Possible Cracked Head

K_Dom

K_Dom

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Original poster
Joined
Aug 13, 2021
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62
Location
Springtown, TX
New member here. I have a 2000 4.0. My issues first started with a cracked radiator. I replaced the radiator, cap, overflow bottle and flushed the coolant system. Started having some slight overheat issues. I then replaced the thermostat. Things were better but had a leak in the upper hose. Replaced the hose. After all this, I was having issues with overheating and low coolant. Replaced the radiator cap once again and the fan clutch and now I no longer have the overheat issue. Now though I have a mysterious coolant loss. I do have a 0331 head. I looked inside of the head and it looks like there could be a slight bit of milky residue. The oil itself looks good visually and the amount of oil is not increasing. So long story short, I think my head is cracked. I'm looking at my options of replacing the head myself or taking it to a local shop. If I take it to a local shop, what would be a reasonable cost for a head replacement. I'm sure prices will vary but just trying to get a ballpark figure. Thanks.
 
:ROFLMAO: I went into this thread thinking it was going to be a photo of a Possible Crackhead. not a Cracked Head...

Any blue smoke, coolant bubbling in the overflow, excessive bubbling with the rad cap off? I'd be a bit worried that the overheating may have caused something to warp.
 
No smoke or coolant bubbling in the overflow. Haven't checked for excessive bubbling with the cap off. The overheating was never real extreme, As soon as I would see the temp start to rise, I pulled over to let it cool. But I have only had the jeep 7 months. I don't know what the previous owner did to it.
 
Turn the engine off when it's hot and wait a few minutes. Look down the oil filler cap, and you should be able to see coolant bubbling into the head, if cracked.
 
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If @bromel's trick doesn't work I'd clean the engine really well with a degreaser and add some UV dye to the system. It may help you pinpoint where the loss of coolant is.
 
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bromel said:
Turn the engine off when it's hot and wait a few minutes. Look down the oil filler cap, and you should be able to see coolant bubbling into the head, if cracked.
Click to expand...
Since the head is a 0331 and a year 2000, I bet that this will work !
( Ask me how I know ;) ). My XJ didn't have any other signs , e.g. milky oil , overheating , bubbling coolant eta.
But at times it would miss fire for about 2-3 seconds after a hot restart after setting for 5-10 minutes.
I hope this all works out for K Dom !
Also look at the underside of the oil fill cap , any moisture / light film is not condensation.
 
Well this evening I got it up to temp and then looked in the oil filler cap. Couldn’t see any bubbling but with a better flashlight I was able to see a crack. So head replacement it is. So once again If I take it to a local shop, what would be a reasonable cost for a head replacement. I'm sure prices will vary but just trying to get a ballpark figure
 
Clearwater and rock auto for your parts.

pits not really that bad, I know it’s an xj…. But same engine. Did that two weeks ago

61687FE8-1AA0-4314-AE69-3DE23F16F3A6.jpeg
 
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