Hey folks,

I'm new here and have an issue with a 2000 4.0 Cherokee Classic. It's my daughters Jeep.

2000 Classic
4.0
250k Miles
Auto / AC

And I don't know much about Jeeps.

Note: The Jeep was running smooth as a clock prior to radiator failure.

The plastic radiator side split and dumped all antifreeze. I believe she drove about 10 miles after it happened. She said temp gauge never went past the 220 mark. (it usually runs right @ 210 */- a degree or two) But I'm not sure if I trust the gauge, so I'm picking up a sensor today.

She pulled off and parked it. It sat overnight. When I got there I added water and it poured out the side. I needed to drive it about three 3 miles
to a safe spot off the road.

When I fired it up it was missing on one cylinder. Got to safe place, replaced radiator and thermostat @195 just cause I was there. Added 1 gal a/freeze on cold block. Then started the Jeep to add more a/freeze. Within several minutes, maybe 3 minutes, the fluid started gurgling back out the top at the radiator cap. And still missing. After all that, I needed to get the Jeep home, so I drove it 30 miles. It stayed right at the 210 mark, never went over and of course, still missing.

I'm thinking it popped a head gasket. At the house, I checked plugs and they are all dry and clean. Replaced the coil rail because I had one and thought maybe it might have gone icky-puck if it got too hot.

So anyway ,.,,, if anyone has a thought on this ... I'm concerned where that miss is coming from and if maybe a head gasket is causing it.

Appreciate your help!

Chap
Kentucky

 

Those years are known to have head cracking issues.

If it overheated chances are it cracked the head.

 

Engine light on? I'd check for codes to see which one is missing and then compression check that hole.

 

Check to oil and see if it has any coolant in it if so she's going to need a new head. You may want to also want to do a compression test to verify. Like mentioned above more then likely she did crack the head from driving so far after it over heated.
BTW, Welcome to the forum.

 

Compression test will likely show a loss of compression in cylinders 3 & 4 due to a crack in the 0331 head that is on her XJ.

A replacement head will be needed.

 

Thanks guys for all the responses.

Pulled the v/cover and the head was so full of sludge, I've been scraping and vacuuming with the shop vac this afternoon. Got most of it out and I'm just about thinking to throw the pressure sprayer on it. Don't reckon it would hurt anything. Just make a mess elsewhere.

Anyway, I don't see any obvious cracks, so I'm asking where the most likely place a crack might occur on that 331 head. I understand between the 3 & 4 cyl but where? On the rocker pedestal?

Also heading down the road to pick up a compression tester.

And no engine light and no codes....

Chap

 

Compression Test ...

Front to Back

1) 160
2) 50
3) 125
4) 150
5) 160
6) 150

Well, there it is. Reckon, that's a head pull.

Chap

 

Odd spot for that head to crack. Looks like you might be lucky and only have a blown gasket.

Get the head magnafluxed and machined anyway. No reason not to while you already have it off.

 

xjsnake,

A gasket is my optimistic hope. I agree, a magnaflux and machining never hurt anyone.

Chap

 

My 2000 XJ had #6 at 30 PSI it was a burnt exhaust valve of all things. Head is still in great shape but I replaced it anyway. With my luck why tempt fate.

 

If you have access to air.
Get it to TDC on #2 and and pressurize it with air to see where the compression is going before ripping the head off.
Reason I say is cause I'd hate to see you spend the money on the head and after all the work.. Uh oh... Bottom end..

 

JeepingDan ...

Hmmm. Yes, have 150psi compressor on hand. Gosh, that hurts just thinking about it.

Chap

 

Heading out to see if I can yank this head today. Gonna be a long hot day.

 

Best of luck to you!

 

Good Luck!