On Feb 3rd I cut a corner short and dropped in a snow covered hole with the passenger rear tire. I kept going, didn't get stuck or stop. A few seconds later there was a tap/knock in the engine area. There was no loss of power and no miss in the engine. Oil pressure remains at its usual place around 40.
We got to checking things out yesterday afternoon and the tap/knock is can be felt in the purge solenoid on the firewall. The plate between the engine and tranny seems to be okay. The noise can be felt in the oil pan as well as heard in several places on the engine.
Our next thought is to pull the valve cover and check the rockers.
I should mention that this Jeep has over 173,000 miles on it and appeared to be "abused" before I got it almost 3 years ago. It also has an oil leak we believe may be the rear main in the engine.
Any suggestions would be helpful.

 

Took it out today and Oil pressure is running from just under 30 at idle to almost 50 under load.

 

mine

 

Mine always had a rattle on start up that went away when the oil got circulated.

 

If you're looking for reassurance that this is normal. .. you'll have about 500 positive posts.. especially for omega people who live with the white stuff. .. the peeps from Arizona and Florida have different issues... usually overheating.
This is the reason. I have an auto starter. To let it warm up a bit while I get dressed for work. Circulates the oil, makes my baby happy.

 

And yes... sometimes I have to autostart it twice. It's old. Maybe the battery, maybe the juice the starter pulls.. etc.

 

yep, from what I understand that's pretty common on 4.0s

 

I understand some noise is normal but there is a new noise that started a week and a half ago and wondering what it could be.

 

At different times it sounds different....a loud tick most of the time...sometimes a vaccuum leak....sometimes metallic noise......

 

My guess is that the big bang on the vehicle gave you a small exhaust leak at the manifold to block, or at the header. They change in sound depending on temperature. It will often sound like tick, sometime metallic, sometimes not. Its just a guess, but if it started right after your vehicle got pounded and the motor and exhaust got jolted, its a reasonable guess.

Now you said you could feel it in the purge solenoid. You can probably disconnect the solenoid to rule that in/out as the source. But if you feel the tick through the oil pan or valve cover, I'm doubtful its the purge solenoid. At least in my experience, it isn't that powerful of a tick to resonate like that. But test it if you aren't sure.

 

A vacuum leak in the rear was also suggested

 

can you post a video of the sound?

 

Well, the sound got quieter when we change #3 spark plug...it was corroded and so was the boot. The vibration in the purge solenoid is now gone.
I'm wondering if you can just change one boot or do you have to change the whole stupid bar....

 

You can change one..

here

http://www.partsgeek.com/vm8jgk6-jee...+Coil+Boot+Kit

 

How hard of a job is it?