awg

depends...not while moving along at road speed should be around thermo temp, but that is 100% normal for a hot engine while idling (or moving very slowly...in hot weather)

have a look at the FSM...the factory electric fan is designed by engineers to not even switch on till 221F (105C)

my OBD2 monitor shows it will rise to 108C (225F) and then come back down to 100C (212F)...this is idling in hot weather...that is the test

your temp should not rise above 235F, that is beginning to overheat..over 242F they will start to boil

these figures are from a very experienced Jeep technician who tested "hundreds" of XJs in hot weather with the dealer tool , and accord with my 3 x '96

My understanding is these temps are within modern design parameters and help fuel efficiency, I do consider the cooling system slightly marginal for very hot climates

dave1123

Modern emission standards require engines to run at 210* for maximum fuel efficiency and the injector system is programmed for that. Older engine ran a 180* for proper fuel evaporation in the manifold before entering the combustion chamber. Seeing as how water boils just above 210*, pressure is important and controlling engine temperature is a fine line between fuel efficiency and damaging temperatures. The 4.0L engine was eliminated from the lineup because it couldn't meet the near future emission standards set by the EPA. These standards are more closely met by small displacement high reving engines that are supercharged or turbocharged and now direct injected ones. These engines also have overheating problems because they are trying to squeeze every bit of power out of less fuel. Bottom line, they are trying to phase out gasoline engines, period.

Let's face it. Internal combustion engine technology hasn't changed that much in almost 150 years. However, there really isn't an economical replacement yet. These engines are made of metal that can be recycled. What do we do with a bunch of dead batteries? Electric cars are not cheap to build or maintain because they all rely on batteries that are expensive to make and not easy to recycle. In addition, they put a great load on the electric grid by being recharged with electricity being generated from fossil fuels. I'm all for making gasoline engines last long into the future. They aren't making all that much pollution anymore. Most of what we have today is particulates from diesel engines and jet aircraft. Let us not forget coal fired generating plants, which are being phased out.

I'm done.

BTW, wildfires aren't helping air quality either. all that smoke and ash is going to generate rain and snow where I live.

bluejeep2001

Sooo what your saying is i'm trying to reinvent a semi broken wheel...I get it. I will try the larger flex a lite elec fan in the spring/summer next year just because I'm stubborn or stupid. Prob both. Now that the weather has cooled off it barely runs above 185..time for the 195 winter t-stat. Well thanks all for the help and insight

dave1123

I suddenly paid attention and realized you're in the same s***hole state I'm in. Ain't it great? If I could get someone to buy my 1925 house, I'm out of here! If I brought it up to code, the expense would be more than it's worth. I'm still on a well and cesspool.

PatHenry

Just to respond to the earlier "I can't see how a new cap would help".. that is exactly what I would've thought until my own experience. Obviously, just throwing out a thought in the event it might help.

yeah, that just over 210 level is the same as I was getting earlier in the summer - definitely well below the 'blow major components", but any time the needle creeps past the center makes me uncomfortable.

Anyway, sounds like you're ready to do the actual work, so I'm just bloviating here... good luck sir and hope you get it sorted.

bluejeep2001

Thanks...not going to do much now until late spring...came in to work this morning and it was 51 deg..highway driving, no aux fan...didn't get much past the 2nd notch, maybe 170 or 175 tops. My issue is strictly a summer problem. Going to reinstall the 195 so I have some heat and we will start up again next summer..Thanks again

dave1123

About the cap? It's a pressure thing! LOL!