2000 xj classic coolant loss

Skullver · Aug 18, 2005

Anyone come across these symptoms? Coolant reservoir empties completely every 300 or so miles. I pressure tested cooling system, no leaks. headgasket is good. Oil has no signs of moisture. Im stumped, hopefully not micro-crack in block or something!

RichP · Aug 18, 2005

Two thoughts come to mind, leakey line from rad neck to overflow bottle or cracked bottle that only leaks when it gets hot coolant.
Bad water pump that leaks out the weep hole in the nose of pump. The seal in the pump will hold pressure during a pressure test but will allow coolant to seep thru while it's running under pressure.

TacticalFats · Aug 18, 2005

Mine did this too.

I eventually rebuilt the entire cooling system, part as overzealous preventive maintenence, part out of OCD, part because it needed it.

I found that it really needed hoses, I think there was a tiny leak in the radiator, it leaked around the hoses and the water pump was weeping.

All of these leaks were tiny, and you would only find a few tiny droplets which had been sprayed around by the fan. Sure did stink, though. Can you smell coolant ?

97 XJ, 89k

Dr. Dyno · Aug 18, 2005

I hate to say this but the 2000 4.0 models are notorious for getting cracked heads and yours could be one of them. The crack usually occurs on the topside between the no.3 and 4 exhaust ports so you might be able to see it by peering under the valve cover through the oil filler hole. If you can't see anything, you might need to remove the valve cover altogether to get a better look.

Skullver · Aug 18, 2005

I did at times, when fluid level was toward bottom, I checked it hot, cold and warm and never saw leakage. thanks for suggestions, back to checking hoses......again.

explorer · Aug 19, 2005

Dr. Dyno said:
I hate to say this but the 2000 4.0 models are notorious for getting cracked heads and yours could be one of them. The crack usually occurs on the topside between the no.3 and 4 exhaust ports so you might be able to see it by peering under the valve cover through the oil filler hole. If you can't see anything, you might need to remove the valve cover altogether to get a better look.

If this is a phantom coolant leak, this is where to look. Typically you will see the white/green crusty residue under the oil fill cap toward the back side.

Skullver · Aug 20, 2005

Thanks, I had this sinking feeling it was gonna be something like this as all hoses look goodntight. Thnks for replies all!

KaHOnas · Aug 24, 2005

Whatever came of this? I'm pretty sure mine's one with the head crack and I'm kinda wondering what you found out.

'00 4.0l sport 4wd auto

langer1 · Aug 24, 2005

It's also classic pressure cap bad.

2000 xj classic coolant loss

Skullver

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