engine tapping ...oh no

[Y33TREKker]

Are you sure it was a mechanical tapping and not an electrical snapping? Maybe something in the ignition?

[IndianaVX]

well, does the coil pack make any tapping noise??? i mean im pretty durn sure it was mechanical, but ive never dealt with these coils over plug setups..... i suppose it could be a rapid snap snap snap snap noise. also, when i started it up this morning, i heard the slightest of rattleing of sheet metal. dont think its related, but i dont know. havent been home again since this morning to check it out.....
thanks guys, ill keep answering if you keep asking....

thanks again,
david

[Tobert]

It could be valve adjustment. Mine taps like crazy, especially on lighter weight oils.

[Y33TREKker]

It could be valve adjustment. Mine taps like crazy, especially on lighter weight oils.

I was just throwing out ideas with the electrical snapping idea. I guess I had just assumed that the 3.5L VX motor used hydraulic lifters, but I see from the cd manual that a solid lifter bucket/shim type adjustment is used, so valve adjustment could very well be the cause.

How many miles on the engine? VX valve adjustment intervals are every 60k miles.

[IndianaVX]

just rolled 63000..........

[Ldub]

Check your exhaust system to find the most likely cause of the sheet metal rattling sound...the heat shield(s) are a known culprit.

[Joe_Black]

If you have a Harbor Freight nearby you can pick up a mechanic's stethoscope for about $6 which can help isolate the source of the sound. You can also find them at NAPA and other auto parts houses for a little more.

If the sound is coming from the head then it's likely the hydraulic valve-lash adjusters, which have a published known-issue of sticking from varnish build-up. The typical "fix" is the use of 0W-30 or 5W-30 Mobil-1 which will remove the varnish over a period of time. The adjuster could also be failing (unlikely at your mileage, but possible), which in a worst-case scenario would cause very rough running as the affected valve stuck open.

Ldub's exhaust shield clatter is another valid possibility, and a while back Johnnyapollo had a noise that would only happen while in drive that turned out to be the exhaust making contact with the right side suspension link.

How long have you had your VX and been using Mobil-1?