Some cooling questions and a little rant...

here's the quick background, buy the XJ from my buddy in Jan of this year.....he tells me he put a GDI in it right before he sold it to me, "it was starting to run hot" i didn't really think about it too much, my old 87 ran hot all the time and eventually blew its top after 200K.....i digress....
so as the weather has gotten hotter here recently in VA the temp guage has started to rise.....i am busy at work and planning my wedding, so time is short....kept slowly climbing, now it was getting pegged at that first white line after 210, it is a 97 by the way....not sure what temp that line represents but it never has gone past that....so i did the widely known "not recommended" and put in the 180 t-stat and went to jiffy lube and got the 60 dollar flush.......of course you know it still goes to the first white line after the 210 mark,
1. the aux fan does come on and cools it down to almost 210 and then goes off.....
2. the jeep has 57K miles on it!!!
3. upper and lower hoses replaced with new gdi
4. what to do???

thanks fellas

is the mechanical fan engaging and pulling air?

put the electric fan on a manual switch, and bypass all the sensors, it keeps my 90, with the stock style cooling system for that year below 210 almost always.

Try using a more dilute mix as pure water is a better conductor of heat. A little watter wetter may help as well.

Pull the radiator and have it rodded out by a radiator shop. Some GDI radiators have been found to have restricted tubes out of the factory (quality control is not what you expect). The cost is usually only a little more than what you paid for the flush, although you need to take the radiator out and deliver it.

BTW, did it sound like a toilet when they closed the register at J-Lube?

Install a heavy duty radiator... The only way to go if you want to keep the temp down. Mine never gets to 200 even towing after the new radiator. Also, check to make sure that the o ring on the pressure bottle is OK. More pressure means better cooling too. Something like 3 degrees for 1 PSI as I recollect. I had a hell of a time getting mine to cool until I replaced the pressure bottle cap even with the new radiator. After I got everthing working I thought my coolant temp sensor went out because the electric fan never came on any more... it's fine, the engine just never gets past 200 anymore and it comes on at 210 or 215.

I agree. Put a GDI 3-core in it. Chances are, you have a 2-core in it now. The 3-core will give almost 50% better cooling, and the cost is about $120.

I don't care what they say. The GDI is crap. I have two of them in my storage unit collecting dust. One had some bent fins (go with Bombproof Motor mounts now or pay more later ) but did "ok" with my stock 4.0. With the stroker, I bought a new GDI just to be sure to keep everything cool. Nada!, it couldn't keep an Eskimo cold.
Had a rad shop check it (because of the reported shoddy workmanship in the assembly of the GDI I figured it was plugged up). They found about 5% of the tubes plugged. It just was not up to the task.
The Radiator shop guy then showed me the 3 core GDI next to the 2 core Modine. There is a big difference.

The GDI uses three 1/4" tubes while the Modine uses two 5/8" tubes. That’s .75" vs. 1.25" of tubing to keep things cooler and the larger tubes don't plug as easily. The Modine made a big difference in my stroker's temperature last July.

IMHO, dump the GDI and get a Modine.

Bones :skull1:
#6

if the fan is kicking off, might consider replacing the sending unit in the t-stat housing.

ok, additional info,
as already stated, GDI in it, "bones" you suggest the modine....
will start looking in that direction, i will do a search and check the prices......
ran at the first white line all the way home from work lastnight, park and go traffic on the beltline anyways never went above it, A/C on the whole time, got to 92 here yesterday with about 85% humidity!!
pull into my apt, turn off A/C, of course aux fan keeps running because it is so hot, sat there for five minutes, the aux fan could never cool it down it was so hot! I opened the hood to look around, and finally with the hood open the aux fan was able to bring it down in temp......this morning driving to work it is 0530 and cool, it goes to 210 and sits there the whole way......

1. So the GDI must be plugged????
2. There is only 57K on this jeep so that makes me think the Mechanical fan and waterpump are fine, turned the fan by hand, was plenty of tension and no dripping from waterpump....
3. Well I am leaving friday for two weeks, so it will sit until then, Looks like I will be going the Modine route after that...."bones" you will recieve a nice PM if that doesn't work
"Ed", I know already, but in a bind and three hours from home, I hoped the j-lube flush would work.....think I will spend that 60 bucks toward the modine though and just junk the GDI...

sitting here trying to get some work done, and this subject is just bothering the hell out of me.....
are all newer XJ's running hot too? did the remake of the XJ solve any of these cooling problems?? or am I just getting the short end of the stick?
would love to hear from some newer XJ guys who haven't modded their cooling systems at all, yours probably runs cool as hell right???

Mine ran hot because of dirt and sand in the radiator. Did he off-raod it? If so, pull the electric fan and wash it out from both sides with a garden hose. You'll be surprised how long dirt will continue to run out while your doing this. Cured my overheating problems.

Like I said, swap the radiator for a 3 core HD and make sure that you don't have a pressure leak. Solved all my problems and the XJ stays a hell of a lot cooler than it did when it rolled off the assembly line. The guy that had the Chief before me killed the engine with all the overheating. Try not to run it hot if you can help it... your engine will thank you.

I'd neglected the stock radiator on my '97 for way too long and just gave it the major flush job last weekend. It was pretty ugly but I haven't ever had a problem with it. It ran consistantly just below the 210 mark (190-200 range?). In the hottest weather here in SoCal with the a/c going full blast it sits right on the 210 mark. The Rad flush hasn't seemed to change anything either way, at least on the temp gauge anyway.

Make sure the fan clutch is operating normally!

I have 69k on my 99 stock cooling system minus the 195 t-stat. It runs right below 210 everywhere on the road. When I take it offroad in the texas heat I creep up to the whiteline after it but never past.
Kyle

so, any idea what temp that white line after the 210 mark represents??
more info,
I drove down to raleigh today, about 3 hour drive, it was 95 today, so i had the a/c on, it went to the white line like usual then doing 75 down the freeway it started to creep past it, i said screw it and just turned the a/c off, sweated to death the rest of the trip but it was between the 210 mark and the next white line the rest of the trip.....i hate this

A lot of late model cars are designed to run at 210 or slightly higher because it is more "efficient". Although I would prefer my rig to stay under 210 it isn't really cause for panic. Are you certain that your Temp. guage is reading correct, I would install a $10.00 mechanical temp guage before I spent any money on any "hard" parts. Also someone in this thread suggested watter wetter. It is a very good product and definetely worth a try. Also a good quality aftermarket water pump Is worth its weight in gold. They usually pump something like 25% more water than a stock version. I am not sure if any of the big names make any pumps for the 4.0, maybe some of the 4.0 gurus here could help with that.

good luck,

JJ

Hesco sells high volume pumps and other goodies..I have never used one, but at least the Jeep specialist there seemed to be very up to par on the technical stuff...I got some very good information when I was modifying the mighty 2.5.

95YJ,
I had a similiar problem, especially with the weather warming up here in So. Cal... Wait its always warm here! lol!!! Anyway I first changed the water pump (was going out!!) and T-Stat(180*) still ran the same. I then changed the fan clutch, my stock one was still in good condition though but changed it anyway(the old one is still in garage if anybody needs it!) and also flushed the coolant system with some fresh fluids, still would get hot with local driving in Los Angeles..... I finally broke down spent $99 bones and installed a GDI 3 row and now it dosent get up to 195..... Oh yeah I took my aircompressor and blew out all the bugs, rocks, and accumilated debris the was in the a/c condenser and tranny cooler. Since air passes through these items first, and if they are restricting airflow its not going to make it to the radiator.

Just my 35Yen

Scott Suyeto
Gardena, Ca.
Member #631