wgyouree

Just bought my first XJ today, always have loved them and now I've got one It's a 1999 Classic 4dr 4x4, I6 auto with 137,000 miles, 4.5" lift and 33" tires.

Driving it back to Atlanta from Chattanooga, it made it about 40 miles on the interstate doing 75 with the AC on full blast before the temp gauge shot up to 250 and so I pulled over quick to let it cool down. Drove the last 100 miles at lower RPMs going about 60 and with the AC off, and the temp didn't get up past 220. (Could've been running around 212, can't tell b/c the gauge isn't very precise).

I suspect it could be either a bad thermostat or a clogged radiator. I'd like to replace the thermostat, water pump, fan clutch and the belt at the same time, and maybe just upgrade to a 3 row radiator and install a trans cooler at the same time, like is done here: http://jeephorizons.com/tech/xj_cooling.html

Does this sound right? Anyone recommend the above for my situation or think I should be doing something else? I've read a bunch of the posts and this seemed like a pretty comprehensive approach. Also, anyone recommend a good radiator and trans cooler? Does the "hi-flow" thermostat help at all?

warthog

how fast did it shoot up and did it cool down at abou the same speed.

reason i am asking is that if your lower rad hose is aftermarket and does not have the spring on the inside. the hose could be collapsing preventing cooler fluid to enter the motor. check you lower hose and see if you have the spring

wgyouree

It shot up very fast, and did also shoot down very fast. And actually, the guy who sold it to me did say he replaced the radiator hose himself. This is probably the issue! Where's the best place to get a stock hose with spring? local auto parts store?

So, is it worth it to replace the water pump and thermostat at the same time or should I just wait for it to start "weeping" before replacing it?

96 XJ Sport

Those items you mentioned are all great things to do on the 4.0 and will save you headaches later. You'll be glad you did them. If that lower radiator hose doesn't have the spring, your local auto parts store should be able to help. I got mine at AZ and it had the spring. Oh, and welcome from KY!

Eric

warthog

i agree, while your coolant system is drained, i would go ahead and replace those items and do a full system flush,

as far as the hose i guess it all depends on your local auto parts store. i called AZ, Oreillys, Advanced Auto and all said there hose did not have the spring. i finally called the dealer and made him call his parts house to confirm it had the spring, it did. they make you pay for it before they will order it so i would make your local dealer call and confirm also.

wgyouree

Thanks for all the great info guys! I've been reading this forum for awhile now, and it was one of the deciding factors when I bought my XJ. Ya'll are extremely knowledgeable and helpful! I'll go ahead and start ordering parts and talking to the dealer. I think I'll just get it all done at once, I want this machine to pur for at least another 200,000 miles. I'm replacing all the fluids anyway, so she'll have a clean start on the maintence schedule. I'll start a build thread when I get to the good stuff, like the rear disc brake conversion

98 JeepJeep

just a though but is the Elec fan coming on when the A/C is on??

Troth

Ya the electric fan is a good thing to check, a new thermostat could make a significant difference. I have heard of jeep owners swithcing those out and dropping 40 deees or so its really easy to flush the radiator of rust just by removing the wing nut and blasting it out with a hose. Sounds like your jeep is working hard with th 4.5 lift. ever though of hood scoops with hood vents behind?

mobilecherokee4

wow you have a spitting image of my jeep or at least the specs, ive got a black 1999 classic 4.0 I6 and mine did the same thing as well, i just flushed the radiator out replaced the fan clutch(which i was missing) and now it cools fine, i live in alabama so it gets hot!!!! and it is probly your bottom rad hose mine did the same thing

wgyouree

I just went and ordered both new rad hoses, top and bottom, from the dealership and made sure they include the springs. Are both the top and bottom hose supposed to include a spring? The guy in the parts department at the dealership seemed to think it was just the top hose.

Also ordered the transmission cooler, only $46 and it's gonna take a few weeks so I figured I'd time the rest of the work around that arriving. New radiators are pretty expensive, the one I was looking at is about $300, so I might just wash out the existing radiator and reuse it, but then I'm not sure if it's a good idea to install the transmission cooler in front of the existing radiator (will it block air flow?) or if I need a bigger radiator. It looks like it's just thicker, not longer or taller, though so maybe the airflow with a trans cooler wouldn't be an issue...

Also thinking about replacing the fan clutch at the same time as the water pump, since I'll be right there anyway, and the thermostat isn't expensive, so I may just install the 180* hi-flow.

Anyone know if the 180* hi-flow is a good idea or should I stick with a 195* like stock?

The electric fan seems to be working fine. It comes on when the vehicle starts warm, and I can hear it kick in occasionally.

Actually, I've been running around town in the thing a lot the last couple of days in the heat, doing 70 with the AC blasting, and it hasn't gotten over 212 again. I really think it's the spring in the hose, so it seems like it could just happen again at almost anytime without that spring.

Maybe I'll just do everything except the new radiator and then if I run into a heat problem again, install the 3 row radiator at that point. The rest of the stuff is just so cheap and easy to install there's almost no reason not to do it, it does have 137k on it and I want it to last a long time.

mobilecherokee4

keep the 195t-stat, mine has 137,000 on it too we have like that same jeep! hopefully wou wont have to buy a new radiator, just do all that other stuff and you should be runnin good

wgyouree

Cool, I'm gonna wait on the radiator. But I got the new rad hoses today and the top one doesn't have a spring in it, but the bottom one does. Either that, or it's just really far down in there on both ends. The spring in the bottom hose comes almost all the way to the ends. Is the top hose supposed to a spring that is visible from either end?

98 JeepJeep

never seen a upper hose have a spring in it...the lower is suction and top is return...would be no need for one.

wgyouree

Well that's good and bad. That means the hose I've got is good, but it might also mean that my problem is not the lack of a spring in a hose because I'm fairly certain the guy who sold it me replaced the top hose. Oh well, I'll be replacing so many parts anyway, something that's broke will be replaced in there somewhere I'm sure

Hop-up

Try and find a laser thermometer! I have a 96 with the 4.0 and have been having cooling problems for a while. Turns out my radiator had a 20* difference from the top to the bottom. I got a new 3 core from radiators.com TO MY DOOR OVERNIGHT for like $200. Also put in a new water pump, tstat and hoses.
Just installed a permacool electric fan today because my mechanical fan jumped up and punched a hole in the brand new radiator.