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Rockridge 4WD IS Taking Zone Offroad Suspension Lift Kits BLACK FRIDAY SPECIALS!! You asked, we deliver!Rough Country Lift Kits and Parts!

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Unread 08-02-2014, 02:36 PM   #1
Mowgli25
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Running hot and p0300

I've having two issues with my jeep

The first is a p0300 code that comes up only at 60mph if I go faster or slower it doesn't happen. I replaced the plugs and it's still happening although it seems not as often but that may just be me

The second is when I'm going slow or stopped my engine temp has gotten as hot as 240. When on the high way it gets back down to 220or so.

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Unread 08-04-2014, 04:31 PM   #2
Mowgli25
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Anyone?
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Unread 08-04-2014, 11:23 PM   #3
JealousDad
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On the temp problem it sounds like an airflow problem; I would check out the fan clutch.
The misfire code could be any one of a dozen things. It could be a clogged cat, or a bad O2 sensor, bad CPS, or the wrong plugs for the engine. What brand of plugs did you install?
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Unread 08-05-2014, 07:47 PM   #4
Mowgli25
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I replaced the fan clutch since I checked it one night and I was able to frespin it. I did check it a few more times after that (always cold) and it spun with resistance. I figures that may have just been a fluke that it frespun that one time but replaced it anyways. The new one spins with the same resistance I think. But I have noticed my idle temps a little lower but still in the 220-225 range.


Driving on the highway today for 3 hours I was having it get very hot. 226-228 was my normal range and it would spike at 230.

I have a ultra guage that's how I'm getting real never not just from the guage on the dash
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Unread 08-07-2014, 10:46 PM   #5
Mowgli25
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I'm starting to think one of the gauges may be off. This is where the cluster gauge is and the ultra guage is reading at 225-230 with doesn't match up
image-702050763.jpg

image-1527788617.jpg

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Unread 08-08-2014, 02:28 PM   #6
Speed94
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check the crank position sensor
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Unread 08-08-2014, 03:46 PM   #7
JStMarie
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You should stick with the cluster gauge when diagnosing a temp issue. It has a built in hysteresis that will help to keep you from chasing ghosts. The actual temp of course fluctuates under changing conditions as the system chases to compensate (T-Stat opens and closes). Any one instance in time your temp may be 10 or 15 degrees high or low. From a diagnostic standpoint you want the average temp over 30 seconds or even a minute, which is what the cluster gauge is giving you.

Your cluster gauge should, once the engine is warmed up, read 210 +/- nearly nothing. A needle width fluctuation is fairly normal. More than that and you should be chasing a cooling issue.

Also, most veterans can dial themselves to the problem by describing the behaviour of the cluster gauge better than the instantaneous temp of an ultra or ultra like device.

Given your symptoms it sounds like an airflow issue as JealousDad indicated. Since your fan clutch is new perhaps focus on obstruction? Is there anything blocking airflow through the grill? Also, added heat from an unusually hot CAT could cause your issues as well. If you are dumping more unspent gas than normal into the CAT it could run unusually hot and your P0300 code may be an added symptom that this could be happening.
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Unread 08-08-2014, 06:57 PM   #8
Mowgli25
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We'll new issue now. I did replace the termistat today. After two try's it's bolts down and good to go The temp now when at idle is 210-212. Driving around under 40 it stays about 210-215. Once I get onto the highways and drive for 15 mins or so going 60+ the temp rises back up to around 226. Once off the high way it stays around that temp and takes a very long time to cool down again.

It is 98deg out side with street temp of maybe 105. The ultra guage is not a programmer or anything is just a digital read out of everything that plugs into the OBD port
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Unread 08-08-2014, 07:03 PM   #9
JealousDad
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Did you put a "fail safe" thermostat in by any chance? They are known to fail and stay all the way open pretty quickly in our jeeps.
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Unread 08-08-2014, 07:23 PM   #10
Mowgli25
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It was from advance auto parts. I've only driven it for 90 mins since install
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Unread 08-08-2014, 11:28 PM   #11
Mowgli25
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I guess really the only things left are radiator, flush, or water pump.
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Unread 08-09-2014, 08:05 AM   #12
JStMarie
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Quote:
I guess really the only things left are radiator, flush, or water pump.
First of course you need to fix the faulty thermostat you just installed. If you are that low in temperature after 10 minutes then something is wrong with your thermostat. It is likely stuck open. Buy a non fail safe version rated for 195 and install it. Your engine depends on a controlled temperature curve after start and predictable temperature control during driving and will run poorly if you run with an improperly functioning thermostat.
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Unread 08-09-2014, 10:54 AM   #13
Mowgli25
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Quote:
Originally Posted by JStMarie
First of course you need to fix the faulty thermostat you just installed. If you are that low in temperature after 10 minutes then something is wrong with your thermostat. It is likely stuck open. Buy a non fail safe version rated for 195 and install it. Your engine depends on a controlled temperature curve after start and predictable temperature control during driving and will run poorly if you run with an improperly functioning thermostat.

I had to re read that a few times and then relised I was typing 110 not 210. That was a typo. I fixed it.

Still running hot though.

I didn't use a fail safe one!
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Unread 08-09-2014, 01:51 PM   #14
JStMarie
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That certainly changes things.

226 is not all that high. Just curious, what does your cluster gauge look like when running that hot?
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