The valve train in my 1997 Caravan with 3.8L engine is making a "tapping" noise and seems that there is no oil going up to the valve train. It is a constant noise and the "tapping" goes faster when I rev up the engine. Yesterday, the service engine soon indicator illuminated. Any ideas?
StandOnCliff
09-02-2008, 04:08 PM
Thats usually a sign of a weak lifter. The service engine soon light coming on means it has found a problem. Read those codes and post them here. Turn ignition key ON-OFF-ON-OFF-ON as fast as possible. Your check engine or service engine soon light will begin blinking out two digit codes. As an example. It will blink once, then pause, then blink twice. That is a code 12. Blinking five times, pause, then blinking five times again is code 55. These two codes you will usually get and are no problem. Any other codes are a problem. Code 12 is battery recently disconnected and code 55 will be seen as the last message,it means end of message.
brooks_1615
09-03-2008, 06:55 PM
I am not sure if I did the On-OFF sequence correctly but the codes I got is 122155. Does that number make sense?
TomQuick
09-04-2008, 12:10 PM
According to the stickies, code 21 is a problem with the O2 sensor (neither rich, nor lean condition detected by sensor).
StandOnCliff
09-04-2008, 04:12 PM
That is right code 12, code 21 and code 55. The only one to worry about is the code 21. You have an Oxygen sensor bad. Question is which one. The self diagnostic test can't tell you which one is bad. An ODB 2 scan tool can. If you can't get one or don't wish to take it into the shop to be put on a computer, all you can do is randomly change all of them. Autozone sometimes does the checking for free if you have one around. Usually the one that is closest to the engine is the first to go, I would start with those ones. Oxygen sensors are recommended to change at 100,000. The tapping noise could be just low in oil or in need of a oil and filter change.
