Questionhi, i have a hyundai accent, r 1997, with an engine tappet noise? i have done an engine flush on it with a new oil and filter to try and wash out the old oil, but the noise is still there, it sounds like tappet noise but is there all the time, but do you know of any other common problems with that type of engine, its a 1500cc 16valve. thanks luke.
AnswerThe only common issue I've seen causing tappet noise is sludging of the oil passages, causing insufficient oil feed to the hydraulic lash adjusters (tappets).
Presuming this is the same head used on U.S. 16v 1500cc engines, this design does not use rocker arms, so the passages for providing oil to the tappets are in the cylinder head. The advice below presumes the oil level in the engine is proper.
To make some determination about what is occurring, remove the valve cover. Then check each of the tappets to see if you can easily push down on it. If so, that tappet will make noise. You'll need to rotate the engine by hand every so often to be able to do this with all the tappets.
If all the tappets can be depressed, you have an issue affecting the entire engine, such as low oil pressure and/or severe sludging. If you test and determine the oil pressure is low, then it can be a lengthy diagnostic process to determine why.
If a few tappets can be depressed, then you likely have some significant sludging in some of the passages in the cylinder head. You may be able to blow it out using compressed air into the oiling hole in the head, but more likely, the head will need to be sent to the machine shop for hot tanking or be replaced.
If you have only one tappet noisy, it's possible you may simply have a defective tappet. In this case, replace the tappet and recheck.
