m_russell14

Good day to all! Very new jeep owner here and I have a question regarding a suttle knock that seems as if it is coming from behind my passenger glove box area. Does it while at idle/in gear/in 4x4/in 2wd. I can turn off the rig and restart and its gone. Any ideas? 150,000 miles. Runs strong and doesn't leak a drop of oil.

Thanks
Matt

That Jeep Guy XJMJ

the fuse for your gravitation puller is going bad so watch it on those flexy and steep areas of the trails...

m_russell14

My gravitational puller fuse? Wow. Thought this site was for help? Not sarcasm. The knock starts exactly 45 seconds after initial start-up. It sounds like it is directly under the passenger floorboard/firewall. If you are being serious with a gravitational pull fuse you are $*%**** with the wrong forum. That forum is located right next to your ken doll collection.

Now, if anyone can SERIOUSLY direct me I would greatly appreciate it.

Thanks,

Not a KEN DOLL.

winston427

Don't let it get to you. Unfortunately I do not have an answer either, but be patient and I am sure someone will be able to provide some helpful insight to a solution.

1jeepman

If it is behind the glove box then it could also be the circulation of water through the heater core. Just throwing out some ideas, never really heard of this before. Does it do it all the time or come and go?

1jeepman

BTW welcome to the forum from Ky.

m_russell14

Its like clockwork. Exactly 45 seconds after start-up. Cannot hear it in the engine compartment nor the Passenger wheel well. However, these things (4.0L) are pretty loud as they run normally I'm told.

I hear it increase in frequency with acceleration after the knock begins. I'm digging the help (sans the first one) haha. Thanks for any insight.

Matt

m_russell14

BTW Flagstaff, AZ

winston427

Ok, let's get more in depth with the knock description. Is it a metal on metal knock, plastic on plastic. How loud does it get, a light tap that progresses, stays steady, a loud thump, or a severe knock. This one has me intrigued.

1jeepman

Well i don't know, got me really stumped too. Wish i could hear though. I'm sure before the night is up somebody will really give you an idea as to what it is.

winston427

How long has it been making the noise?

m_russell14

Definitely NOT Metal to Metal. Nor is it a sewing machine knock like an Air cooled VW. Its a solid knock. Not a tick so to speak. You can only hear it when the radio is off. I'm not an **** veteran (although a veteran) but, I want to prevent anything else that can succumb from this. Ya know?

Starts EXACTLY 45 seconds after start. Cold start, warm start, start in Neutral (A/T).

m_russell14

Just started within the last week.

This heater core water circulation has me thinking too. When the wind shield defrost is on the RPMS kick up and down randomly. Other than that it is fully operational (Warm, Hot). Works great.

winston427

The only thing that comes to mind for me is a malfunctioning blend door in the heat/ac system. They are vacuum operated and a vac leak may cause it to cycle back and forth. They increase in knocking speed with the engine rpms could be due to the vac pressure increasing and decreasing as the engine rpms go up and down.

Have you noticed any problems with the airflow through the vents in the last week. Such as having the ac selector on floor and air only coming through the defrost?

m_russell14

No problems with the vents and the selected zones. All is working properly with the exception of the RPM's on windshield defrost.