Expensive sounding engine noises

There wasn't a reason for the engine to be hot? Preignition sound
and overheating is a head gasket.
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Jeff debit wrote:
>
> The last few months of driving my good old Cherokee with a 4.0 engine
> and about 300,000 miles has been making a bit of a clicking sound when
> the engine is cold. Tonight as I was driving along the clicking sound
> got a lot worse, and the engine was hot.
>
> As this engine has a BUNCH of miles on it I'm really afraid it might be
> a rod bearing letting go, but I'm hoping it might actually be a lifter.
> The noise is now always there, and it seemed to be getting worse as I
> drove, it is somewhere between a click and a clatter. The oil pressure
> is at least good enough the idiot light stays off, and of course the
> crankcase is full. Under moderate to heavy acceleration the noise goes
> away, it's always there under light acceleration and when cruising or
> idling.
>
> Is there a quick and dirty check? I seem to recall if you pull the
> spark plug wires off one by one and the problem really is a bad rod
> bearing it will quiet down when that cylinders wire is pulled, but if
> it's a lifter pulling wires won't make any difference.
>
> If it is the rod bearings what kind of luck have you guys had with used
> engines vs rebuilt. I have neither the money or the inclination to buy
> a new Jeep and plan to keep this one for as long as I can. (Well, a new
> Wrangler Unlimited with a hardtop would be really cool, but that's only
> going to happen if the Prize Patrol shows up!).
>
> Jeff DeWitt