99 a bad year
Thread Starter
Junior Member
Joined: Jul 2011
Posts: 47
Likes: 0
From: NY
Year: 1995
Model: Cherokee
Engine: 4.0
I could of swore i read in here somewhere that 99 xjs had a bad motor in them. If someone could fill me in that would be great cause i am about to by one, seeng how my 95 got washed away in a flood.
Seasoned Member
Joined: Aug 2010
Posts: 358
Likes: 3
From: Illinois
Year: 1999
Model: Cherokee
Engine: 4.0
I thought '99's are a good year for XJ's. They got the improved intake and they were the last year for the 0630 cylinder head, although it seems to me that late '99's might have gotten the 0331 head and the new ignition system. If I was buying one, I'd look for the earlier although I'm not sure that the 0331 head is a deal breaker if everything else looks good.
CF Veteran




Joined: Nov 2010
Posts: 5,840
Likes: 117
From: In the middle of Minnesota!
Year: 1999
Model: Cherokee
Engine: 4.0
IMHO, 99 is probably the best year. Yes, I'm a little biased as I own one, but I've worked on all years and would buy another 99 or a 98 in a heartbeat.
While I have heard that there are a very rare few late 99's with the 0331 head, I've never actually seen confirmation of this and have asked in a couple of threads. However, all of the 00-01 4.0 engines have them.
Easy enough to find out though. Take a rag, wipe the area of the lip of the head about halfway back on the drivers side. With a light, you will be able to read the casting number on the head. The 99 should have the 0630 cylinder head, which is a very good head.
While I have heard that there are a very rare few late 99's with the 0331 head, I've never actually seen confirmation of this and have asked in a couple of threads. However, all of the 00-01 4.0 engines have them.
Easy enough to find out though. Take a rag, wipe the area of the lip of the head about halfway back on the drivers side. With a light, you will be able to read the casting number on the head. The 99 should have the 0630 cylinder head, which is a very good head.
Last edited by tjwalker; Sep 22, 2011 at 07:41 AM.
Seasoned Member
Joined: Sep 2010
Posts: 275
Likes: 0
From: Maryland
Year: 2004
Model: Grand Cherokee
Engine: 4.0L
IMHO, 99 is probably the best year. Yes, I'm a little biased as I own one, but I've worked on all years and would buy another 99 or a 98 in a hearbeat.
While I have heard that there are a very rare few late 99's with the 0331 head, I've never actually seen confirmation of this and have asked in a couple of threads. However, all of the 00-01 4.0 engines have them.
Easy enough to find out though. Take a rag, wipe the area of the lip of the head about halfway back on the drivers side. With a light, you will be able to read the casting number on the head. The 99 should have the 0630 cylinder head, which is a very good head.
While I have heard that there are a very rare few late 99's with the 0331 head, I've never actually seen confirmation of this and have asked in a couple of threads. However, all of the 00-01 4.0 engines have them.
Easy enough to find out though. Take a rag, wipe the area of the lip of the head about halfway back on the drivers side. With a light, you will be able to read the casting number on the head. The 99 should have the 0630 cylinder head, which is a very good head.
CF Veteran
Joined: Jun 2009
Posts: 2,173
Likes: 0
From: Columbus, Ohio
Year: 1997
Model: Cherokee
Engine: 4.0, comp cam, 99 intake, apn header, neon injectors, Thunderbolt 2.5" High Flow Cat
ok, the upgraded intake on the 99 is irrelevant unless it's on an older model. The reason for the intake is because in 99 chrysler made changes to the exhaust and computer as well as a few other things to reduce emissions, that also reduced the power output by 15 horse. so they upgraded the intake to try to regain some of that power. so a 99 with a 99 intake = stock jeep without the option for an intake upgrade.
Most 99's do not have the 0331 head so that isn't usually a problem.
in 98 for some god unknown reason chrysler decided to use all the same sensors but change the plugs on all of them so the older ones won't fit, and they can charge you 2 to 4 times as much. Other than that, they're good though. Not much downfall to them.
Most 99's do not have the 0331 head so that isn't usually a problem.
in 98 for some god unknown reason chrysler decided to use all the same sensors but change the plugs on all of them so the older ones won't fit, and they can charge you 2 to 4 times as much. Other than that, they're good though. Not much downfall to them.
CF Veteran
Joined: Dec 2010
Posts: 1,700
Likes: 0
From: S.Jersey
Year: 1999
Model: Cherokee
Engine: 4.0
I love my 99. It was built in june. Should I check the head to make sure?
My buddy has a 2k. I told hime he is ridding around in a granade...lol but so far so good.
My buddy has a 2k. I told hime he is ridding around in a granade...lol but so far so good.
Trending Topics
CF Veteran
Joined: Jun 2009
Posts: 2,173
Likes: 0
From: Columbus, Ohio
Year: 1997
Model: Cherokee
Engine: 4.0, comp cam, 99 intake, apn header, neon injectors, Thunderbolt 2.5" High Flow Cat
Junior Member
Joined: Sep 2010
Posts: 93
Likes: 0
From: Duluth, Minnesnowta
Year: 2000
Model: Cherokee
Engine: 4.0L
Or just buy it and drive it until it fails. Its not guaranteed to fail if its the 0331. But if it does like my '00 did (at 195k!), you can make a frankenstein engine. I have a stock '00 block and intake with an 0630 head from a '99 and running coils. The only thing that I ran into is that nobody seems to stock the right upper heater hose. I guess placement changed slightly..?
I'm running an early '99.
it had 254xxx miles on the original motor, trans, tcase, and clutch. minimal rust (for the salt belt), and the only thing wrong with it was the motor had a bad wrist pin.
I put a '95 mopar remanufactured block with .030 pistons in it with a '95 head, the '99 intake, borla, bored TB, srt4 injectors, etc.
it rips. the old motor is being bored and rebuilt as a stroker. and it had an 0630 head casting, not 0331. I'm still putting the spare '95 head that I have on it, as the exhaust ports are bigger, and it has a higher nickel content in the casting.
so, long way around, it's perfectly fine. I wouldn't want the distributorless setup...too much PITA to deal with.
it had 254xxx miles on the original motor, trans, tcase, and clutch. minimal rust (for the salt belt), and the only thing wrong with it was the motor had a bad wrist pin.
I put a '95 mopar remanufactured block with .030 pistons in it with a '95 head, the '99 intake, borla, bored TB, srt4 injectors, etc.
it rips. the old motor is being bored and rebuilt as a stroker. and it had an 0630 head casting, not 0331. I'm still putting the spare '95 head that I have on it, as the exhaust ports are bigger, and it has a higher nickel content in the casting.
so, long way around, it's perfectly fine. I wouldn't want the distributorless setup...too much PITA to deal with.


