Jeep question

[Chuck52]

This is the only discussion group to which I belong....a fact I am rather proud of. And since just about any subject seems to be acceptable for discussion, I have a jeep question. I'm going to Florida to pick up my Navy son's '97 Jeep Wrangler Sahara before he ships out for a six month pleasure cruise. He just informed me last night that the new exhaust manifold I thought he had installed is actually in the back seat, where it presumaby does little good./w3tcompact/icons/eyes.gif The manifold on the Jeep is cracked; apparently a common problem for this model. One of my buddies has a horror story about driving a car with a cracked exhaust manifold. Seems the crack allowed cold air to come into contact with hot metal where it is not supposed to, and cause severe engine damage. My son has driven the jeep for a few months with the crack with no problems, but he's in Florida. I will be driving it to Missouri. His mechanic friend says there should be no problem except for a bit of noise and maybe slightly worse, or maybe even slightly better gas mileage. Anyone got experience with this stuff? I know crackpots, but have no experience with cracked exhaust manifolds.

Chuck

 

[Jeff396]

I'm no mechanic, but wouldn't a cracked exhaust manifold just cause hot air to blow out...not cold air to be sucked in. I had a friend in the 70's who drove a company van for his dad's business. Thing ticked all the time with an exhaust leak resulting from a gasket problem. I don't think it caused any problems other than being very annoying. Can't be too much different that a hole in the muffler or header pipes. Now if it were an intake manifold you'd be messing up the mixture and may in fact cause problems. Anyway, just my opinion.

Jeff

 

[RobertN]

Probably the worst you'll see is a lean condition on the cylinder next to the crack. It may throw off the computer and fuel injection system, sense the Exhaust Gas Sensor is down the exhaust pipe from it, depending on how bad the leak is. I know here in California, they pick stuff like that up on the smog checks, and most of the time it causes them to fail the test.

You may actually get worse mileage, because the computer will try to compensate for the lean exhaust condidtion.

If you run it, be really careful about the fumes. You don't want to be on a long trip, smelling and inhaling the fumes the whole time, especially with the windows rolled up and all. People die from smelling to much of the exhaust...

 

[Chuck52]

Thanks for the replies. I think my buddy's problem occured when he shut off the engine and cold air came in through the crack hitting surfaces which would normally be protected while they were hot. That's how his mechanic explained his engine damage anyhow. Sound possible/likely?

I will be doing pretty long trips to get it from FL to MO. Stopping in Tennessee to see the folks and then continuing after a day off. However, it has a rag top, so I expect to have plenty of ventillation. I'll be aware of the carbon monoxide problem, however. Thanks for the reminder.

Chuck

 

[Jeff396]

Assuming it's a four, how hard would it be to take some tools and swap it out? Being that it's so new and that it's spending time in the south, it should come out easily. If it's a V6....forget I mentioned it. Maybe there's someone local who would be willing to replace your part if you explain the situation. Exhaust manifolds are not exactly tough as long as it's not one where the engine has to be lifted a bit to remove it.

Jeff

 

[Chuck52]

It's a six. I haven't looked at it, but it sounded like it wasn't easy to get to. Does it require pulling the engine?

Chuck

 

[s1120]

That would be an inline 6 in that. You will have to take the intake off also. I don't think you would need to pull the motor. Not that bad of a job.....unless the studs snap/w3tcompact/icons/frown.gif

 

[RobertN]

It's not particularily hard, but it's not really simple. It sounds like your tools and garage are two days away... which would complicate things...

 

[Chuck52]

Yup. I plan to drive it back to the great state of Missery with the cracked manifold. That was the purpose of my original post....to see if anyone thought that would cause engine damage. I'll probably pay someone to install the new manifold when I get it back here. I just spent a pleasant day working on both my old F150 and my Dodge Caravan, reminding myself why I didn't become a mechanic.

Chuck

 

[Jeff396]

I agree, a cross flow head with the exhaust on a side by itself could have been done with a few hand tools. However once you get into the intake side on a reverse flow head it's hard to anticipate what you would need before hand. Sometimes you need special tools as space to get to some of the bolts can be tight. Does your son know anyone who lives there and could maybe give you a hand? Maybe there are some TBNers in the area that might like to lend a hand fixing a Navy kids car. I love to do jobs like this on other peoples cars...especially since it doesn't cost me anything./w3tcompact/icons/smile.gif

Jeff