Yesterday my car had its 35k PMS at the casa. Going home, a tak tak tak sound came from the top part of the engine. The sound would increase along with revving the engine.

This morning, the sound was still there. I called my service advisor and had him listen to the engine. He said they will come to my house to check on the engine. When I turned on the engine again the sound was gone.

Last PMS (30k) was AUG 13 using fully synthetic oil. The car ran 5k to 6k at the most. I opted NOT to have flushing and treatment for the 35k PMS. Possible scenarios according to my friends:

1. Tappet sound only

2. There was a sludge and oil did not go up the engine resulting in the sound. Natanggal sludge so the sound went away.

3. Dumulas mounting and went back to proper seating

4. Oil pump problem

Check engine oil did not light up. WTF could have happened when I just had my PMS? My car is out of warranty so I am really worried. I am hoping for the best case scenario according to Archie which is the tappet lang.