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frostbiker

2000 WJ Cooling Issues

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Hey gang, I could use some help if you don't mind. I searched this forum and scoured the net last year to help replace the radiator on my WJ. New hoses, coolant, fan relay and thermostat, too. Turns out, the previous owner was unaware that the mopar coolant in the radiator was horrible stuff. After 10 years it just clogged the entire system. Coolant level is fine now, no leaks that I can determine. Fans are spinning at idle, A/C is cool (was purged and serviced when radiator was replaced last year).

 

Fast forward to yesterday. Check engine light pops on in the AM and the temp starts creeping in the PM. Borrowed an OBD at the parts store and showed no faults. I'm thinking fan relay or thermostat went bad, or even the A/C unit is starting to go. It has been hotter than Hell's Gate in Houston since....Christmas, and it has been taxing my A/C. I'm a court runner, so I drive quite a bit during the day. Fifty miles most days on street and highway.

 

Checked with my dad, who's the end-all-be-all of shade tree mechanics. He recommends starting at the thermostat and replacing with a cooler one. Okay. Easy-peasy for me. Might as well flush and replace coolant while I'm at it. I'll double check that relay under the light since I'm feeling frisky, too.

 

Let's brainstorm now! Throw some ideas my way that are proven methods of helping my truck run cooler or stay cool. Also, how can I test the water pump and other parts of the cooling system to make sure they're operating efficiently?

 

Thanks for the help.

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First chekc and make sure the electric fan is running then you may need to check your electric fan relay. They are known for going out. Sad part is for 99-03 the relay is under your pass side headlight. The 2 speed fan itself goes out and kills the relay, odds are if you put another relay in it may kill that one to. A replacement electric fan is like 300 bucks!

 

I have an 04 and my relay is now two of them up in the power dist center. My fan only runs on low. I opted to install a OEM fan and fan clutch. I can now sit in traffic in phoenix all day long and not have it go above 210.

 

Link to fan relay page

http://www.jeepslimited.com/index.php?option=com_content&task=view&id=37&Itemid=127

 

link to adding mechanical clutch fan

http://jeepsunlimited.com/forums/showthread.php?p=4377394#post4377394

 

if you do any towing or heavy loads in cab I would suggest the mech fan anyways.

 

Hope this helps

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I replaced the fan relay last year. That was the first thing I did. Fans are running when at idle, otherwise, the temp would be much hotter. It's not getting much over 210 right now.

 

I also noticed a while ago that after two hours in a dark, underground parking garage that my engine block was still hot enough to cook on. Was also searching around online about related water pump issues and found a large-ish (quarter size) spot of rust/crud and a nearby pinhole on the cover of the water pump. Was reading on another forum where someone's water pump was corroded all to heck inside and that limited the flow of coolant and caused a head gasket failure.

 

I'd love to get these coolant issues knocked out before I even begin to contemplate the 'death wobble' issues I have.

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how many miles on her? 4.0 or 4.7?

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beyond what was already said about the possibility of a bad electric fan...

 

with the 4.7, make sure you are filling the system to the top of the radiator, then with the cap off, fill from the bleed screw till it comes out of the radiator filler neck. then cap the radiator and replace the bleed screw. otherwise if you just fill from the radiator you leave air in the system.

 

does turning off the A/C immediately let it start to cool down? if so then maybe bad compressor, but i doubt it.

 

at that mileage, i'd do a chemical flush and just replace the water pump and thermostat to start with. there's no reason to get a cooler thermostat, that might help performance (according to some), but it won't make a system with a problem work better. get a factory thermostat.

 

i have no idea how you check to see if a water pump is getting lazy or no longer working at full capacity, but at that mileage it could certainly be starting to go or have the fins corroded away at least. it's an inexpensive preventative maintenance thing to do even if it doesn't fix your issue.

 

at that point, you will have cleaned the system, have new radiator/thermostat/pump, so then if you still have issues:

- do a cooling system pressure test to verify no leaks, you can borrow the tool from autozone/etc.

- have a shop use a sniffer, or you yourself get one of the die type kits, and test for a compression leak

 

good luck!

 

oh - also curious about the MIL - did the light stay on? is it still on? or was a temporary thing? did you try with the key trick to get codes?

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oh, mines the 4.0

 

I had replaced every single coolant part on mine inlcluding a HD waterpump. I still had overheating issues and for me it was the 2nd spped of the E fan not coming.

 

Sorry if I misled ya.

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ksmith, it takes a minute or two, but the temp does go back down when the A/C is off. I've been running the a/c in auto at about 69* all summer. That may be a part of the contributing factors as it is taxing the system. I've since taken it off auto, set the fan to low and opened the outside air circulation. It seems to help keep temps around 230*.

 

I do know that the water pump will get replaced. Close observation shows a quarter size rust pit that goes pretty deep. Looks like there are a couple of pinholes there, too. I'm going to be 'better safe than sorry' and replace that this weekend.

 

Ksmith, I've been meaning to ask about your build project. I'm putting in my old Yaesu FT-8100 radio remote mounted above the ashtray. Did you end up using the firering coax, or another? What about connection to the Diamond antenna, what is working for you? I'm currently running a Yaesu VX7R to an MFJ 1722 on the roof and only just barely able to 'chunk' 2m repeaters in the area. Don't even ask about 440. Your install makes perfect sense for me to try. Need to be able to operate with better equipment without having to scrape the ceiling in the parking garage.

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and the 'check engine' light is still on. How do I get that to STAY off?

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and the 'check engine' light is still on. How do I get that to STAY off?

 

do the key trick to pull codes - no idea why the reader didn't work for you, but you MUST have a code stored if the light is on. you turn the key from "off" to "on" three times and on the last "on" leave it there and the digital odometer will read out each stored code, one at a time. (note you do this with the vehicle off, and you don't move the key to "start", just to "on" each time). tell us what codes you get back.

 

 

Ksmith, I've been meaning to ask about your build project. I'm putting in my old Yaesu FT-8100 radio remote mounted above the ashtray. Did you end up using the firering coax, or another? What about connection to the Diamond antenna, what is working for you? I'm currently running a Yaesu VX7R to an MFJ 1722 on the roof and only just barely able to 'chunk' 2m repeaters in the area. Don't even ask about 440. Your install makes perfect sense for me to try. Need to be able to operate with better equipment without having to scrape the ceiling in the parking garage.

 

i used the diamond antenna C213SMA mount & cable for my radio. i've had no problems with it or the antenna. i got mine from a local shop, but these guys sell everything too: http://www.expeditionexchange.com/diamondantenna/

 

P1000316.JPG

 

of course the roof is a better place due to ground plane, but i just didn't feel it was practical.

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