Lifter tick or cracked manifold?

Ejforan

Ejforan

TJ Enthusiast
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Washington state
This has been going on for a while now I just haven’t had the time investigate it. On start up the jeep makes a bit of a ticking noise but goes away once it is heated up. Doesn’t happen every time but it is frequent. It is a 1998 4.0 3spd sitting at around 130k miles and a seemingly stock manifold. I have read that the early model exhausts were too rigid making me suspect it is a manifold crack. Gas mileage has also been a bit low recently but I have only been doing city driving 20-40mph and getting 11-12mpg.
 
My 97 dropped into the teens on mileage before I checked the manifold... didn't hear any ticking. Replacing it did good things.

Have you visually inspected the bolts to make sure they are all there? Might want to get a wrench on em too and see if any are loose (preferably after it's cooled down a bit.)

What oil are you running and are you burning any?

Have you pulled the plugs and checked color, condition and gap?

-Mac
 
macleanflood said:
My 97 dropped into the teens on mileage before I checked the manifold... didn't hear any ticking. Replacing it did good things.

Have you visually inspected the bolts to make sure they are all there? Might want to get a wrench on em too and see if any are loose (preferably after it's cooled down a bit.)

What oil are you running and are you burning any?

Have you pulled the plugs and checked color, condition and gap?

-Mac
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I have not inspected the bolts no, until recently i presumed it was just lifter tick and wasn’t causing many problems. I am not burning oil just leaking a little bit using valvoline high mileage 10w30. I changed oil a couple times to different brands and pennzoil made it slightly louder. Plugs have been recently replaced with proper gap and it was happening before I replaced them as well. One last thing is my vent selector doesn’t switch to all the vents so perhaps the gasket is torn slightly somewhere. When I get a chance I will check on the exhaust bolts and also make sure it is a stock manifold.
 
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if Your losing mpg noticeably you may have something wrong. 11mpg city sounds pretty damn low if your Jeep is stock, but I’m no city boy so I have no idea what mine would get if I dealt with city everyday. The worst mileage I get is 15mpg with 35s 4.88s and a 5 speed.
 
Wtrask said:
if Your losing mpg noticeably you may have something wrong. 11mpg city sounds pretty damn low if your Jeep is stock, but I’m no city boy so I have no idea what mine would get if I dealt with city everyday. The worst mileage I get is 15mpg with 35s 4.88s and a 5 speed.
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Ive gotten as high as 18 while this was going on and I have still been getting my usual gas mileage since I got the Jeep at the 15-16mpg mark. The three speed may be making the difference because 45 mph the Jeep is the happiest for sure. 2k rpm in third gear and also when the torque converter locks it seems. I have 3.73s and 30x9.5 ko2’s. Does anyone else have experience driving in the city with a 32RH? The main mpg post mainly had manuals.
 
If you inspect the manifold while the engine is running, you might be able to detect whether there’s a leak. If you search around on this forum, you’ll find some clever tricks for doing that.
 
My manifold has made a ticking noise as long as I can remember since new basically. It quiets down after it warms up.
 
Wtrask said:
if Your losing mpg noticeably you may have something wrong. 11mpg city sounds pretty damn low if your Jeep is stock, but I’m no city boy so I have no idea what mine would get if I dealt with city everyday. The worst mileage I get is 15mpg with 35s 4.88s and a 5 speed.
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How in the world?.... I get 15 with stock 30in tires, 3.73 gearing and a 5 speed. That's with the soft top too! Maybe I have a heavy foot... XD
 
Wtrask said:
My manifold has made a ticking noise as long as I can remember since new basically. It quiets down after it warms up.
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Ok I an glad to here that. The ticking hasn’t affected me at all I just finally have time to research into it. A friend has also said he thinks he has heard an intake leak when I accelerate, I’ve never heard it so I presume its just the aerodynamics. Just for theories sake, lets say my gasket needs replacing. Would it be worth the 150 to replace the stock manifold with a dorman since I have the early model manifold? My thought would be it would be worth it.
 
