Depends on the model, year, engine size, and accessories that are in the way. Most shops go by a "flat rate" guide that spells out every part of a procedure for a given model, then adds or subtracts small amounts for things that add difficulty or when two things can be combined into one procedure. That way all shops quote the same times and the only variables are their hourly shop labor rate, and whether they're including extra things to insure the reliability of the repair, (which means they have your best interest at heart), or if they're cutting corners in an attempt to save you money or so they can provide a lower estimate to get the job.
You listed the wrong engine size so I can't look up the parts. If the water pump on your engine is driven by the timing belt, it is foolish to not replace it too since its failure can lead to failure of the new timing belt. If you have an "interference" engine, a broken timing belt results in bent valves and that turns into a real expensive repair. All conscientious mechanics will insist on replacing the water pump at the same time the belt is replaced. There may also be a hydraulically-controlled tensioning device for the belt and that should be replaced to insure the quality of the repair.
If you don't trust the estimate you were given, get a second opinion from a different shop, but then be sure you're being quoted for the same parts and procedures. You didn't say why the belt is being replaced, and you didn't provide any other details, so my only recommendation, if it applies, is for that second opinion, don't ask for the cost to do a repair that was recommended by the first shop. Let the second mechanic perform his own tests and diagnosis, then see what he comes up with. If you just ask for an estimate to replace the belt, they may not bother to inspect the other parts like the water pump or tensioning pulleys, then they'll have to surprise you later with those extra things they didn't know about.
Some insecure mechanics who don't have confidence in their skills may purposely berate the first estimate in a misguided attempt to make them self look better by cutting their competitor down when they know about that first estimate. Other mechanics, if they're friends with the people at the first shop, may purposely give you a much higher second estimate to make their buddies look good. Experienced mechanics will never take on a job based solely on someone elses word or based on the request of an uninformed or uneducated customer. By "uneducated", I mean a typical person who isn't expected to know all the things that can go wrong by cutting corners, all the legal ramifications of working on a car, and all the extra things we do to look out for your best interest in the long run. Most of us try to save you money, but not when it means the repair will last half as long or the procedure is not a good value.
Friday, September 19th, 2014 AT 10:45 PM
I forgot to add that for my '88 Grand Caravan, the timing belt takes about four hours to replace, and another half hour for the water pump. An experienced mechanic will get it done in a lot less time but you would still be charged 4 1/2 hours. An inexperienced mechanic who doesn't know exactly which tools to grab, which bolts have to come out, etc, will take longer than 4 1/2 hours, but that's still what you would be charged. That's what is meant by flat rate. You get charged for the amount of time specified regardless of how long the job actually takes.
My van is pretty easy to work on and take apart. There are a few engines that are so complicated that removing the engine is necessary to replace the timing belt. Fortunately there aren't many cars like that. Most engines newer than mine are packed in so tightly that a lot of extra stuff has to be removed, and that takes time that is already factored in to the flat rate times. As a general guess, I'd suggest yours may take six hours, but that's a major generalization. If you were quoted twice that much time, don't run and complain that I said it should be less. If you were quoted less time, that doesn't mean they're doing shoddy work. I'm only suggesting that there's very few engines where the timing belt can replaced in only two or three hours. There are some engines that use up to four camshafts instead of one, and they require very uncommon specialty tools to do the job, and those could take perhaps eight to ten hours or more. I suspect yours will fall somewhere in the middle of that range.