Some 2001 Questions.

Just picked up a mint 2001 XJ with 99,000 miles on it. Paid $500 for it. Guy thought it had a blown headgasket but i disagree with him. Thing has been sitting for 3 years.

When i towed it home the other day i realized the serpentine belt was snapped. I think the belt just snapped and the water pump stopped circulating water and the guy thought something was seriously wrong and parked it. Whether or not he ran it for a while like that is beyond me. Even if it needs a replacement head i'm totally fine with that.

Anyways my questions so far are this;

It has a LP D30 in the front.

1) I have a HP D30 from my old XJ in my backyard. Can i just swap this in? I know they changed the headers and what not on this year and i think i read somewhere that the HP will hit on the exhaust or something like this if the jeep is at stock height. Is this true?

2) The brake lines popped the instant i touched the brake pedal. I'm going to run all new lines from the prop valve back. Should i just buy this (http://shop.advanceautoparts.com/we...-poly-armour_16190007-p?searchTerm=brake+line) and run that the entire way?

3) Never had to deal with the coil-pack ignition. When i do a tuneup instead of changing the cap (like on the pre-99) do i change anything to do with the coil pack? Or do i just change the spark plugs and plug wires?

Anything else i should do? Going to flush the coolant, change oil, etc etc. Just looking for ideas.

Alternator is also seized along with the A/C compressor and the battery is toasted. Jeep runs if i jump it though. Going to swap in a new alternator, one of my old Sanden compressors and put a new battery in and see if everything is fixed.

Here's a picture for kicks.

Is there something wrong with the LP D30 that's in it?
Unless you have an interest in lowering the gear ratio and off-roading it, I wouldn't bother, there is no advantage.

I use my 01' Off-Road with the OEM front and lower gears and don't hit anything with the pinion.

You could do that, you'll need fittings though, make sure you can double flare the stuff. Or you can buy straight lengths with ends on it that you couple together with unions.

Nothing fancy with coil packs as far as tune up. Check the plugs for gap and wear, and unless there is a reason to replace the wires (like they are cracked), I would leave them be. The plugs on unleaded vehicle last forever, and may just need to be re-gaped.

Check the PH or the coolant, and if it's good, leave it.

Change oil. I use a 10-30W NAPA/Valvoline. Use a good filter.

Alt will cost you

The AC is 134 on a 01', so you can charge your own arty:

Looks like a keeper

-Ron

Never trust a "previous owners" diagnosis.

The 0331 head on your vintage XJ cracks more often than the headgasket fails. Sure it could be the gasket. But you're going to need to do your own testing to find out.

Start with a simple compression test. A good snapshot in time of how things are doing internally. The compression spec. for the 4.0 engine is 120-150 psi with no more than a 30 psi variation between cylinders. The compression test is the recommended first test for checking for a blown head gasket, but know that the compression test will most often not be able to help you diagnose a cracked 0331 head. There is a factory defect between cylinders 3-4 on the 0331 head which all 00-01 XJs came with from the factory, which is where the 0331 almost always cracks if it's going to.

As for the head itself, start with removing the oil filler cap and with a good light, inspect carefully inside.....oftentimes you can visibly see the crack and see green antifreeze weeping through the crack on the 0331 if the head is compromised. Not seeing a crack though does not mean that you don't have one, but it only takes a few minutes so it's the first thing I usually do. A comprehensive cylinder leakdown test is best for diagnosis. Also perform a "block test" where you check the coolant for the presence of hydrocarbons.

And if you get it running as is, keep an eagle eye on the coolant reservoir as "unexplained coolant loss" is going to almost always be a symptom if you have a cracked 0331 head. I wouldn't put much money into the engine until you know what you've got. If the head is cracked and has been so for a long enough period of time, you will start to see low oil pressure which then would eventually necessitate an engine rebuild or engine swap.

Good luck and keep us updated!

birchlakeXJ said:

Never trust a "previous owners" diagnosis.

The 0331 head on your vintage XJ cracks more often than the headgasket fails. Sure it could be the gasket. But you're going to need to do your own testing to find out.

Start with a simple compression test. A good snapshot in time of how things are doing internally. The compression spec. for the 4.0 engine is 120-150 psi with no more than a 30 psi variation between cylinders. The compression test is the recommended first test for checking for a blown head gasket, but know that the compression test will most often not be able to help you diagnose a cracked 0331 head. There is a factory defect between cylinders 3-4 on the 0331 head which all 00-01 XJs came with from the factory, which is where the 0331 almost always cracks if it's going to.

As for the head itself, start with removing the oil filler cap and with a good light, inspect carefully inside.....oftentimes you can visibly see the crack and see green antifreeze weeping through the crack on the 0331 if the head is compromised. Not seeing a crack though does not mean that you don't have one, but it only takes a few minutes so it's the first thing I usually do. A comprehensive cylinder leakdown test is best for diagnosis. Also perform a "block test" where you check the coolant for the presence of hydrocarbons.

