Update

I got a fan clutch yesterday morning and installed it. We headed out to Haspin Acres and all was sweet on the drive out. Even in the 20 minutes of stop and go through Indy, temps were stable at 210°-215°. When we got to the park, my temp started inching up during the first climb. When it got up to 230°, I started freaking out again and cranked the heat. Within fifteen seconds, it was back down to 210°. I had to continue the rest of the run going back and forth between heat and no heat in 87° weather in a black Jeep. Needless to say, it wasn't that much fun.

So, I am still perplexed, but I am now wondering if there is some buildup in the engine block somewhere that is restricting flow. I didn't drive it much today, but, in the ten or so miles that I did, it acted normal. I am heading up home tomorrow to mid-Michigan, so hopefully all is cool. I guess I'll find out...

 

my jeep is doing the exact same thing. i have no idea what is is. i have rplaced just about everything you have and had a coolant complete flush. still doing it. im in mid-mich too. crazy huh. im at a complete loss to what is wrong

 

There is some stuff you can add to your coolant that will make it turn blue if exhaust gases are getting into your coolant but I will have to do some research to get the name and manufacturer of the stuff

 

So it's kind of like that stuff they put in public pools?

 

Could be a partially or full clog water jacket(s) I had the same problem in my 99 cherokee and it turned out that ALL of the jackets were clogged except one...flow could be good every where else...

 

The only turn blue thing i know of is a head check kit and you dont put it in your coolant. you can get it at any auto parts store but not very cheap unless you already have the tool it works in. I read some where about a waterpump that flows twice the volume of water at idle and low rpms then flows normal flow around 3500 rpms (think it was at quadratech website) dont quote me though. any one used this waterpump yet? thinking about it but have not seen anyone talking about it.

 

You must be talking about flowkooler I personally have no exp with them other than a buddy has one on his xj unless its under a real heavy load it runs about 200° under load it runs about 210-215° I dont think the efan has ever come on because it got warm enough.Im plannig on running one on my stroker once I get it built. Hope this helps

 

At what temperature did the auxiliary fan come on? Did the auxiliary fan bring the temperature back down along with the heater/blower motor? Have you ruled out that the gauge may be off? Will the coolant boil if you don't turn on the heater?

 

I don't know at exactly what temperature the e-fan ends up kicking on, but it is shutting off when it gets back down to the 210°-215° range. I don't know if the on/off temp should be the same for the fan or not. Perhaps someone knows?

I haven't completely ruled out the gauge being off, but I don't think it is too inaccurate since at cruising speed it is steady at 210°.

I don't know if the coolant will boil or not, since I haven't felt comfortable enough to let it go much more than halfway between the 210° mark on the gauge and the next white mark over (245°?) without blasting the heater. So far though, I haven't had any coolant boiling.

 

hood vents? Mine does the same thing. It's my daily driver and it terrifies me. Im lucky to drive through town with no problems... then again the weather has been around the 90's with high humidity..

 

Have you replaced or thought about replacing the coolant temperature sensor in the thermostat housing? I don't know how expensive they are. Would a gun-style infrared temp sensing tool shooting at the thermostat housing accurately show you the temperature of the coolant at the sensor when the auxiliary fan kicks on?

 

I have thought about replacing the sensor, and will probably do so when I get back to Indiana on Thursday. More recently, it will run fine for thirty minutes or so, then the temp will just start climbing. I really wish I knew why...

 

The fan shroud is only $25 and makes a world of difference. Mine was cracked so I ripped it out and immediately started overheating. I put a new one in and overheating stopped. While I was at it I replaced the fan clutch just because.

 

Update

Ok, so I drove it up to Michigan and back. The drive up was mostly drama free, except for the fact that, for the last 60 miles, I had to have the hood popped to keep it in the 210° range. The drive home was less than stellar as I had to have it popped as soon as the speed limit went from 55 to 65 (most of the way home). It was sitting right around 210°, but started to creep up on me as soon as I started driving faster. Slowing down to a stop made the temp rise even faster.

Yesterday, we were doing some tinkering with it, and noticed the e-fan wasn't coming on when the gauge was rising during idle. However, I could flick the a/c on and back off, and the e-fan would stay on, but not really make it that much cooler. When I would crank the heater with the e-fan running, the temp came down fairly quickly, and the e-fan would then shut off ~212°. This leads me to believe that the sensor is bad at the t-stat housing (as 5-90 suggested).

Still, I don't think that the temp should rise that quickly no matter the circumstance. That being said, I got some of the Prestone Super Flush (of the 10-15 minute variety), and the back-flush kit. I'll probably try this today and see what happens, and if this doesn't do the trick, I'll probably replace my already replaced water pump with an upgraded unit. Any suggestions on which one to get?

Thanks all.

 

i have my e-fan hotwired, so if it's plugged in, it's on. if i don't need it, i just unplug it. i'm gonna hook it up to a switch sometime.

but for now, it's on all the time the key is on. if i burn it out, they're 10 bux at the junkyard.

you can also add some watter wetter, that should help.