New to Jeeps, lots of questions

[vr4operator]

Hello! While I'm not new to vehicles, the '99 Cherokee is new to me. Shes bone stock, 126k miles.

It doesn't appear that the prior owner kept up with maintenance. Oil is dirty, air filter is real dirty and rusted. Oddly enough, the tranny fluid looked and smelled newer. I know my way around a vehicle, I also know some vehicles are very picky about plugs and fluids, etc.

Looking for what people are using and what doesn't work. I'm a believer in Wix filters in my high performance car and plan on the same here. I also plan on using a synthetic oil in the engine and drivetrain. I heard the best plugs to use are Champion Coppers.

It still has the stock air box. Any suggestions? I've used K&N in the past and was happy with mileage/performance. But I know they aren't worth the money in all vehicles. I'm not proud, if a piece of pvc covered with a coffee filter is the best, then Mr Coffee and Home Depot get a visit tomorrow ;)

Also, I've read '87-99.5 are real good. '99.5+ have a better intake manifold. I looked at the door frame and while shes a '99 model year, she was built 3/98, so I'm guessing shes on the 99 side vice the 99.5?

Thanks in advance for any and all advice. For now, its just gonna be a daily commuter, but here in New England, my daughter def needs the 4x4 in the snow (which by the way, shifted into gear nicely)

Take Care,

Butch

[Mudderoy]

Hello! While I'm not new to vehicles, the '99 Cherokee is new to me. Shes bone stock, 126k miles.

It doesn't appear that the prior owner kept up with maintenance. Oil is dirty, air filter is real dirty and rusted. Oddly enough, the tranny fluid looked and smelled newer. I know my way around a vehicle, I also know some vehicles are very picky about plugs and fluids, etc.

Looking for what people are using and what doesn't work. I'm a believer in Wix filters in my high performance car and plan on the same here. I also plan on using a synthetic oil in the engine and drivetrain. I heard the best plugs to use are Champion Coppers.

It still has the stock air box. Any suggestions? I've used K&N in the past and was happy with mileage/performance. But I know they aren't worth the money in all vehicles. I'm not proud, if a piece of pvc covered with a coffee filter is the best, then Mr Coffee and Home Depot get a visit tomorrow ;)

Also, I've read '87-99.5 are real good. '99.5+ have a better intake manifold. I looked at the door frame and while shes a '99 model year, she was built 3/98, so I'm guessing shes on the 99 side vice the 99.5?

Thanks in advance for any and all advice. For now, its just gonna be a daily commuter, but here in New England, my daughter def needs the 4x4 in the snow (which by the way, shifted into gear nicely)

Take Care,

Butch

Hey welcome to the site. Many consider the 1999 the best XJ year made!

First thing I would do is change fluids. Along with that at least the lower radiator hose. They will burst after they are old.

Things you may need to change would be wheel bearing assemblies and perhaps front end parts like tie rods. Especially if they didn't grease them.

That rusty air box may actually be rusty coolant from the radiator. You might want to take the garden hose and rise that radiator out with that lower hose off.

Then fill it up, run it a few minutes, drop the lower hose, etc...

That rusty water gets pretty thick and will cause cooling problems in the radiator.

[cantab27]

dang tony , thats a mighty fine answer right there..welcome butch and yeah what tony said x2

[4.3LXJ]

Welcome to the forum Butch. As far as March manufacture date, I think you are right on the border there. Model year starts in Oct of the previous year. Most guys use 10W40. But I have always used higher viscosity oils. One thing you have to watch on the 4.0 is that it has flat tappets. Most of the new oils, especially synthetic don' have the additives for flat tappet engines. Of all the brands, Valvoline is the best I think. Their synthetic has the proper additives for what you need. But better have them talk to the factory rep to be sure. I know for a fact that their paraffin based racing oil has the highest amount of additives for flat tappet engines of any oil on the market.

[Brasscatz]

Welcome to the forum Butch. As far as March manufacture date, I think you are right on the border there. Model year starts in Oct of the previous year. Most guys use 10W40. But I have always used higher viscosity oils. One thing you have to watch on the 4.0 is that it has flat tappets. Most of the new oils, especially synthetic don' have the additives for flat tappet engines. Of all the brands, Valvoline is the best I think. Their synthetic has the proper additives for what you need. But better have them talk to the factory rep to be sure. I know for a fact that their paraffin based racing oil has the highest amount of additives for flat tappet engines of any oil on the market.