Ejforan said:
Ok I an glad to here that. The ticking hasn’t affected me at all I just finally have time to research into it. A friend has also said he thinks he has heard an intake leak when I accelerate, I’ve never heard it so I presume its just the aerodynamics. Just for theories sake, lets say my gasket needs replacing. Would it be worth the 150 to replace the stock manifold with a dorman since I have the early model manifold? My thought would be it would be worth it.
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I went through this recently, and my notes are listed here (scroll down in that post).

Mine is a 2.5, but I think that what was true for me will be true for you too: you cannot find a true OEM replacement. You'll have to settle for an aftermarket one, or decide to go with headers. I went with Dorman.
 
SSTJ said:
I went through this recently, and my notes are listed here (scroll down in that post).

Mine is a 2.5, but I think that what was true for me will be true for you too: you cannot find a true OEM replacement. You'll have to settle for an aftermarket one, or decide to go with headers. I went with Dorman.
Click to expand...

You can still get an OEM MOPAR replacement for the 4.0. RockAuto has them for $483.79.

After going through two replacement aftermarket manifolds (with flex bellows) that cracked within a few years, I decided to pay quadruple the price for a Mopar one this time. Is it worth the extra bacon? I hope so. The Mopar manifold is a bit heavier with better welds and has a thicker flange. Plus it is made in the USA. :) I have had mine on since November, so time will tell.
 
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It's a TJ, you have a cracked manifold AND a lifter tick....LOL

To check the manifold, with it running and outside, pull the vacuum line off the brake booster and shove it into a can of Sea-Foam it'll smoke like hell, but watch the manifold and if it's cracked you'll see the smoke coming out of it.
Be ready to watch, no fooling around, it'll drink up that can pretty quickly.

Don't do it in the garage, you've been warned.
 
J.Pierce said:
It's a TJ, you have a cracked manifold AND a lifter tick....LOL

To check the manifold, with it running and outside, pull the vacuum line off the brake booster and shove it into a can of Sea-Foam it'll smoke like hell, but watch the manifold and if it's cracked you'll see the smoke coming out of it.
Be ready to watch, no fooling around, it'll drink up that can pretty quickly.

Don't do it in the garage, you've been warned.
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I used to be a GM dealership tech. I did this on a truck one time and filled the entire shop with smoke so thick it looked like an early morning fog on the Golden Gate Bridge. The other techs in the shop were not happy.
Transmission fluid works well for this, too. 🤣
 
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This is exactly what my Tj would do. It would tick on start Up and would go away after warming up and it was a leak in the exhaust manifold. It eventually got louder and stopped going away and that’s when I found the leak. Replaced manifold, fixed ticking.
 
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Winks42 said:
This is exactly what my Tj would do. It would tick on start Up and would go away after warming up and it was a leak in the exhaust manifold. It eventually got louder and stopped going away and that’s when I found the leak. Replaced manifold, fixed ticking.
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did replacing the manifold improve gas mileage?

I have a 2000 4.0 with the 32rh. I have the same ticking on start-up then goes away. It hasn't been high on my priority list. I typically get 14 mpg.
 
JC123 said:
did replacing the manifold improve gas mileage?

I have a 2000 4.0 with the 32rh. I have the same ticking on start-up then goes away. It hasn't been high on my priority list. I typically get 14 mpg.
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2000 - 2006 Jeeps with the 4.0 had a 2-piece exhaust manifold that typically do not crack.

Your ticking is probably something else.
 
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TJRick said:
2000 - 2006 Jeeps with the 4.0 had a 2-piece exhaust manifold that typically do not crack.

Your ticking is probably something else.
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I have a 2001 and it had the same symptoms - ticking, truly abysmal fuel economy and a definite noise. Turns out 2001's (at least the RHD versions) have the one-piece manifold not the 2 piece and mine was cracked in the usual spot. Shock reveal, turns out my inlet manifold was cacked too - one of the ports was broken completely off and RTV'd back into place but the key message here is that not all 2000-2001 Wranglers have the updated exhaust headers.
 
Thank you all for the responses. As of right now I will do a bit of inspection but for the most part leave it be unless it starts getting louder. I will update this if I find anything.
 
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