2004 Jeep Grand Cherokee V8 4.7 L. Clock from right side of engine immediately after starting engine. Seems to be in rhythm with engine and increases in frequency as I rev. Gradually subsides over first 5 minutes and not audible after that. Recent small leak of transmission fluid, but I’m thinking that has nothing to do with this. Thoughts?
I’d bet lunch that it’s a failing lifter. Your engine uses “hydraulic” valve lifters. They basically fill with oil when the engine oil pressure builds up to self-adjust and maintain proper clearances between the mechanical pieces between the cam lobe and the valve stem. They can get gummed up and begin to take a moment to fill properly.
I’d recommend getting it looked at and repaired before it gets worse. Constant hammering on the cam lobes is not good for them. Best thing is to buy a “pack” of new ones (they’re sold that way) and replace them all.
The best way I can describe it like a baseball card in the spokes of a bike.
Wondered if it might be a valve cover, hadn’t thought of a lifter. Thanks for the tip, I’m taking it in today.
You’re very welcome. Sincere best.
Check to see if there is any valve adjust that can be done. The 4.7 L Chrysler motor has a valve adjustment regime demonstrated on utube so I am not sure they are self adjusting.
Another possibility . . .
You have an exhaust leak on the right bank
When the metal heats and expands, the leak goaes away, to some extent
Check for a cracked manifold, as well as broken exhaust manifold bolts, studs, or leaking flange gaskets
This is a common failure on some engines
According to mechanic, lifters are fine. They are checking manifold gasket and manifold for a crack. Also looking at a leaky water pump and transmission pan. If a cracked manifold, I’m looking at an engine rebuild, right?
No. If you have a cracked manifold, then you just need a new manifold. It’s an external part and no big deal.
Somewhere around $600-700?
could easily be just the manifold gasket. no big deal for a shop,
Leaking/warped exhaust manifolds on the 4.7L engine in not unusual.
If I remember correctly it’s also not unusual to have an exhaust manifold bolt or stud broken off in the head along with the exhaust leak.
I agree with @asemaster. At the moment, I have a GM truck in the shop with several broken exhaust manifold bolts, on both banks
It’s got the classic symptoms:
Ticking noise at startup, diminishes as the engine warms up
P0171 and P0174 lean codes, due to the exhaust leak