 V). I was wondering if somehow without the AC compressor turning that just creates some feedback in anything grounded to the engine. Or maybe with the AC belt broken off it slightly effects the load on the second belt, now that the crankshaft pulley is only driving one belt, and that somehow slightly effects the load on the alternator in a way that creates a strange frequency? It’s very weird. But as I said, I use the CD player so much that I know that sound wasn’t there before. I’m just concerned that it could be a sign of some other problem in the electrical system.

Driving without the belt won’t hurt anything. As missileman said already, the AC helps dehumidify the car. If you can live with it this way, leave the belt off as long as you like. I had a Plymouth sundance with the same issue. I drove it without the belt for 11 years.

Thanks markmast. Yes, I’m aware of the defrosting function of the AC (actually I find it annoying that the AC turns on automatically in my car in defrost, defrost+feet, and feet positions–I don’t always need it and would like more control).

Anyway, I definitely plan to fix this. I gets very hot where I live. I just wanted to make sure it’s okay to drive the car around for a few days, until I get a chance to take it in.

It’s possible that when the fried belt broke it whapped the alternator and got some pieces in it. Try blowing it out and see what happens.

As to driving without it, you can do that forever. The idea of all cars having air conditioning is a fairly recenet one. Even in '72, when I bought my first new car, AC was an option not common to orddinary (non-luxury) cars. My '89 Toyota pickup didn’t even have AC.

Thanks for the idea about the alternator. I’ll check that out.