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Q: Water pump is leaking, do I need to replace the timing belt, too? The car also has a misfire on cylinder 3.

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I brought my car in to the shop for a valve cover gasket replacement (my dad was gonna replace my wires and found a bigger problem), and today they called saying it's leaking a little oil, but my car is "known for that"... And my water pump is leaking and when they replace that instead, they need to do the timing belt, too. This is going to cost $900. I'm really wondering if I should bother. The issue I was having was the engine misfiring every time I stepped on the gas and the code I got was misfire in cylinder number 3.

My car has 235000 miles.
My car has an automatic transmission.

A: Hi there. If the engine has too many miles...

Hi there. If the engine has too many miles on a timing belt, then a timing belt is suggested for replacement. The misfire for cylinder 3 could be caused by a spark plug failure, fuel injector failure, or a problem with the cylinder.

First, check for the fuel injector. Start the engine and disconnect the harness to the fuel injector for cylinder 3. If the engine sounds different, then the fuel injector was working. If the engine has no difference in sound, then the injector was not working and needs to be checked.

Next, check the spark plug for a solid blue / orange spark. If the spark is weak, the plugs and wires need to be replaced as a set.

To check the cylinder if it is getting hot enough to burn fuel, put a compression tester on cylinder 3 and crank the engine over. There should be more than 130 psi.

If you need further assistance confirming the misfire diagnosis, then a certified technician from YourMechanic, can come to your car’s location for a second opinion on the car.

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