What temperature does your Jeep run at?
- Thread starter Russ_S
- Start date
The best part about this whole discussion is basic effort expended for the intended result. Not that anyone should but if you bring me your rig for a cooling system overhaul and insist that I use outside of my elected norm complement of parts, two things may happen.
The first is I will decline the job unless I take pity on you. The second is if I don't decline, we'll have a very serious discussion about what to expect on both sides. I don't expect it to work and you don't get to expect me to fix it for free if it doesn't. Not sure how that gets overlooked so readily.
The fact that I have a zero defect rate with OEM parts matters to me greatly.
I've been closely following threads like this. I've never been happy with the fact that when the outside temp was above 60° F and at sustained highway speeds, my needle would move to the right edge of the zero in the 210 label on the gauge.
The radiator, hoses, water pump, thermostat, and radiator cap were all replaced new when a new long block was installed two years ago. Temperatures were not erratic, indicating neither a bad sensor nor air in the system. I'm running a Stant 18lb radiator cap, but swapping caps made no difference. Coolant is fresh and of the proper type and 50/50 mix. Coolant level was stable in the bottle with no boiling or gurgling when hot. The only thing that wasn't new was the fan clutch. When I would slow down, the needle would fall down to the center mark, so I assumed the fan clutch was working as it should. It wasn't overheating, just running hotter than maybe it should.
However, the repeated statements by many here that a properly functioning system should keep the needle close to the center mark bugged me, so I bought an OBDII reader and downloaded the Torque OBD app and started monitoring.
In checking the dash gauge to the reality of what the sensor was reporting through the OBD, what I found was that the temperature range indicated by the my dash gauge is about 195° F when the needle is on the left edge of the "2" and was at about 230° F when the needle was at the right edge of the "0". Needle dead center is 212° F.
Then I kept reading @Jerry Bransford posts where he recommends trying to spin the fan when the engine is hot (but not running!) OK, I could move it pretty easily, but it didn't "spin." So I checked it with the engine cold and found about the same resistance to movement. Concluding that this probably just wasn't right, I bought a new fan clutch and spent 45 minutes changing it.
What a difference.
The temp gauge needle now rarely moves above dead center unless I'm hauling it down the highway in really hot temps. I went off-roading the day I changed the fan clutch and the needle never even got to center point even though it was all slow-crawling and idling in 102° F heat.
The radiator, hoses, water pump, thermostat, and radiator cap were all replaced new when a new long block was installed two years ago. Temperatures were not erratic, indicating neither a bad sensor nor air in the system. I'm running a Stant 18lb radiator cap, but swapping caps made no difference. Coolant is fresh and of the proper type and 50/50 mix. Coolant level was stable in the bottle with no boiling or gurgling when hot. The only thing that wasn't new was the fan clutch. When I would slow down, the needle would fall down to the center mark, so I assumed the fan clutch was working as it should. It wasn't overheating, just running hotter than maybe it should.
However, the repeated statements by many here that a properly functioning system should keep the needle close to the center mark bugged me, so I bought an OBDII reader and downloaded the Torque OBD app and started monitoring.
In checking the dash gauge to the reality of what the sensor was reporting through the OBD, what I found was that the temperature range indicated by the my dash gauge is about 195° F when the needle is on the left edge of the "2" and was at about 230° F when the needle was at the right edge of the "0". Needle dead center is 212° F.
Then I kept reading @Jerry Bransford posts where he recommends trying to spin the fan when the engine is hot (but not running!) OK, I could move it pretty easily, but it didn't "spin." So I checked it with the engine cold and found about the same resistance to movement. Concluding that this probably just wasn't right, I bought a new fan clutch and spent 45 minutes changing it.
What a difference.
The temp gauge needle now rarely moves above dead center unless I'm hauling it down the highway in really hot temps. I went off-roading the day I changed the fan clutch and the needle never even got to center point even though it was all slow-crawling and idling in 102° F heat.
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Shoulda just installed a 160 degree thermostat and been done with it.
It is mentioned in a post above about electric fans in the hood. Does anyone have recommendations on where to get these or have pictures. I have an LS installed and it takes up more room and restricts air flow. Hood fans or some sort of vents sound like a good idea. Certainly can not hurt.
Glad you posted this, some people claim a bad fan clutch has no effect on the highway and obviously in your case it did. In fact at highways speeds it seems to have had a larger impact on temperature.
Just for future readers, Blaine was of course tongue-in-cheek kidding when he said that.
I puzzled through that with the clue being there should be significant resistance to spinning the fan by hand when the engine is hot. That makes me think that when it's in early stages of failure, it free-wheels just enough to affect both the slow and highway speeds some, while highway-speed air flowing through the radiator is still able to keep the engine from over heating. If it was worse, I'm sure there would have been over heating at idle or when going slow.
Guessing you missed that sage bit of advice from goober in Montreal?Just for future readers, Blaine was of course tongue-in-cheek kidding when he said that.
It should be obvious to you now that the fan clutch determines how much air goes through the radiator even on the highway. There is plenty of great info on this site about the cooling system on our Jeeps. I wouldn't dwell on this too long on this issue, it isn't a big deal.
Screenshot sitting in the drive after a 12 mile run up the interstate at 75 mph. I live less than a mile from where I get off the highway. It dropped from it's high of 213.8 to this temp in that distance. Outside temp is 91 F.
Just for future readers, Blaine was of course tongue-in-cheek kidding when he said that.
Damn, I just pulled out my 195 and installed a 160
Just put some stop leak in there. It'll make it work like a 195.
I agree.
For me, it's about understanding the why and the how in addition to the what. In this forum, as with all automotive forums I've participated in, good and bad advice gets mixed together and usually there are people who offer single-solution answers to multi-cause conditions. It takes filtering.
And now everyone will tell everyone to change out the fan clutch first.
Exactly.
Just like on a Honda Valkyrie motorcycle, the first response to a no-crank or crank-no-start is advice to clean the starter switch. But it's usually really a battery problem and the tell-tale is that it you'll have lights and horn, but not enough juice to fire the coils. A jump start confirms.
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