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Exhaust Manifold/Intake Gasket leak or crack? VIDEO!!!

JoJoDaKilla

NAXJA Forum User
Location
Oak Ridge, TN
Okay so when I got this Jeep the tick was mild and not a big deal. Its a 1990 Jeep Laredo 4x4 Automatic. Now its just getting annoying and it just feels like Im losing power and gas mileage possibly. I was told by previous owner who is my friend, that the dealership just said it was the gasket and that they just tightened the bolt to make it a bit quieter. So if you guys think you could listen and see if you agree that would be great. I know my Jeep is a bit loud but you can still hear the tick and its going up a hill. Thanks you guys have always been great here at NAXJA!! I know another guy below me had a crack, just wasn't sure if his made any odd noises with it. We have no emmisions here at all.

http://www.youtube.com/watch?v=FXxpFwUtrvE
 
do you know where the leak is? Shoot some WD-40 (the new non flammable kind) at the leak while its idling, or all along the gasket. If there's a vacuum leak, it will get sucked in and the idle will drop. Time to replace the gasket. You could try tightening down again, probably wont help.
Also check the header thouroghly for cracks along the joints. They usually crack in 2 places; where #4 header tube joins the horizontal tube (this one is very difficult to see with the intake manifold on), and the second place is where the 2 header sections meet at the Y (visible from underneath the Jeep).
 
If the tic goes away after the engine gets hot then its a crack in the E.M. (if its cast iron) when metals cold it shrinks (leaks) and hot expands and will close the crack..
check the back (closest to firewall) two bolts on the header too as it is known to break..
then try the replacing the gasket at the end of the header pretty cheap to try..
 
Just get 3' of vinyl tubing, 1/2" ID or less, stick one end in your ear, move the other end around the manifolds until you locate the source of the "tick".

If it is a cracked exhaust, and as you have a Renix with EGR that can limit your choice of replacement exhaust manifolds--the replacement has to have two bungs, one for the EGR tube, one for the o2 sensor. You can modify, or have modified, the 91+ manifold by welding in two bungs.

The vinyl tubing is the poor man's stethoscope, really good for locating noises.
 
I will try the WD40. Sounds interesting to do. And when the vehicle
really warms up it gets louder, so I was thinking crack in exhaust manifold. I just wasn't sure if the ticking is part of the cracked exhaust manifold or not. I would like to do it all myself to repair but all the write ups are for newer 4.0s and my intake area looks completely diffrerent with alot more wires and hoses eveywhere.
 
another good check to see if its your E.M. is seafoam. follow the directions, and watch for smoke from the engine bay, staring at the E.M.

Doesn't sound like exhaust, but im no expert
 
It really doesn't sound like exhaust either, I'm just going with the tick kind of sound. It's sort of like a tick at first but after it's really been driven for awhile it's more like a loud puffing sound if that makes sense. I did seafoam it and it was coming out of the engine bay from the back. Would that say cracked exhaust manifold or could it still be a gasket? Funny thing with seafoam was mine started smoking during the pour in time. Not 10 minutes later, I thought that was weird.
 
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