Re: 2001 Zetec slight ticking noise ???
If your fluid levels are holding steady and you're not consuming any oil between oil changes (half a quart or less is fine every 3K). Does the ticking noise appear only at idle, or under load (ie. highway driving)? Also, How many miles are on the vehicle? When was the last tune up performed?
I'd keep things simple first and try running a higher octane. If you run regular (87 octane) try a tank of 89, or even a few gallons of 91 and see if the noise goes away.
Upping the octane won't necessarily solve the problem, it'll just prolong it from damaging the engine/valves. I'd run some good fuel injector cleaner over the next couple months, rotating a bottle with every second full tank of fuel. Worst case scenario would be having to get a valve job done due to wear & tear. Once you've answered my questions above, I'm sure myself or others on this site will be better able to understand your problem a bit more and at a minimum, guide you in the proper direction.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!