I apologize in advance but I have not yet taken the time to do much investigation of where this new sound is coming from. What I am hearing is a tapping sound similar to a rod knocking but is more of a soft knock rather than the sharp tapping I have encountered with rods in the past. I can't even say at this point that is on the bottom end. I noticed it when I was out driving and noticed it was still there when I sitting still with the engine idling. I notice the sound does accelerate with engine but doesn't seem to get louder, only faster. I checked the oil and other fluids yesterday and everything was at its proper level. The oil doesn't even look dirty. I had been running mid-grade gas but switched to running premium for obvious reasons. The sound started after I switched fuel. Could the 2 be related?

Thanks for all your help for this and my previous questions.

 

Try this, with the engine idleing put your hand ontop of the alternator, when the bearings go bad they can sound like a rod knock, thats what happned to mine in Jan.
When I put my hand ontop of the alt I could feel the knock. Removed the belt the noise went away. Spun the alt by hand and guess what...knock.

 

I will give that a try as soon as I wake up in the morning. Now if you could just help me out and explain what an alternator is and where to find it I think I can get that done. Just kidding. I'll let you know what I find.

 

DUDE! Dont scare me like that! lol

 

With the engine running, put your index finger between the belt and a pulley and the belt will lead you to the alternator

 

OK. Did some more investigating this morning I have pretty well ruled out the alternator as the source of the sound. I am also about 99% sure the sound is coming from the top end of the engine on the driver's side. It almost sounds like the valves may be just out of adjustment but it's only the one cylinder bank from what I can tell.

 

Ever done the ATF engine flush ???

 

I have not done much with the truck since I bought it 3 months ago. I was not given any maintenance records with the vehicle so I am assuming that nothing like that has been done. How do I do that and what would it accomplish?

Thanks
Tom

 

ATF is a very powerfull cleaner and will clean the whole inside of the engine,even up on top, like gummed up valves and such.

.Drain the oil
.empty and re-installor change oil filter ( I did the first, but would suggest the later)
.fill with 6 quarts of ATF (cheap one will do)....just in case...ATF stands for automatic transmission fluid
. Start the vehicle and let idleCAUTION: the vehicle has to stay immobile and should not be driven or put under load.

2 options

1. let the vehicle idle for 10 minutes. If wrong someone correct me please for I did the BMW tech one (#2)
2. let the vehicle idle for a minute, then rev at 1500 r.p.m for a minute and vice-versa for 10 minutes.

.Drain the atf
.change the oil filter
.fill with your oil of choice
.For 1000 miles,be easy on the go pedal. thendo another oil change to make sure you get rid of any left over ATF.


This helped me get rid of an engine tick.

 

Kind of sounds like just what my truck needs. I'll have to wait until I gat the truck back to Denver where I have the ability to change my own oil. Thanks for the help.