Yep, 230+ in 2 miles is definitely toasty......with all u've done, I'm stumped. You must be a 0.001%'er. LOL.....sorry, I know it's not funny.

 

And just when I thought I had it figured out to. Blocking air flow (cardboard in front of the radiator)raises the temp. So blocking the coolant flow lowers it.

Just kidding. I'm just bored.

I'm kind of figuring if you do everything possible to the cooling system and still have an overheating problem your talking internal engine problems. Flow restriction/restrictions that flushing won't remove (ex:head gasket covering or partially covering a port). Or heat caused by friction within the engine that even a beefed up cooling system can't handle.

 

Well said.......there's some cause that we just can't easily see.

99.9% of the time the "big 4" (new rad, new pump, new clutch and new stat) will cure overheat....but then there's that stubborn 0.1%.

 

I'm part of that 0.1% myself.

 

Hey Brother, I'm having the same issues as you are. If I could have wrote a story, it would be yours. I've done just about everything you've done and am still hitting a wall. One of the things that helped my engine stay cooler was going to the junk yard and getting a spring for the lower coolant hose. This goes on the inside and keeps the hose from collapsing. they don't sell them at the store so you have to hit the junk yard. The next thing I will be trying is to install hood louvers, they are a little pricey at around $200 bones but I figure helping the air flow through the engine compartment and out the hood couldn't hurt, plus they actually look pretty tough. I think this is one of the jeeps biggest problems is air flow. Makes sense to me. Hope this helps or at least gets you in the right direction.

 

I've got a set of 280zx hood vents I need to get around to installing

 

Todays temp in Phoenix 116. Just came in from 30 miles on the freeway, engine temp 210 open system on renix' a/c on. Spring in lower hose,hood vent and that funky little air dam under the bumper intacted. That air dam helps to creat a lower presure area under the hood. At road speed air will take path of least resistance. That means under the bumper to the engine bay.It will get up to 220 on a little 8% grade we have here that is 8 miles long air temp around 105.

 

see post #27

 

Yep, I agree with #27 as a possibility.......and like I said "some u can't easily see". With any motor that has ever overheated, even just once, one can never rule out a possible crack somewhere.

 

Moved my entire fab shop, excluding an engine and my fab table, to my new location with the XJ this week.

Been above 90* and my XJ had over 2k lbs in it 3 times, for 40 miles. Temp never ran above 210*

Still seems to be working.


I forgot who said it, but 220* up I-70 (Floyd Hill) is not running hot. Any XJ with cooling issues I have owned overheated 1/4 way up this hill. The stock e-fan doesnt kick on until 217*-220*.....and not to mention, my XJ is far from stock.

The one thing I did notice is, when I am going down that same hill in 4th or 5th gear, it will cool down to 180. I have a stant 195* t-stat in it now. Still seems like too much flow to me.

 

"although his XJ isn't overheating,220 is still seems too hot especially after everything else he's done to the system."

What I should have said was "still seems too HIGH".

You say your XJ's far from stock. Any way it could be flowing the same as a stock XJ some how? With the restricter. So you thinking on restricting it more?

 

180 coolant temp in 90+ ambient with a 195 t-stat may indicate a bad stat or a bad gauge. A stat that is stuck partially open (never fully opens or closes) can cause both undercooling or overheating depending on ambient temp and driving conditions. A properly functioning 195 stat is essentially closed at 195 coolant temp, thus virtually stopping flow thru the rad. When the stat's closed, coolant is continuously circulating thru the block/head via the bypass loop and coolant temp inside the motor is rising.

The sole/single purpose of the t-stat is to maintain minimum coolant temp by stopping/restricting/limiting/slowing coolant flow to/thru the rad. The other cooling system components, their condition, along with ambient temp and driving conditions determine maximum coolant temp.

 

Good explanation.

 

I am very well aware of the purpoe of a t-stat. Temp guage is good and has been confirmed with an infared guage.

And I have tried multiple t-stats and no t-stat at all. Same results.

Im past trying to fiure it out. It doesnt overheat anymore.

I posted my solution to the problem so others could give it a try. It worked for me, so Im sure it will work for others.

Thanks for the help.<-----onlinetoolong

 

Dropping to 180 is what's puzzeling to me......