Need help bad with XJ overheating problem...out of ideas!!

[VanIsle_Greg]

Also. When I pulled the head the # 3 and 4 head bolts on drivers side had rust in holes and on bolts. These bolt holes are blind but they obviously had coolant on them.. Gasket leaking?

Hmm... sounds like it. Man, you tried that fan setup and no go eh, how do you like it overall, thought about buying one? Definitely a bigger issue than anything simple. I bet the head swap will solve the issue... must have been a bad gasket.

 

[expeditionxj]

Hmm... sounds like it. Man, you tried that fan setup and no go eh, how do you like it overall, thought about buying one? Definitely a bigger issue than anything simple. I bet the head swap will solve the issue... must have been a bad gasket.

I tried the dirtbound Efans and liked the setup overall , not sure if the cfm claims are that accurate and in the end didn't change the temps I was running so I put the stock efan and mechanical with ZJ clutch back in and sold the dirtbound fans.

 

[chasdb]

The only other things that I have heard of are an exhaust leak directly on to the block, floss was tied to a stick and moved between block and header where a crack was found, that was on a HO. I know on the 2000 the manifolds are cast and connect via the precats so this may be a non issue.

Timing on the 00 are set by removing the cam position sensor off the oil pump drive shaft, rotate crank to TDC, verify compression on cyl 1 and 0 deg on vibration damper. A tooth pick should slide into a hole from the oil pump drive to the pulse ring. If it dose not align pull the pump drive, insert tooth pick and rotate drive to mate with slot in oil pump. The CMP will face the the rear of engine at 0 deg. I haven't had to do this on my rig yet. I have heard when set this way you may not need to go to the dealer/ some one with a DRB scanner and verify SYNC is in range.

I'm headed to Hanna Flats for the weekend with the family, wish you luck with your project.

 

[expeditionxj]

I'm headed to Hanna Flats for the weekend with the family, wish you luck with your project.

Bring some rain gear with you, we have been getting some MAJOR thunderstorms up here the past couple days. Pouring right now...

 

[haminawag]

back to basics

Spark plugs? Cat. converters? Hood clearance? Geez buddy, you've heard enough BS to last you a lifetime!! Go back to basics already, Pull the friggin' head. Check its casting number. Check the block number. Be sure they match. Don't go to PEP Boys for this!! Go to MoPar. If it's the right head then have it decked and pressure checked to be sure it's FLAT and all water orifices are clear. Then check the block deck for flatness and pray it isn't warped. Then clean all of the water orifices in the block with a length of 1/8"welding rod. Then get the CORRECT head gasket and put it back together. Before refilling the system reverse flush the cooling system, THEN add a 50/50 mixture of new antifreeze.

OR Just take the truck to a good radiator shop and have them reverse flush the cooling system, it isn't expensive and it might just do the trick. You mentioned one thing that no one seemed to have noticed, you said that some head bolts had rust on them. ANY rust in a cooling system is abnormal and can cause the very problem you've been having. I can't overstate how critically important it is to flush and refill your cooling system with NEW antifreeze (50/50) every year. I hope a simple reverse flush solves your troubles. Good luck. :ylsmoke:

 

[VanIsle_Greg]

Spark plugs? Cat. converters? Hood clearance? Geez buddy, you've heard enough BS to last you a lifetime!! Go back to basics already, Pull the friggin' head. Check its casting number. Check the block number. Be sure they match. Don't go to PEP Boys for this!! Go to MoPar. If it's the right head then have it decked and pressure checked to be sure it's FLAT and all water orifices are clear. Then check the block deck for flatness and pray it isn't warped. Then clean all of the water orifices in the block with a length of 1/8"welding rod. Then get the CORRECT head gasket and put it back together. Before refilling the system reverse flush the cooling system, THEN add a 50/50 mixture of new antifreeze.

OR Just take the truck to a good radiator shop and have them reverse flush the cooling system, it isn't expensive and it might just do the trick. You mentioned one thing that no one seemed to have noticed, you said that some head bolts had rust on them. ANY rust in a cooling system is abnormal and can cause the very problem you've been having. I can't overstate how critically important it is to flush and refill your cooling system with NEW antifreeze (50/50) every year. I hope a simple reverse flush solves your troubles. Good luck. :ylsmoke:

XJ's are notorious for running HOT when operating at low speeds under load, there is a lot of engine in a very small space. If your engine has issues any one major or a combination of smaller ones, this can cause or add to overheating problems. I agree this is probably either a warped head, a bad gasket or a clogged cooling system, but it sounds like those were already addressed to no avail. He did state that he had the head replaced with a re-manufactured one right in the beginning, along with most of the cooling system. So if you have already done the basics and some major stuff and it didn't help solve the issue, maybe your issue is a combination of smaller things?

I do agree that the rust on the studs is odd...

I still think a coolant passage is blocked, that reverse flush could help, although I had one done years ago and my head gasket let go 2 days later...was probably close to the edge already.

 

[Mistah Mike]

I just read through all this and I never saw it mentioned so I'll throw in my .02 It may be obvious, but when you changed the radiator, fans etc, did the mechanical fan's plastic shroud get reinstalled?

 

[expeditionxj]

Update. Got the new Clearwater head installed Friday and put it through its paces today. Performed great, climbed to 225 once while on a rocky climb in 4lo at about 5 mph, went back down once I turned the A/C off. This was at about 90 degrees. Other than that, around town with no a/c was 198 - 205 and with a/c in traffic climbed to about 215. All seems pretty normal given the conditions and altitude I run at.

So whether it was the head or gasket, who knows. But given the history of the 0331 heads I would guess the head has a small crack allowing combustion gas into the cooling system.

So hopefully this thread helps someone else. Will keep this updated in the future.

Thanks to everyone for suggestions,

Daniel

 

[expeditionxj]

Throughout this ordeal I've often wondered what percentage of cfm the fans lose when operating at 7, 000 feet. With the thinner air they can't pull as much through the radiator, anyone have any idea of the actual loss in efficiency?

Thanks

 

[VanIsle_Greg]

Glad to hear it is back and working as expected... nice feeling.

 

[Morticon]

Glad you got your issue fixed!

I don't have a problem as long as I keep mine Running... Haha if I run into a store real quick and come back out its pretty rough starting and the temp is up but as soon as I give it some gas the temp comes back down and everything is fine. Anybody have any suggestions?

 

[editedforsafety]

There was a tech bulletin about heat soak on injector number 3 causing rough starts/idle after being shut down and restarted shortly after in hot ambient temperatures. Basically, the heat would cause the fuel in the injector to vaporize, leading to vapor lock. Their fix was a heat shield for the injector. Not sure about the temperature being up though.

 

[jeep-N-montero]

Throughout this ordeal I've often wondered what percentage of cfm the fans lose when operating at 7, 000 feet. With the thinner air they can't pull as much through the radiator, anyone have any idea of the actual loss in efficiency?

Thanks

I have driven my Jeep over passes with elevations just over 13,000 feet when I lived in Colorado and it ran just fine. The fan itself doesn't lose cfm as it is turning at the same rate as it would at sea level at a given engine rpm, it is the air that loses its density and becomes less efficient at cooling. But typically the higher the elevation becomes, the air also becomes cooler that passes through the radiator.