WJ running hot but not overheating

[Synesthesia]

Hey all, thought I'd post this to a more WJ focused crowd. Right now I have a 2000 WJ, 4.7 QD with 142k on it. Lately since spring has rolled around it runs about 75% on the highway, and once goes past op temp won't really go below 60% or so until I come to a complete stop.

I'v had it for 6 years now and its not a daily driver though I do depend on it. Recently while towing a 2500lbs trailer and R1 it did hit redline so I instantly pulled over and let it cool. This is a trailer I'v pulled many times and even over great distance with no problem

I'v replaced the rad in another WJ and its not fun so is their anything else I should check before undertaking the project?

In the past 2 weeks I'v....
Replaced and flushed coolant (twice)
replaced thermostat (195 degree oe replacement)
transmission fluid changed (have drain plug)
oil (synthetic)
PS fluid changed

Thermostat seemed to make a slight difference for about a day. Both rad hoses get hot, and IF STOPPED, even if its 75% up I can let it idle and it will very slowly but surely return to 210. No leaks, cap pressure tests fine, electric and mechanical fan both seem to be working. If its 60 degrees outside its not so bad but once it goes over 80 it runs even hotter. Goes to 210 as it should then ever so slowly just creeps up and up to that 75% mark before stopping.

Anything I'v overlooked? I'll be doing it myself but its a royal pain. Waterpump and rad and factory original. I tow, I go wheeling, lots of road trips.

Thanks again.

[Forces]

Fan kicking in?

[volvite]

There are 4 possible things that I can think of with cooling.

1. T-stat failed open/closed. You said you already replaced that, so it's probably good to go.
2. Fan. Depends on what your WJ came with. There are so many different fan setups with WJs. I have a 99 with the 4.7L V8 and tow package. I have the clutch driven fan and an electric fan. Make sure both are working. Possible clutch going out on your mechanical fan. Possible bad relay on your electric fan.
3. Radiator. Cooling fins have been damaged, and therefore are not cooling as efficient as they should. Try, taking your hose and spraying water from inside the engine bay out to push the dirt/debris out. This may help. If not, possible radiator swap.
4. Water pump. I've seen threads that show the water pump blades actually falling apart and therefore not cooling correctly.

Those are about the only items beside the coolant needing replaced that I can think of. Good luck.

[volvite]

Don't mean to scare you but here is the link I was trying to think of when I was writing about the water pump. It's from this forum too.

http://www.nagca.com/forum/showthread.php?t=38876

[Synesthesia]

volvite - I saw that, and yes it does scare me, though wouldn't I be seeing some sort of coolant leak?

I also have an audi which are well known to have waterpump blades break off but haven't heard of it on a Jeep. Mechanical fan is working and working hard but can't see if electric fan is running with mechanical in place, just sounds like it (Yes, I have the factory tow package)

Haven't yet checked the relay but is that a common issue on the 4.7? I always seem to hear about it going bad on the 4.0?. Going to order waterpump and rad today but going that far in I want all bases covered. Suppose to drive from VA to Atlanta in mid june and simply don't trust it as is.

*Edit* The fins of the rad are fine, I do go wheeling but I clean it very often, including recently degreasing entire engine bay.

[volvite]

No it was all internal, and from what I read there was no external coolant leak. That's the scary part in that it did not show on the outside, so everything would look normal.

Cooling is such a tricky issue. I know my situation is both the water pump and t-stat have been swapped, but I still get hotter than normal temps. I'm actually deployed now, so the jeep does not get driven. The wife drives the pathfinder and will only drive the jeep once a month to keep fluids moving through it. However the only thing left for me to change will be the radiator, so that's on my list when I get home.

[Synesthesia]

So even with waterpump removed will there be a way to tell if cover is bad?

Been on various Jeep forums for 7 years and first iv heard of this issue. Past years it would run a hair below 210 during winter, a hair over in summer with a/c on. Year in year out, a bit hotter with heavy loads of 6-7k.

Found some used covers on ebay if needed but hoping to not go that route, so the question is - without taking off cover how to find damage

*edit* nevermind, took a closer look at pics and once waterpump is removed it should be clear.

Damn it, I started buying Jeeps for two reasons and two reasons alone.

1. Winter
2. Always works when audi breaks.

Everything else was just a bonus ;-)

[volvite]

From my understanding you should be able to see the hole if there is one. When I changed my cover, I didn't have the damage. I had to change the cover due to a bolt from the t-stat housing. My pump and cover were still in good shape except for that. When you buy a new cover from the dealer it comes with a water pump, so that's why I replaced mine. I would just do the pump and look to see if there is anything that looks like damage. If not you are probably good to go. I agree i've only ever seen this on the thread mentioned, but it got me all worried last year when I was having issues.

Just remember JEEP=Just Empty Every Pocket. However, I love my WJ. It was the best thing I could have bought when I did 4yrs ago. Only reason I would sell my 99 is to get an 04, just a few years newer. Need to find someone that needs one.

[Synesthesia]

Kind of interesting, in a "damn it" kind of way. Today it was just flat out hot, decided to take the Jeep and with the A/C on 55 and high all day long it was running hot above 210, but didn't once touch the 75% mark, barely the first hash past med.

Leads me to believe possibly the relay is going bad since turning on a/c should force it to stay on all the time.

I also removed front aux lights to increase some airflow. So either the rad is going bad and it needs the extra airflow to cool or relay going bad and I just wasted 180 bucks on rad+ WP

[volvite]

That sucks. How about your coolant? Usually summer time you can run more of a 60-70% water mix to help keep temps down. When you turned on the A/C did the fan kick on and stay on?