Hey crew. I unfortunately have been blessed with the **** 0331 head on my 2000 xj and its starting to run hot. I've gotten some great info and input from some guys here already, but figured I'd also open it up to everyone and hope it can help someone else as well.

I just picked up a 180 thermostat and some DEI header wrap and plan to flush everything out and clean the radiator, but wondered if I should take other measures.

Should I pick up a new head (Clearwater seems to be a good choice) just to be preventative before my stock does the inevitable crack?

Perhaps upgread the water pump (although this seems to only help at low rpm and idle)?

What about picking up a Banks header to help with the heat?

Any help or advice is appreciated and thx again to storm and j91gt83b for their above suggestions.

I would start with what you stated. Flush the ENTIRE system and change the themostat. i have a feeling that will solve your problems. I have a 2000 as well and only have an issue of running hot when im sitting in traffic, not when normal driving.


When you say running hot, exactly how hot is it getting?

Flushing the system is a good start. Before you get there I would get the engine hot and make sure all the hose are hot (getting coolant flow).

Thx.. sometimes in stop-and-go it gets up to 230 and on long idle it has maxed out before. Normal driving it usually sits at 200/210.

Great. Will do. Thx.

In the XJ manual it says that something in long traffic waits you would have to drop it into neutral and rev it up to push more water thru the radiator. Just an idea.

I would also look in to the fan clutch as well.

Right on. I believe I read that as well. What exactly is its function?

Thanks for the tip.

It basically keeps your fan moving at slower engine speeds like when sitting in traffic, idling or wheeling and then at higher speeds makes the fan spin freely so the engine doesnt waste energy spinning it.

Much thx to all for their suggestions and input. Thx to wb joe, we swapped out the clutch fan and dropped in a 180 thermostat. After a fluid flush, she idled and ran in stop and go traffic while in 80 degree heat without going above 210. Looks like problem solved. Thx again for the support CF.

Not to ruin your success, but won't dropping in a lower t-stat make your gas mileage go in the dump?

flush the system and new thermostat...

then run water and glycerin mix(make sure to change it out for the winter)

Considering the MPG is already terrible to begin with, ill take a few less miles over running hot or cracking the head. Just saying.

Could you do me a favor and post up how bad your mpg loss was from changing to the 180. I'm curious.

Ok, after a few fill-ups now (sorry I don't really drive much living in NYC) I can say its really not that noticeable. Maybe took it from 14mpg to 13/12mpg.... honest, at that point it really doesn't matter. If MPG is something of consideration for you when upgrading your truck.... don't own an XJ. Ill take a loss in MPG over running hot and potentially cracking a head. Happy wheeling and good luck.