Mazda Repair: intermitent engine ticking sound, synthetic engine oil, hydraulic lifters

Question
my 1989 mazda 323 OHC engine has an intermitent ticking sound coming from the top end, it will tick for about ten seconds then stop, then start again,and repeats  it does this at any speed, idle or driving and when engine is fully warm. any ideas??

Answer
The most common cause is air bubbles in the hydraulic lifters.  The main remedy is the use of a full synthetic engine oil (we use Valvoline 5w-30) and a Mazda filter.  Use of a K&N , some Fram and a Micro brand filters also work.  These filters have check valves that limit back flow through the filter, not all filters do. Without the check valve equipped filters each time the car is shut off the oil drains back into the pan via the oil galleys.  When you start it back up the air in the lines is pushed into the lifters which create a collapse in fluid pressure within the lifter that results in a ticking, clattering sound.  In human terms your car has "gas" and must pass it.  Usually this air passes after a short period of running.  Start and stop increases the chances, wrong weight oil, temperature, etc. etc.

If the above is done and the issue still presents you could have a lifter failing.