Great info Steve. I was contemplating Royal Purple since I used that in ny old truck. You saved me some money

[Cheromaniac]

Hello! While I'm not new to vehicles, the '99 Cherokee is new to me. Shes bone stock, 126k miles.

It doesn't appear that the prior owner kept up with maintenance. Oil is dirty, air filter is real dirty and rusted. Oddly enough, the tranny fluid looked and smelled newer. I know my way around a vehicle, I also know some vehicles are very picky about plugs and fluids, etc.

Looking for what people are using and what doesn't work. I'm a believer in Wix filters in my high performance car and plan on the same here. I also plan on using a synthetic oil in the engine and drivetrain. I heard the best plugs to use are Champion Coppers.

It still has the stock air box. Any suggestions? I've used K&N in the past and was happy with mileage/performance. But I know they aren't worth the money in all vehicles. I'm not proud, if a piece of pvc covered with a coffee filter is the best, then Mr Coffee and Home Depot get a visit tomorrow ;)

Also, I've read '87-99.5 are real good. '99.5+ have a better intake manifold. I looked at the door frame and while shes a '99 model year, she was built 3/98, so I'm guessing shes on the 99 side vice the 99.5?

Thanks in advance for any and all advice. For now, its just gonna be a daily commuter, but here in New England, my daughter def needs the 4x4 in the snow (which by the way, shifted into gear nicely)

Take Care,

Butch

Welcome to the forum Butch.
You probably do indeed have one of the best 4.0L engines ('96-'99.5) that came in the XJ. The later '99.5-'01 engines with the curved runner intake manifold and coil-on-plug ignition system have the crack-prone #0331 heads and the '87-'96 engines, though bulletproof, don't have the NVH fixes (including the main bearing cap girdle).
The curved runner intake manifold from the later models is desirable for the small performance and mpg gains you'd get from it so it's a worthwhile swap if you can find one cheap.
Like Tony said, I'd change both the upper and lower radiator hoses and I'd also change the smaller heater hoses for good measure. I'd also replace the thermostat (use stock 195*) and while the thermostat housing and lower radiator hose are off, you can flush the cooling passages inside the engine with a garden hose as well as flushing the radiator.
Spark plugs? Use the stock Champion copper core plugs. None are better-performing and though platinum plugs will last longer, they're not really worth the money.
Engine oil? DON'T use synthetic if the engine's been used to dinosaur juice all of its life. Synthetics tend to contain less of the ZDDP that's required to protect flat tappet cams/lifters, and synthetics also contain more detergents that'll strip away the gum/varnish from old oil seals causing leaks (rear main crank seal being the biggest PITA). Just use a good quality SL-rated dino oil (10W-40 will be fine, use 15W-50 if oil pressure is less than 15psi at hot idle).
Definitely check greasable items as Tony mentioned like tie rod ends, ball joints, and driveshaft universal joints for excessive free play as signs of advanced wear. Either replace as necessary or break out the grease gun.
I would definitely NOT swap a K&N FIPK in place of the stock airbox. It simply isn't worth the money and the heatsheild is useless. You could probably fab a better one yourself with a universal S&B cone filter and a few bits from Home Depot. Otherwise just put a K&N panel filter inside the stock airbox and be done with it.
You might also want to pull the rear brake drums and spray some brake cleaner onto the shoes and adjuster mechanisms to clear out all the caked on dust. Replace the shoes if worn and readjust the handbrake cable as required. Check the front brake pads as well and replace if necessary. Otherwise give those the same brake cleaner treatment.
Check the brake fluid in the master cylinder reservoir and if it looks dark and nasty, replace it with fresh fluid and bleed the system. Same also applies to the power steering fluid.

[TimmyTXJ]

Hey welcome to the site. Many consider the 1999 the best XJ year made!

First thing I would do is change fluids. Along with that at least the lower radiator hose. They will burst after they are old.

Things you may need to change would be wheel bearing assemblies and perhaps front end parts like tie rods. Especially if they didn't grease them.

That rusty air box may actually be rusty coolant from the radiator. You might want to take the garden hose and rise that radiator out with that lower hose off.

Then fill it up, run it a few minutes, drop the lower hose, etc...

That rusty water gets pretty thick and will cause cooling problems in the radiator.

That's the second time in as many days that I've read about the lower radiator hoses being a weak spot if they're old. I'm gonna change mine out this weekend! :D

Butch welcome to the site, super nice and knowledgeable people here. I'd also suggest that you change out the inline fuel filter near the gas tank. That will go a long way to keep junk out of your engine and it's something that's often overlooked (I don't think mine had ever been changed). It's not a glamorous upgrade, but it sure goes a long way to getting the "fuel" part of optimum air-fuel ratio in line.

