Oh no...lifter tapping...I think

So I refilled my coolant and started up the car to bleed the lines and I noticed a chattering or tapping coming from the passenger side valve cover. So I had my dad listen to it while I rev the engine up a little from idle and he seems to think its a lifter too. How can I be sure and how do I remedy it?
I am NOT going to tear into the engine to replace a lifter if that's what you are thinking. Are there any external ways of fixing it? Thanks.

And is it bad to continue driving it like this for a little while?

So I refilled my coolant and started up the car to bleed the lines and I noticed a chattering or tapping coming from the passenger side valve cover. So I had my dad listen to it while I rev the engine up a little from idle and he seems to think its a lifter too. How can I be sure and how do I remedy it?
I am NOT going to tear into the engine to replace a lifter if that's what you are thinking. Are there any external ways of fixing it? Thanks.

And is it bad to continue driving it like this for a little while?

Over time, you will run the risk of a bent pushrod, a broken rocker arm, a broken valvespring, or a mushroomed valve end. However, it's not the be-all-end-all engine malady. Change your oil, using one quart of ATF in place of one quart of oil, and use a new filter. Run the car like this for one full tank of gas, then change oil and filter again, using all oil as you normally would this time. Don't be alarmed to see jet-black oil come out of the pan when you do that second change - the detergents in ATF will break up sludge and loosen deposits in the lifters.

I know my mechanic offers some type of engine flush service, would that do the same thing? I think it might be cheaper than buying 9 quarts of oil and 2 new filters. I actually just changed my oil when I installed my headers, about 100 miles ago...

The trans fluid as mentioned is a fair do-it yourself remedy that works quite often and keeps the money in your posket that would otherwise go to the mechanic. Give it a try :thumbsup:

Thanks for the advise guys, but I took it up to my mechanic and they found that its not a valvetrain problem, its still an exhaust leak. Apparently, the EGR tube that connects to the back of the passenger side header slipped out. During install, it didn't line up right, so I took a breaker bar and wedged them together. There wasn't enough room to fit the bolt in because the backside was up against the block, so I couldn't get a nut on the back of it. I thought there was enough overlap that they would stay together without it, but I was wrong.
I don't want to pull the intake manifold for block-off plates, so I decided to block it off at the tubes. What should I use to block both tubes off? I figured for the actual header, I could fab up a piece of something and bolt it to the pipe and just tighten it really tight. But what about the hose that goes to the manifold?