Hey everyone. I am new to the site, and yes I did do a search, but was unable to find a specific answer to my question.

I just purchased a 2007 Ram 1500 (5.7 L Hemi) and of course, as soon as I take it home, let it set, and fire it up in the morning, the first thing I hear is a knock. It is coming from the bottom of the engine. It will stay like that until I drive it for a while, then goes away.

I do have a warranty on it, but was just curious if anyone knew of this happening to them so I could get an idea of what to talk to a mechanic or dealer about before I take it in.

Thanks for the help...Again, I am new to the dodge scene and already am happy (except for this little issue)!

 

Prob not a knock. it's prob the notorious "Hemi Tick" and maybe just quiets down when it's warm. I've had it since 400miles

 

Oh, its a definite knock. I hear the hemi "tick"...this is different. This is a knock, knock knock....sound.

 

The service dept. manager had told me that some of the Hemi's were experiencing wrist pin noise. Floating pins can make noise, but enough for a knock? Sounds a bit excessive to me. But I haven't torn down a 5.7 yet.
My 4.8L Cheby made a racket upon start-up. They claimed piston slap and lifter tap on top of it all sounded like a bunch of rocks shaken inside of a coffee can for the first 3 or 4 sec. i say bad flowing oil pump.

 

whos there?

 

^^^^^

 

Is the knock 1:1 with rpms or less? Are you sure it is coming from the bottom of the engine? When I bought my truck it had a lazy lifter... it would be a loud knocking sound on start up but would go away after 1 min. Lifter may have had something cloggin it up and it would collapse after you let it sit, and not fill up right away when you start the truck and it would make that noise. It went away after 10-20 starts, the lifter cleaned itself out.

Also if it only does it on some start ups it is most likely a lifter. They drain much more quickly when the truck is shut off so that the firing order has compression on the lifter. If the truck it shut off while the bad lifter has little to no cam/push rod compression on it, it may not knock at all when you start the truck.

Hope that helps.

 

Wingnutz, what vehicle do you have? that should be a requirement. Everyone should have to fill out the model/year of their truck.
LJBrown has an 07. Highly doubtful something is clogged already in a lifter. That sorta thing takes times to accumulate and cause issue's. More so with vehicles that have been sitting for long periods of time or older engines that don't get frequent oil changes. Not on a 2 model year old vehicle with low mileage generally.

 

I have an 06 with 33k miles. All it takes is alittle bit of sitting time to get stuck up... it will most likely work itself out shortly.