I've got a 2000 isuzu rodeo with @ 115k miles on it. The manufacturer recommends replacing the timing belt at 100k, so I'm getting it done. The places I've called for an estimate suggest replacing the water pump at the same time, which adds about $200 to the bill. Is it worth getting it done? Is it necessary? I understand that the timing belt and water pump require the same degree of engine dissassembly to replace, which is why it's suggested to do both at once. I'm wondering what the chances of water pump failure actually are and if it's worth shelling out the added $$$ at this time. Thanks in advance for any help.

I have a Rodeo with about the same mileage and I'm getting ready to do mine. I'm gonna go ahead and do the water pump too. I had a toyota with about 108k and my water pump bearings went bad and started making a lot of noise about a week before my timing belt broke, so I did those both at once. Also, the starter on my '98 Rodeo started giving me problems at about 110k. The solenoid would just click once and that's it. I'd have to keep trying to start it and it would finally start after about 5-10 tries. Anyway, the contacts in the starter solenoid were worn out. This is an easy fix. I ordered a new set of contacts and plunger for about $20 and replaced those myself and it's good as new. If you haven't had starter problems yet, I'd recommend going ahead and ordering the contacts and plunger so you'll have'em on hand. Apparently, this is really common. Those Nippondenso starters are really good and you shouldn't have any problems other than the contacts wearing out. Whatever you do, DON'T replace it with a $150 reman one from the parts store, fix it yourself for about $20 and an hour and a half of your time. If you want, IM me and I'll tell you where to order the starter contacts from. If not, just keep it in mind for the future. By the way, I'm NO expert, this is just my experience. Hope it helps.

I dunno. I mean I have the feeling if it ain't broke don't fix it. But if they are cutting you a deal since they are already gonna be down there tearing it down I might would consider it. I do all my own work so I don't know if that price is accurate or not.

Definitley get the timing belt replaced!  I will never forget that retchet Buick Skylark with a Quad 4 in auto shop and it was almost 10 years ago!. Jackass never changed the belt and it broke. 9 or 10 of the 16 valves were bent to shit. They insisted on just replacing the head instead of getting a new one. They finally came around after I worked for 2 days trying remove one of the valves and never got it out. I would loved to have seen that head check for cracks. I bet it had cracks the size of a fault line inside it.

Standard procedure in my shop. If you do a timing belt that also runs the water pump we always suggest replacement. Reason for this is the cost isn't THAT much more and it just makes sense.

I'd do it.

My 01 civic's at 97K.  At 110K (suggested change) I'm going to have all the belts done at the same time.  I figure they'll have to take or remove most of them to ge to the timing belt, and they'll already have the hood open.  Also gives you a piece of mind for when taking it on longer trips, knowing it has all NEW belts under there.  I order factory/oem replacement belts online for cheap, then will just take it to the shop and let them do it.   I'd really hate to drive my car around with one new belt, and have another one there with 110K, only to have it break at any moment.  The cost of replacing it and a tow to the shop makes getting them all done at the same time worth it.

Thanks for the responses guys. I had pretty much made up my mind to get both done before I posted, but wanted to hear some other thoughts.

You may also consider replacement of the idler pulley, it may be a spring loaded pulley or fixed. Either way the bearing could go bad and since you have it apart already its cheap insurance. Replacing the water pump is a good idea, however $200. more seems alot to me.