98 2.5 adjustment

[Nightshade]

So I have a 98 Mazda b2500, the motor 2.5 is not really noisy but it does have that tick or chatter to it not really loud and I know this comes with any 4cyl. But my question is for an engine that has been taken care of and not abused at 183k miles would it be safe to say it's time to have the valves adjusted ? Or maybe run a different oil or an additive between changes ? It doesn't burn oil or blow it out or use any for that matter.

 

[tomw]

There is no valve adjustment possible. The cam uses hydraulic 'supports' that do any necessary adjustment. If the cam followers are making noise, either the bits are worn out(unlikely) or the lifter/supports may be gummed up or stuck.
You can remove the cam cover, and pry the followers out of place and then remove the supports. Once remove, you can either replace them or clean them at your discretion.
Most times they work without problem for the life of the engine.
The 2.3 version is noted for having a loooooooonnnnnnnggggggg life, and 300k is not unheard of. You might want to check that you have a good oil supply, your pressure is good, and your pump working. You can access the oil pressure via the port on the drivers side of the cylinder head, rearward. Get a mechanical gauge, connect it, and observe what your pressure is doing before doing other things.
tom