I currently own a 2005 Mazda 3i that I purchased brand new back in November of 2004.

Since the car has been out of warranty for some time now, I try to take care of most of the simple mechanical fixes and maintenance such as oil changes, brakes, belts, plugs, coolant changes, and any other simple to moderate mechanical fixes.

Luckily, I've had a really good run with this car. No major repairs as of yet.

HOWEVER, I've noticed that for some time now that I've had a really rough idle as well as a lot of engine compartment noise. So I turned to google to see and compare with other owners having the same issue.

There were a few issues that seemed to consistently pop up. One being the tensioner pulley and the other being the passenger side motor mount. There were some people who started having issues with the timing chain tensioners but that was a select few and even I know that a loose timing chain makes a ton of noise. Noise that I was not experiencing. The noise wasn't coming from under the valve cover so I wasn't concerned about the timing chain or a spun rod.

So first things first, I went to Napa and purchased a $22 tensioner pulley.

The tensioner pulley is located right at the top of the engine. It took me all of 10 minutes to replace. Here is a good write up for this fix.

This did take some of the noise away and the idle did smooth out a bit but there was still something else making noise. The pulley was definitely bad as the bearings were completely worn out. The pulley spun like a skateboard wheel which is a sign that the pulley is completely worn. Many people don't always realize that a tensioner pulley shouldn't spin that freely.

So next I ordered the passenger side motor mount. from Rockauto.com. It's a pretty easy fix according to this excellent write up by a forum member over at the Mazda3 forums. Here is a link to that write up.

However, I did run into one major issue. There are two bolts and two nuts that need to be loosened. The nuts on the top part of the mount that connect to the engine are really really fucking tight. It's why you need a breaker bar to get them loose. I had both bolts loosened and one of the nuts and when I went to loosen the top nut, it stripped. It stripped so bad that it actually stripped the square connector part of the ratchet extender as well as the nut. This was also after I used a fair amount of WD40.

So it was off to Sears to buy a nut/bolt extractor.

Once I got it off (picture of removed bolt) it was smooth sailing. However I did need to hunt down a new flange nut as I knew that the old one would be unusable after I was able to eventually remove it.

Once that last nut was off, it took all of about 15 minutes to install the new mount. Very simple fix if everything goes according to plan. I can also tell you that this mount was definitely the main culprit of my engine compartment noise. Everything feels a lot smoother and sounds a hell of a lot better. Almost feels like a new car.

Here is a picture of the old shitty (Ford) mount that I pulled out of there. As you can see, the rubber boot is completely torn. When that tears, all of the fluid leaks out of the mount in turn rendering it completely useless. The failure rate on these mounts is extremely high. It's amazing that a recall has never been issued for this part.

I hope this helps some of you guys!