WK overheating...checked everything! - JeepForum.com
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post #1 of 11 Old 08-23-2015, 01:58 PM Thread Starter
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WK overheating...checked everything!

Hi all,
I'm very new to this forum so I hope I'm not breaking any initiation rules...

Anyway...my 2006 WK 4.7 with 101,400 miles started overheating on Thursday (today is Sunday). Except for a new catalytic converter (my fault, ran over something that damaged it) the thing has been bulletproof since I bought it two years ago (used, 55,000 miles). Troubleshooting done:
1) Replaced thermostat. Back-flushed the whole system (with Prestone radiator cleaner and flush/fill kit) then filled with Zerex coolant, burping the cooling system per the service manual instructions. Car temp was fine at idle, but overheated after about 3 minutes of driving no faster than 45MPH. Came back home just before gauge read overheat.
2) Car sat overnight, checked the dipstick. Oil looked fine, no signs of coolant.
3) This morning, replaced water pump with a Gates 43263 from Amazon. Then flushed the radiator using a garden hose, the flow seemed fine. Filled with fresh coolant/distilled water. The engine was cold, so I was able to fill it to capacity, but this time it took A LOT longer to fill it to the point where it came up to the bleeder valve. Took a test drive, began to overheat. Pulled over with the heat on, but it wouldn't cool down. Waited five min until the needle moved about 1/4 to the left, then drove home and left it idling with the heat on. It started to cool down to normal.
4) Ran a compression test on all 8 cylinders. Max variation was about 8PSI. Not ideal but seems okay.

I'm stumped. Before I replace the radiator and/or the head gasket, I wanted to run this through a few more heads. I hate to think I'd have to pour more money/time and still end up with an overheating engine. I'd appreciate any input...

Thanks all!

ucfhall is offline  
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post #2 of 11 Old 08-23-2015, 02:28 PM
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2008 WK 
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Could be a faulty sensor. Use an IR thermometer on the block or radiator hose and see what that says.
Birdhouse is offline  
post #3 of 11 Old 08-23-2015, 04:29 PM
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2008 WK 
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I had an 01 Xterra with a similar headache.

The rad coolant would heat up, expand, and enter the expansion tank. The expansion tank would cool but wouldn't introduce the coolant back into the rad. I had to siphon my coolant, every day, from the expansion tank to the rad again.

It ended up being caused by a crack in the rad that was facing the back of the rad. Look for coolant spillage. The pressure would push some out. Coolant seems to dry whitish. The crack would mess with the pressure required to pull coolant back into rad.

Are you losing coolant out of the rad? Might be a similar problem that I had.

In addition, I had a head gasket problem with my Xterra and the thing ended up overheating after the rad was replaced, catching me off guard. Engine fried. White smoke pouring out exhaust. RIP. It was free though and ran for 3/4 of the year, so not much of a loss.

That's all I can help with. Good luck.

2008 Jeep Grand Cherokee CRD
GDE Hot Tune, DPF Delete, Turbo Res. Delete, Exhaust Res. Delete
plunix is offline  
post #4 of 11 Old 08-23-2015, 05:37 PM
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Took me about two months to fully burp my cooling system after a new water pump. It would randomly overheat and then the temp would get back to normal.

2010 3.7L, 4XGuard Matrix, Fastman TB, TB Ground Mod, Injen CAI, 255/60/18 Nitto Terra Grapplers, Bilstein Shocks & Struts, Cruiser Alloy Wheels - Switchblade, Stillen Brakes, Cargo Light Strip Mod, Electric Ashtray Mod, Jet-powered, Monkey Navigated...
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post #5 of 11 Old 08-23-2015, 07:25 PM
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2015 WK 
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Just had this issue with my '05 with 155k

replaced the t-stat, water pump and fan clutch - have not had an issue since (although my mechanic said the the fan clutch was a sum***** to replace).

Have not had an issue with the overheating since.
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post #6 of 11 Old 08-24-2015, 08:34 AM Thread Starter
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plunix- no coolant loss whatsoever.
Birdhouse- I'll do that...do you happen to have an idea where the sensor is?
BMoreGC- Tried all that except the fan clutch which seems to be okay when I try to spin it by hand. Plus if the fan clutch was bad, it would probably be overheating at idle, not when I drive since the airflow at speed takes the place of the belt-driven fan.
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post #7 of 11 Old 08-24-2015, 01:32 PM Thread Starter
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Never mind...found the sensor, and replaced it. Gauge still indicates overheating...UGH.
ucfhall is offline  
post #8 of 11 Old 08-25-2015, 06:11 AM
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be sure to monitor the coolant level at the rad cap, and open the bleeder if you add any.
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post #9 of 11 Old 08-25-2015, 07:04 AM
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have you tested the pressure on your rad cap?
Are you sure there is no blockage in your radiator?
JKM is offline  
post #10 of 11 Old 08-25-2015, 07:09 AM
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May want to also run another pressure check. I had a similar problem after my radiator was installed. After the 3rd time having pressure checked over 3-4 week period the dealer found a gasket leak. Not sure why it took 3 times but i guess the leak was just very small the first time and by the last time it was large enough for them to find...or incompetence the first two times?!?
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post #11 of 11 Old 08-26-2015, 01:54 PM Thread Starter
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So long story short the issue fixed itself...I think I just didn't burp it correctly; I put the old thermostat back on so I could return it and the engine was totally cold, so that must have helped the coolant fill in all the way. Thanks everyone for the help!
ucfhall is offline  

4.7 liter , help please , overheating , wk

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