I have a 2001 Durango with the 4.7 V8 engine that runs like new. Still has low miles(84K) for it's age. This week when we cold start it a loud noise on the passenger side starts up. It sounds like a large exaust leak to me. My wife thinks it sounds like a playing card in the spokes of a bike(thing we did as kids). After a moment of running, it goes away. I don't have any trouble codes either. Does 4.7 engines have EGR valves?
Any ideas? Thanks, Herb

 

could be the lifters (Lash adjusters) pumping up. when did you last change your oil? did you use a different brand of filter, some will let the oil drain back & you have a moment of pressure build time at cold start up. old thin oil will do the same.

Could be the start of an exhaust leak, cold start is very rich & will make more noise at a leak than after a few min of running.

Start it cold use a long screwdriver as a stethoscope. try to narrow it down.

 

it could be the adjusters running dry at start and ticking on you(normal issue on the 4.7 just wait till they stop then drive and you will be fine), but that would come from both sides of the truck, not just one

my guess it is the starts of an exhaust leak, and as the truck warms up the manifolds expand and seal the leak hence it goes away and you dont hear it anymore

 

next time you have a chance just start it up and look underneath for some holes in the exhaust line.

 

Exhaust leak.

 

Can exaust leaks be for just a short time and close up? Could it be something in one of the independent coils making a large noise for a moment? Dumb question being it has overhead cams, are there lifters on this engine? Wadda ya think? BTW, I changed the oil again last night and put some fuel cleaning additive in a full tank of gas. Thanks, Herb

 

When the truck's engine is cold it runs richer. at initial start up the extra fuel will go to the exhaust then pop when it hits atmosphere & ignites. once the engine management reduces the fuel ratio the noise will quiet down. this phenomenon is more common to manifold & head pipe leaks as the exhaust cools on it's trip down the system its temp drops below ignition point or excess fuel is catalyzed in the converter.

metal expanding due to heat will sometimes reduce a leak as well. you can probably still find it using a bit of hose as a stethoscope.

If it was a coil, you would have a misfire.

They're called HLA's hydraulic lash adjusters. they sit right on top of the valve assembly. they are in essence a miniature lifter, & their job is to maintain valve clearance. they do so by using engine oil pressure, just like a lifter.

When they loose their prime or pump up, it can take a moment at cold start for them to get enough oil volume to work & excessive lash is the temporary result.

 

Well the Moderator hit it on the head! Under the heat shield on the exaust manifold I found a rusty looking washer clanging around. It turned out that the top rear bolt broke off where the washer was suppose to be. This bolt is one of eight that holds the manifold on, then the heat shield bolts to the top of it using the top of the bolt only at a different torque. Hence I have an exaust leak due to the manifold not fully held down. Now to figure out how to get it out without removing the whole manifold. I'm hoping to maybe cut a slot in it with a Dremel tool and use a screwdriver as it's only like 24 ft lbs torque. Thanks for ideas. Hopefully this will also help others in the same boat(Car!)Herb

 

It is always a broken manifold bolt with that issue on the 4.7.

A search will show you 100s of threads with the same initial question, "now how do I get the bolt out" and 100 "oh that was easy, here is how it went" threads.

IndyD

 

I have the same ticking at start up..I also had a broken bolt..I had a pro remove the manifold, re-surface it, new gasket, new studs, etc. noise is still there..So, back to these lash adjusters..is there advice on replacement or adjustment on these things? what can be done to get rid of the this noise? There are literally 100's of thousands of Durango's and 4.7L engines out there it's hard to imagine that someone hasn't figured this out by now..any advise from the pro's?