Looking at "ticking" MJ

[GreenF350]

So this weekend I'm going to look at another 91 MJ. Over the phone, I was told it makes a slight "ticking" sound, and that he was told it was possibly the flywheel. I'm guessing a small crack could cause this, but I wanted to ask if there were any other obvious things to check. I know its hard to diagnose without me actually seeing the truck 1st, but hey, u never know. Either way, Ill update once I look it over. 4.0, auto, 4x4 etc....

[mkbruin]

As we all know, the ticking is usually just the exhaust valves...

 

There *could* be additional mechanical issues though

[dasbulliwagen]

A cracked flex plate would be much noisier than just a ticking.

[mkbruin]

any other details? Mileage? Powertrain?

[KYMJ]

The valvetrain for certain.

 

But also check the harmonic balancer for seperation and the rubber between the 2 pieces may be sticking out and hitting something(don't recall). That happened to me and produced a ticking noise.

[91coMANche]

I've seen cracked manifolds cause ticking but that usually goes away when the engine warms up.

[Geonovast]

First step to diagnose where a ticking may be is pretty simple.

 

Start it up and let it idle.

 

Take the oil fill cap out and watch one of the rockers.

 

If the ticking is the same speed as the rocker's movement, it's a valvetrain noise.

If it's twice as fast, it's somewhere down below.

If it's neither, it's probably not internal to the motor and could easily be something that's spinning outside the motor (i.e. fan) hitting something.

[M1A1TankerTom]

I would put money on it that it is an exhaust leak...either cracked manifold or bad gasket. Trust me our comanches are prone to these problems and will make a very loud ticking noise, guess how I know :(

[jimmy21669]

I had a ticking that was related to the clutch before. Bad throwout bearing. But when the clutch was depressed it would go away.

 

When you check out the truck...see if it goes away when you press the clutch (or changes at all)

 

Usually it is a small crack in the exhaust manifold. To see if THAT is the case, get the truck hot and see if the sound lessens as the exhaust expands (closes the crack).

[GreenF350]

Thanks for the replys. The seller, however, is now not answering the phone, and the add for the jeep has since been taken down, so I think I know what that means. Too bad too, because this is the second MJ in 2 weeks Ive missed by a day before I could check it out. I really want another MJ :fs1: