Auto Belts

courtesy of Bob, The Auto Answer Man

Hi Bob,
I have a question on the car belt. I know there are more than one belt in car, drive belt, timing belt, etc. Excuse me if I'm wrong, but I'm not a mechanics person. My car is six year old now, is this time I should change the belt, can I do this myself? Or can I at least check to see if I need to have the belts changed?? I'm talking about both the drive belts and timing belt(s). I heard if the timing belt is broken when the car is running, it could do serious damage to the engine, but it's not cheap to change the timing belt, so I want to make sure the belt needs change before I spend the money.

Dear Mike,
Since you did not tell me what type of car you have, I can not be specific in my reply.

Let's first talk about "Fan Belts". On older cars, there usually was one fan belt per device. What I mean my that is the alternator had a belt, the power steering had a belt, the air conditioning had a belt, and so on. Sometimes one belt might drive 2 devices but generally not more than that. On newer car, they have since gone away from the "thin type fan belts" and have switched to "serpentine" belts. these belts wrap around most of the pulleys and generally drive all external devices with one or two!

How do we tell if the belts are no good? the easiest way to tell is by visual inspection. Take one belt and turn in inside out (look at the part that rides the pulleys, on old style 'v' belts, that would be the thinner side, on the newer style, it would be the side that has the groves). Look at it, if it looks dry and brittle or has cracks, replace it. On the serpentine belts, it any of the grooves are broken or worn, replace it as well. Generally this should be done about every 12-24 thousand miles (check your owners manual for exact intervals!).

To replace these belts, you can do it. You should be familiar with tools (typically a ratchet and wrenches). Do NOT, I repeat DO NOT use Vice Grips or Lock Jaw or Locking type pliers on any nut or bolt on your car!!!! This type tool is not made for auto repair! All you will do is strip the threads and never be able to remove it.

On older cars, you will have to remove all the belts to get to the ones in back. I would first recommend getting the belts first because you will not be able to drive the car while they are removed! If there is a question on a belt and you have a choice between several, get all of them and return the unused ones after the job. Most auto part store understand this and will accept the return. Just make sure you ask them first! I would suggest that you make a note or even a drawing of each belt that you remove, so you know where it goes back.

Okay, now remove all the belts (noting where the came from). Match them up with the new belts. You might notice that the new ones are a little shorter, a little is okay. The belts simply stretch over time! Now replace them in reverse order. Do not over tighten them. When the belt is installed, go to mid span and push down, you should have about one half to three quarters of an inch deflection. If you over tighten them, you will damage the bearings in the device in which they connect to!

Now watch what you use to pry against to tighten the belts! Don't just stick a tire iron in there and start pulling! They make a simple little tool that fits between the pulleys the belts wraps around. Then you turn a screw on the tool, and it pushes the pulleys apart.

Now, with all of that behind us, if you are lucky enough to have a newer car with a serpentine belt, then the job is much easier! Like before, get the new belt first. Now somewhere under the hood (usually near the front) you will see a routing map of how the belt routes. Study this! You will also see an idler arm (or pulley). This will be a device that is just a pulley with a heavy spring inside it. It is not connected to any device on the car, just bolted to a bracket. This device is sometimes called the self adjuster.

Now what you do is find a wrench or a socket that fits the nut in the center of this pulley. This is what you are going to turn to lessen the tension from the belt. It will be heavy and hard so try to find a long tool for added leverage. I would also suggest that you first read the owner's manual or your car's bible for proper instructions for your particular car. For those of you who are wondering about the "bible", I refer to the repair manual for your car as the "bible". Read it, study it, learn it, know it!

Okay, once you have removed the tension, hold the wrench or socket with one had and slip the belt off a pulley with the other. Match up the belt to make sure it's correct. Now for the hard part, reinstalling the belt. It gets a little confusing trying to remember how it came off! Refer to that map that I told you about, it will help. Now just do the reverse from before and you should have it installed.

As for timing belts, again you did not tell me what kind of car you have so this may not even apply to you. Some cars do not have "belts" they have chains. Older engines and larger engines have timing chains that drive the valve system. If your engine has a chain, then there is no need to replace it (unless it has been determined to have fault or malfunction).

As for belts, they should be changed every 60k miles. This is a hard job and if you are not very mechanical, then DO NOT DO IT. Bring it to a mechanic or at least someone that has done it before! The job should run around $300 for a timing belt replacement. If you do not do it, and the belt breaks, you run the risk of the piston coming up and hitting a valve that is open! You might get lucky and there won't be one is such a position, but that is a big chance.
Good Luck!
Drive Safely!
Bob, The Auto Answer Man

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