4.7 issue...

[HammerZ71]

Not on a Ram, but I think this is warranted to put in this section.

The 4.7 HO in my Grand Cherokee decided to drop a valve with only 102k miles on it. So it's down and out at the moment. Don't know the entire extent of the damage, but cylinder 2 is obviously showing 0 compression. I've only pulled the valve cover at this point as I'm finding out how much of a bitch it is to get the head off of an overhead cam engine!

Reason I'm posting this here is because I NEVER heard of this being a widespread 4.7 problem UNTIL I POSTED ABOUT IT on another site and was astonished to see how many guys came out in that post that it happened to them. It appears that from '99 up until they re-designed the 4.7 in '08 that they were ALL susceptible to valve seat failure.

I'm finding MOST who have had it happen were up over 120k miles, but as I said, I have only 102k on mine. MOST guys report hearing a tapping (an obvious valve tapping) sound prior to total seat failure. With mine, I had no warning but luckily when the valve dropped I was idling so I'm thinking damage is at a minumum.

This is just a heads up for guys with a pre-'08 4.7. If you are hearing a valve tapping then you really need to check it out SOON. If you drop a valve you are looking BIG $$$ for repair, if repair is even possible, a couple guys report that the dropped valve resulted in irreparable block damage!

I'm also finding out that just like so many other common issues (can you say Hemi valve springs or 9.25" LSDs?) Chrysler has been aware of the issue almost since day one and did nothing about it! It's widespread enough that when I went looking for a re-manned replacement head (which was a bitch to find for an HO engine) that ALL the ads say "valve seat issue fixed on our heads".

Again, you may not get a warning tapping prior to failure (I didn't) but most guys do. So if your valves are tapping, be prepaired...

[BAD HABIT]

WOW, i have a small tap at start up, but it goes away with warm up, and seems to be the drivers side manifold gasket, cause thats where i hear mine. I hope and pray its not valve tap. im at almost 101k now. Good luck with that ed, and thanks for the warning.

[AWE Daniel]

Wow that sucks!

[HammerZ71]

Originally Posted by BAD HABIT WOW, i have a small tap at start up, but it goes away with warm up, and seems to be the drivers side manifold gasket, cause thats where i hear mine. I hope and pray its not valve tap. im at almost 101k now. Good luck with that ed, and thanks for the warning.

Yeah, I dealt with that one late last fall, back two manifold bolts were snapped on the driver's side. You need to fix that one sooner than later because a ton of guys who let that one go too long ended up with a warped manifold on that side and had a much larger bill on their hands than just two bolts.

I'm starting to get VERY disillusioned with the 4.7...

[HammerZ71]

Well I got the heads off this past weekend - only took me about 7 friggin' hours.

I'll continue this in the Jeep section where it should be - but I invite ALL 4.7 owners to keep up with it there...


http://www.semopar.com/showthread.p...2094#post52094