And if you get it running as is, keep an eagle eye on the coolant reservoir as "unexplained coolant loss" is going to almost always be a symptom if you have a cracked 0331 head. I wouldn't put much money into the engine until you know what you've got. If the head is cracked and has been so for a long enough period of time, you will start to see low oil pressure which then would eventually necessitate an engine rebuild or engine swap.

Good luck and keep us updated!

Click to expand...

Going through this right now, although I bought it knowing the head was cracked for around the same price. As long as you can determine the block is good, replacing the head seems like a great plan, as long as you don't throw another 0331 on there. I was able to really see the crack when I pulled the valve cover and there was just a huge buildup of sludge between the third and fourth cylinder.

Either way looks like a nice purchase, I got my '00 Classic in Silver for around the same price and same situation (Blown water pump lead to the cracked head even) and I'm plenty happy with it.

Alright update.

Oh, and by the way i bought this jeep knowing about the 0331 head issue. I actually bought it preparing to do a head job. Had to do a head jeep on my 99 XJ with a 0630 head. Just thought i might get lucky because when i first saw the jeep the serpentine belt was snapped so i thought maybe he just didn't realize the water pump wasn't spinning and that's all it needed.

On the flip side of that though i have no idea how much he ran it without a serpentine belt and that would annihilate that 0331 head in about 20 minutes. Haha.

I'll do a compression test tomorrow.

Anyways, i installed;

- New Alternator
- New A/C Compressor (Just the front part. Had a spare so i swapped it over. Old was seized.)
- New Serpentine Belt
- All New Brake Lines.

Fired it up and everything just began smoking. For the first 5 minutes the old brake fluid was burning off the exhaust manifold. That was expected. Tail pipe was also smoking (white smoke) as if someone poured some seafoam in the intake. Figured that was also normal because the jeep hadn't been ran in years. I also noticed that either the radiator is cracked or the upper radiator hose is leaking. After about 20 minutes of running the coolant flashed over and steam began pouring out of the upper radiator hose. I'm not sure if it overheated because the system couldn't keep pressure in the system to raise the boiling point or if the water pump is shot or what have you. The white smoke coming from the tailpipe never stopped.

Hottest the thermostat housing hit (checked with an IR gun) is about 275 degrees. (right after it flashed over. Hot, i know.)

Problems i've noticed so far with this jeep besides the obvious are;

- Temperature gauge on dash is broken.
- The shifter positions (P, R, N, D, 3, 2-1) don't light up when the lights are on.
- The fan only works on #4 speed. (Blower motor resistor if i remember correctly?)

Where would you guys go next? New radiator and hoses along with a water pump and see if it overheats again?

Compression test it first and then just eliminate the 0331 head all together?

I would do the minimum to check it out . After that new parts .

White smoke out the tailpipe is normally a good indicator of a blown H/G or cracked head. Did it push coolant out once warm? If started cold with the rad. cap off does the coolant bubble gurgle out of the filler neck?

westy2005 said:

White smoke out the tailpipe is normally a good indicator of a blown H/G or cracked head. Did it push coolant out once warm? If started cold with the rad. cap off does the coolant bubble gurgle out of the filler neck?

Click to expand...

Not sure on either. Didn't really pay it much attention. I'll tell you tomorrow. Anyways;

Compression. Throttle wide open and cranked until the gauge stopped rising. All spark plugs removed.

1 - 125 PSI
2 - 167 PSI
3 - 170 PSI
4 - 180 PSI
5 - 169 PSI
6 - 189 PSI

Any other ways to check for a cracked head/blown gasket?

There is the dye test for combustion gasses in the coolant. I think it's called a "Block Checker"

Basically a clear cylinder with indicator fluid in it which has a mesh funnel on the bottom holding the fluid in. You remove some coolant to make air space in the radiator, seat the funnel base of the cylinder in the radiator cap opening, then run the engine to warm then you draw air from the radiator thru the mesh and into the indicator fluid. If it changes color you have CO in the air = head gasket leak.

I got the kit from NAPA many years ago (and use it rarely) but it's a great checker.

I'm watching coolant levels on mine for now but if I were to have doubts I'd start with my block checker.

Low compression- not good.

(I have the same color '01

I too wouldn't swap out the lp 30 unless you where planning a bigger lift wheeling it or there is something wrong with it. I would do a plug change. Platinum plugs are a 100k service item.n Use platinum plugs in it too. The COP system use a waste spark design, and regular coppers will only last about 1/3 as long as the platinum.. I would have drained the oil right away and refilled it with some cheap dyno, and a cheap filter. Then changed it again to some good oil once you've got it running good. I would do a good coolant flush, and just use straight water until you determine if the head is cracked. All the other stuff is pretty much if it needs it....