I just changed the oil to Mobil 1 clean 5000. It is not a synth oil but has 16% more cleaning ability (accordng to Mobil ). I also am using 5-30W since that is what the Durango manual says should be used on the 4.7L engine that I have. I plan on running this oil for 1000 miles and then changing over to full synth Mobil 1. I don't know that this will make a difference in the valve knock when the engine is cold or not but should provide more protection in the long run.
After the engine sets for about 2-3 hours I can hear the valves/lifters knock for about 1-2 sec. on starting. This has to be due to all of the oil draining from the top end of the motor. I do not hear anything like this if the engine is warm and has been run.
I have also been looking at a 'pre-luber' unit. A pressurized tank that fills with oil. When you start your engine you fist only turn the key to the pre-ignition for 5 sec. This allows the valve on the pressurized oil tank to open up and flow oil through-out the engine before starting. This might work but finding a place to mount the unit might be difficult. Plus I would like to get other peoples opinions on this before I get one. Ever heard of one ??
http://www.autoenginelube.com/

 

Did you ever install the pre-Luber??

 

I ordered one. It should be here sometime next week. I should have it installed in about 10 days or less and I'll post an update. Thanks, Mike

 

Yeah let us know how that works out. It's a pretty ingenious idea. Also I could've told you to try some Lucas oil stabilizer that stuff sticks to everything in the engine. It would take quite a while to drain off.

 

Yes, I did quite a bit of research before I bought this pre luber. I just did change my oil about 3 weeks ago to Mobil 1extended and one quart of Lucas Oil synthetic. Still have the problem. If the truck sets for longer than about 1 hour I can hear the upper valve train rattle when I start the engine. Only lasts for about 1 sec or so but I don't like it and it can't be good in the long run. Most likley I am getting some wear on some of the valve train components and the oil is not hanging in the lifter journals like it used to or something. Its only got 85K on it which is not that much on todays engines.
If the luber thing doens't fix that problem at least it will still be better for the engine, but its ~$600 too.
If I continue to hear the rattle I'll take it to a Dodge dealer, let them listen to it just to get their opinion. I called the dealer a few weeks ago and he said they had never heard of a 4.7L with valve train rattle on start up.....
Mike

 

My 4.7L does the exact same thing. Knocks only on start up for 2-3 secs only when cold. Let me know what fixes your problem.

Thanks!

 

Guys:

Agreed that although injectors can be noisy, the noise usually does not go away once it starts.The early 4.7 motors did have some issues with oil pumps failing, Could be that the pump is worn inside allowing oil to run back into the pan.

Also, please recall that the 4.7 is an OHC engine, and does not have lifters per se, but more like tappets that operate the valves directly from the cams. I do not believe there is a timing chain issue. The 4.7's chain is designed to last the life of the motor.

Metricman, do you have any info on how the previous owner took care of the truck. Maybe he/she did not change the oil properly and thus you have some bearing wear that would not normally be present.
How is the oil pressure when hot and when first starting. My bet would be that your pressure takes a second or two to come up, an whe it does the knocking goes away.

Don

 

Check your oil pressure next time you start it. See if for a second you have none, then it goes to normal and at the same time the knock is gone.

 

Nothing like a full year between old and current posts.

4.7s have a slight piston slap on startup. Run some SeaFoam in the oil, fuel and through the TB via the directions on the can(s). After the tank of fuel is gone, change the oil, plugs, etc. Use a GOOD oil and filter. If it is still there, not a lot you can do for it until she blows... if she ever blows. Doubtful.

IndyDurango

 

My 2002 4.7 had the same knocking problem. I tried using different oil filters, full synthetic oils and still the same problem. Ultimately what happened was that I now useCastrol 10-30 Syntec blend (part synthetic). Haven't had anymore problems since.