Remember that the fuel line is always under pressure so make sure to open the gas cap and bleed pressure from the system at the test port on the fuel rail before disconnecting anything.

[vr4operator]

Wow.

Thank you all for the fast, great and informative responses!

As 4.3LXJ said, March is on the borderline of manufacturing. With a date of 3/98, is there a way to ensure which side of the timeline I'm on? Maybe an obvious visual difference in the intake manifold?

Def will swap out the upper/lower rad hoses, was gonna flush it anyway. Will change out the T-stat too. I'll inspect the heater hoses. If I remember right, they look easy to swap out, being a car guy, some have been a major PITA.

Thanks for the intel on the fuel filter, I noticed it wasn't in the engine bay and wondered if it was in-line or in tank, so thats getting changed. Will grease all the zerks too.

Decided on sticking to dino oil. Didn't realize it was a tappet motor. My '71 Vette is the same.

While we are talking oil, recommendations for X-fer case, tranny and diff?

Thanks again,
Butch

[4.3LXJ]

My opinion is the best gear oil for a diff in synthetic is Amsoil, it is what comes in Atlas products. Also Red Line makes some good stuff. I use high heat synthetic in my auto tranny. But I rebuilt it so it was dry and easy to go that way.

[xj4life2]

As for you year question , at 3/98 we would consider it a 98 not a 99. When it come to basic maint. on an XJ the biggest factor in my opinion is keeping the cooling system 100% functional and in perfect operating condition. As for oil I don't like the parafin based oils but in the 4.0 they seem to do the best, being form the east coast I would say that the Kendal 10/40 is what I would use and stick with the Wix filters. If you have a NAPA store in the area the NAPA gold is made by Wix and somewhat cheaper. When it comes to Diff oil, I prefer a high pressure oil such as a synthetic. I dont sweat over name brands as they are made to specific standards and basically the same. Valvoline Syn. gear oil is my gear oil of choice.Trans and t/c use ATF if your an Auto. trans. again stick with the basics there but be concious of changes as far as intervals. I also use Power Punch in the T/C mine had almost 300k on it when I sold it and it still works to this day and makes no noise at all. I'm glad someone brought up the Champion plugs for the 4.0, not sure why but they love cheap plugs. Welcome and good luck with the new rig !!! Oh and if ya ever get to Situate , say hi to my uncle will ya !!

[vr4operator]

Again, ty all! I'm a HUGE fan of Wix. I literally buy them by the case for my twin turbo VR4, the Jeep will get the same love.

xj4life2, hes on the other end of the state, but if I'm over there, I'll def say hello!

And I trusted Valvoline gear oil in my '90 Pathfinder since '95 and it never let me down. Thanks!

[cpttuna]

A lot of xj owners run oversize filters.For example, the NAPA filter for your XJ is the Gold 1085. However, the NAPA Gold 1515 oversize filter will also fit. There are oversize filters from several other filter mfgs that also work. Also,if you are considering replacing your fan clutch, the NAPA 272310(from a 98 grand cherokee w/o max cooling) is a good choice. It is about twice as big,but still fits.

[vr4operator]

A lot of xj owners run oversize filters.For example, the NAPA filter for your XJ is the Gold 1085. However, the NAPA Gold 1515 oversize filter will also fit. There are oversize filters from several other filter mfgs that also work. Also,if you are considering replacing your fan clutch, the NAPA 272310(from a 98 grand cherokee w/o max cooling) is a good choice. It is about twice as big,but still fits.

Why the oversized filter? Other than more oil (which as it is, don't these beasts take like 6 quarts?). The oil filter neck size doesn't change, so the flow would stay the same, yes?

[Mudderoy]

Welcome to the forum Butch. As far as March manufacture date, I think you are right on the border there. Model year starts in Oct of the previous year. Most guys use 10W40. But I have always used higher viscosity oils. One thing you have to watch on the 4.0 is that it has flat tappets. Most of the new oils, especially synthetic don' have the additives for flat tappet engines. Of all the brands, Valvoline is the best I think. Their synthetic has the proper additives for what you need. But better have them talk to the factory rep to be sure. I know for a fact that their paraffin based racing oil has the highest amount of additives for flat tappet engines of any oil on the market.

Mobile One high mileage synthetic does.

