Ok, my 2000 XJ's cooling system doesn't seem to be working at 100%, I would appreciate some help tracking down the issue, because I'm stumped. Here goes:

-About a month ago, overheated on long hill in 100F ambient temps, no steam/boiling over but check gauges light came on, and the gauge did the jump to red.
-talked to my mechanic, found out my fan clutch/rad cap were bad, both have been replaced, fan clutch with the HD ZJ one.
-As of now, still likes to heat up at idle, no matter the ambient temp, but it never over heats, just creeps up, sometimes trips the e-fan, but this is usually at a normal stop light... Like, in 3 minutes.
- while driving, it fluctuates quite a bit between a needle width below 210 and a needle width above, sometimes more.
-HERE is the main problem: on any decent hill, highway or not, the temp will start to creep up, PAST the aux fan point like it's beginning to overheat.
- also coolant flushed 3k miles ago, it's a little murky but not bad.
- I inspected the head when I did the valve cover gasket, I couldn't see a crack (it's a 2000 so I wanted to make sure)
-Idk if this is relevant, but at 2800 rpm there is a weird whine/squeal... Belt tension?
- I have no idea if the rad/water pump/thermostat has ever been replaced...
-finally, after driving it for 2 hours or more, the temps suddenly don't want to come down as easily. This improved a little bit with the new fan clutch...

SO basically I searched the forum and couldn't find anything like this... Heating up under load and at idle but not when driving... Ideas?

 

"I have no idea if the rad/water pump/thermostat has ever been replaced"

I'd start there.

 

So, basically heating up under pretty much every driving condition.
Agree with djb, new radiator/thermostat/wp is next.
while you do this, might do the hoses as well and have everything done on the cooling system overhaul list.

Cooling system maintenance is very important, especially in your 0331 head '00

 

Not really weird at all, considering the fact that only 1 of the 4 main cooling system components have been replaced.

The real "weird cooling issues" threads r the ones where the OP has replaced everything in the cooling system and the darn thing still overheats. Those r the real stumper/head scratcher threads.

I would think 99 times out of 100 if all cooling system components were replaced at the 1st sign of running hotter than usual......an overheating thread would end up NOT even being post.

 

That would be so sad.

 

Well then, looks like I have my work cut out for me. I've read through a few threads, my guess is that if I'm going to do this, I should do all of it at once? So a new thermostat, new rad, new water pump, new hoses, and coolant? Also is this doable for an inexperienced 17 yo? I'm sure I can find out how to do it, just wondering if there are any problem areas I should know about.

 

One of the easier jobs and pretty cheap too. I'd maybe flush it a few times with full distilled water fills to clear out the engine block before you replace everything. Don't use tap water, and don't let it get near freezing.

 

Alright sounds good, time to order some parts...

 

It is good to do this at once, for the simple reason you will only have to drain and refill your coolant once.

It is do-able, also for the inexperienced. In fact, my first automotive maintenance job was the waterpump on the XJ. Basic tools, two hands and the Factory Service Manual and patience. Take your time.

If you don't have one, it's recommended you get a FSM for any maintenance you'd like to do. Background info, testing methods, removal and installation step-by-step etc etc. Worthwhile looking into getting one.

Read up on the procedures, get your parts, and post any questions you have.
You'll be fine mate, this is how we all began once this is done, you'll feel pretty great.

Let us know how you go.

 

Get your phone out and take pics of what things looked like before they were removed. Remove the old rad 1st and install the new rad last. New water pump , t-stat and fan clutch will install so much easier with the rad out of the way.

When both the stat cover and old water pump r removed, stick a garden hose in the stat hole and flush crud in the head/block out the pump hole. Flush the heater core with the garden hose as well.