thanks, but will this cause the metal in the pan?

 

Yes, I would say that you have your smoking gun if it proves to be a main/rod bearing.

Folks, please do not "flush" your engines with anything. If you've been maintaining them right, they won't need it and if you haven't, you're basically hitting a hornet's nest with a baseball bat...or playing Russian roulette...your choice.

Dave

 

The above is the whole reason I install a new quality filter before doing any kind of flush. The flush was also after running synthetic for 6 months, which will break down sludge as well, only slower.

I agree with Dave on the flushing. It is risky, and sometimes it uncovers problems. Just switching to synthetic IMHO is the best route.... unless you know how to work on an engine.

John, you never answered my tap or knock sound descrition...

 

I did use a brand new k&n oil filter for the flush. idle for 20 minutes. the sound is still more of a tapping then knocking, but i have listened to all the lifters with a steth., the exhaust, each exhaust bolt, the intake, and the noise is not present except the block between the starter and the block.

 

which is right by your cam, which the lifters ride on. A tiny piece of junk can get into the lifter and cause it to leak and collapse. I think your tick is a lifter and you just happened onto the main bearing.

 

maybe, i can see if the metal is ferrous. if it isnt then that would pretty much tell me it is a bearing wouldn't it? it seems to me that if a lifter is tapping, i would hear it clearly at the top of the engine. i can hear every lifter well, some are noisier than others, but none are making that noise imo. but we will see! i plan to take pics

 

A lifter knock will have a frequency that is half crankshaft rotation speed. A rod or main bearing knock will have a frequency that is the same as the crankshaft rotation speed. The difference is usually pretty easy to discern given this distinction, especially at idle. In other words, a rod or bearing knock will happen twice as often as a lifter tap. With this info and the magnet observations, let us know what you find.

Cheers,
Dave

 

How bad is it to drive with lifter tap?

 

This is also why i do not recommend a ATF engine flush, if it aint broke dont fix it.
Full synthetic motor oil has at least twice the detergants as conventinal motor oil and will slowly and safely clean your engine while you drive as long as you dont go 15,000 miles between oil changes.

If you do not know how well your truck was maintained then dont worry about it and just start from scratch like nothing has ever been done to it.
Full synthetic motor oil at 3,000 mile oil change intervals for the first 2-3 oil changes will do wonders.
Then you can go to every 5,000 miles with full syn.

 

You can drive forever with lifter noise.