[Mudderoy]

That's the second time in as many days that I've read about the lower radiator hoses being a weak spot if they're old. I'm gonna change mine out this weekend! :D

Butch welcome to the site, super nice and knowledgeable people here. I'd also suggest that you change out the inline fuel filter near the gas tank. That will go a long way to keep junk out of your engine and it's something that's often overlooked (I don't think mine had ever been changed). It's not a glamorous upgrade, but it sure goes a long way to getting the "fuel" part of optimum air-fuel ratio in line.

Remember that the fuel line is always under pressure so make sure to open the gas cap and bleed pressure from the system at the test port on the fuel rail before disconnecting anything.

I think it was me both times. ;)

[Carves]

Welcome aboard ...

X 2 on all the previous suggestions. New fluids and a grease is a good start.

Cooling systems can be a bit temperamental ... So a revamp of that is a worthwhile investment - as soon as you're able.

You might not find an external fuel fiter ... as the update 97+ models only have a little screen, under the fuel pump - inside the fuel tank ... to my knowledge.

Have fun with it ..

[vr4operator]

Got another question, when looking at things online, I'll get asked which model I have, a sport, a classic, a SE, Limited...

Whats the diff between a Sport and a Classic?

[4.3LXJ]

Level of trim and options. The basic mechanical stuff is the same

[vr4operator]

I read earlier about using a larger oil filter. Other than more area to filter, are there any gains to be made and has anyone had issues with pressure? I plan on using 10w40, prolly Valvoline VR-1

Also, I just paid $25 for a thermostat at the dealer! Holy crow! Is that normal? I mean, I know they are called 'stealerships' for a reason, but $25 for a t-stat? :out:

[bluedragon436]

I bought my T-stat from Autozone and paid like $10 for it, and another $2-3 for the gasket... I always price parts at Autozone or similar parts store, only things I pick up at the stealership is parts i can't get at auto parts shops..

[vr4operator]

I bought my T-stat from Autozone and paid like $10 for it, and another $2-3 for the gasket... I always price parts at Autozone or similar parts store, only things I pick up at the stealership is parts i can't get at auto parts shops..

Lesson learned on that one. I normally do buy them from the stores, but had read a few people swear by the Mopar made one. Thanks!

[vr4operator]

Another question on fluids, and I know this is usually a personal preference thing.

Diff, X-fer case, tranny fluids, what brand, what weight and how much? We live in New England, so colder winters, mild summers...

And just for clarification, if I'm not going synthetic on the engine oil, will the regular old dino Valvoline be tappet friendly?

And again, I can't say it again, you guys have been outstanding with your friendly help.

Thanks,
Butch

[4.3LXJ]

Valvoline dino oil is great stuff. Regular 90W or the equivalent is fine for the diffs. Tcase takes auto tranny fluid, just about any will be OK I think

[TimmyTXJ]

I think it was me both times. ;)

All the more reason to pay attention! :) Jim helped me get my cooling system all squared away this weekend. Replaced the upper and lower, switched out the thermostat and flushed the system with clean water.

[TimmyTXJ]

Welcome aboard ...

X 2 on all the previous suggestions. New fluids and a grease is a good start.

Cooling systems can be a bit temperamental ... So a revamp of that is a worthwhile investment - as soon as you're able.

You might not find an external fuel fiter ... as the update 97+ models only have a little screen, under the fuel pump - inside the fuel tank ... to my knowledge.

Have fun with it ..


Carves is right, fuel filter on 96 and older. Sorry about that Butch! :)

[vr4operator]

Carves is right, fuel filter on 96 and older. Sorry about that Butch! :)

Yeah, found out when I saw the filter, lol. Ugh. Oh well, unless there are fuel issues, it'll wait...


A new issue. While out buying fluids, the check engine light came on. I know for most vehicles, its usually something to do with emissions or gas cap. Have Auto Zone read it, PA455 (gas cap). The cap itself looks new, but if it doesn't go away, I'll buy another one. Whats $10 to get rid of a headache, right? Question is, how on these Cherokees do you reset them? I've had vehicles that you disconnect the battery, some that you gotta put the radio on this station, push this button, click here and hold yer nose while turning the ignition on and still others that only a scan tool could reset.

Thanks,
Butch

[Brasscatz]

disconnecting the battery should do it. But for future codes, you can check them yourself instead of having autozone do it. Here's a thread describing how to do that: http://www.xjtalk.com/showthread.php?t=11574

Also, you can buy a bluetooth adapter as shown here. I got mine for 15 bucks shipped: http://www.xjtalk.com/showthread.php?t=11044