I have an 04 Mazda 3 hatch (2.3 obviously). It has highish miles (145k) and bought it with 137k. It has been making a ticking (sounds like metal on metal) noise for the last month. I did a full synthetic oil change right before winter. In March it started making a weird noise under acceleration from 2.25 RPM and up. I checked the oil and it was super low - drained out about 2 quarts. I used an Amsoil engine cleaner product and replaced the oil with 3.5 quarts Castrol 5W20 and 1 quart Lucas. Needless to say the noise is still there.. Upon further inspection it seems like the oil canister housing was cracked and slowly leaked out oil over the winter. I replaced the canister housing with the spin on type from the 2.0 and the oil level is still the same as when I changed it in March. I don't know for sure if the oil loss is what caused this noise to start or not. I've been told by a friend and the Mazda dealer that it is likely a stuck valve lifter; however, the noise does not occur while the engine is cold unless I force it (rev it up in neutral to like 3k RPM). It does not happen at all until 2.25 RPM. Another friend ran a compression check and I am at 190 psi at each cylinder. The spark plugs also look good and are gapped correctly (looked like they were likely changed at 100k or later). There is no noticeable loss in performance or mileage (I am actually getting better MPG as I try to shift before 2.25 RPM to avoid the noise). The car idles perfectly normal and starts up without hesitation. The transmission shifts smooth like butter. Is there anyone in the St. Cloud area or somewhere reasonably close that could have a listen or is familiar with this engine? I don't really want to stick $1000+ into a valve job that likely won't fix the problem.. Thank you in advance.