Replacing the water pump while changing a timing belt -- good idea or waste of money?

Dear Car Talk

Dear Car Talk | Feb 01, 1996

Dear Tom and Ray:

I have a 1990 Honda Prelude. The owner's manual recommends changing the timing belt at 90,000 miles. I took it to a repairman for an estimate, and he also recommended that I change the water pump. He said water pumps only last about 80,000 miles, and if it were to go out, antifreeze would leak on the timing belt, and the belt would have to be replaced again. What's your opinion on the water pump?

RAY: I agree, Karol. I'd change the water pump, too.

TOM: First of all, you know that the timing belt is serious business in this car. On some engines (including most Hondas) if the timing belt breaks, the valves can get crushed by the pistons. And that can easily ruin the engine. So you're absolutely right to treat it as preventive maintenance, and change it when the owner's manual recommends.

RAY: And I'd look at the water pump the same way...not because it's going to leak antifreeze, but because the water pump in this engine is driven by that timing belt. And if the water pump seizes (which they tend to do after 80,000 to 100,000 miles), even that new belt will go kablooey, and again, it's bye-bye engine.

TOM: The other reason to do the water pump now is that there's a lot of common labor in these two jobs. So if you're doing the timing belt anyway, all you really end up paying for the water pump is a little bit more than the cost of the part.

RAY: It's like my brother's brain surgery, Karol. While they were in there, the doctor said they might as well take care of the hemmorhoids at the same time.


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