• DCRC 2024

Do 4.0 TJs run hot?

shrubeck

shrubeck

Mmm Commulicious
Location
Grand Junction
I have had many XJ in my time and have had many over heating problems. I'm thinking about getting into a TJ sometime in the hopefully near future and I'm wondering if I should look for a 4.0 or a 2.5. I would like the power of the 4.0, but I can live with a 2.5 if it means no more overheating problems. So what I'm wondering is do the 4.0 TJs have the same f#@*ing overheating problems the 4.0 XJs do?
 
RockMonkey

RockMonkey

Suddenly Enthusiastic
I think the overheating thing is an XJ problem. YJ 4.0s seem to have great cooling systems, and so do TJs. The radiator in my 2.5 TJ is kinda crappy. FWIW, I run a 4.0 in my buggy, and have zero cooling problems (even in 117 degree heat) with a Griffin radiator and Taurus fan. It's not the motor that causes the overheating problems, it's the XJ. ;)
 
K

kyojin

Registered User
Location
Herriman
I have had zero problems with my 97 TJ 4.0 overheating. In 100+ temps it always runs at 210 degrees. I would recommend getting the 4.0.
 
Badcop

Badcop

Who Dat? Who Der?
Location
Hyrum UT
RockMonkey said:
I think the overheating thing is an XJ problem. YJ 4.0s seem to have great cooling systems, and so do TJs. The radiator in my 2.5 TJ is kinda crappy. FWIW, I run a 4.0 in my buggy, and have zero cooling problems (even in 117 degree heat) with a Griffin radiator and Taurus fan. It's not the motor that causes the overheating problems, it's the XJ. ;)
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I agree, its a square headlight thing, most dont understand. My old 02' TJ 4.0 was awsome with cooling even with the winch and lights in the way of the grill.
 
Badcop

Badcop

Who Dat? Who Der?
Location
Hyrum UT
Brett said:
hmm....never had a problem with any of my XJ's with cooling. Maybe do some maintenance on your Jeep now and then and it wouldn't have problems.
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Since Ive owned about 20 of them Ill argue this fact.

84-86's 2.8l, hmm enough said.

87-90's the closed core 4.0 has a nefarious way of overheating for any number of reasons, sun is in its eyes, the wind isnt strong enough, etc. The closed core is a PITA and is a really worthless setup.

91-94's first years of the HO, some still had a closed set up (refer above) some with the newer open core had little problems.

95+' first year of the "S" blade electric and open core, problems solved.
 
MOODY

MOODY

Bald Guy
Location
Sandy
If you are REALLY concerned about it, kill the issue up front by installing a hi-flow thermostat housing, lower temp. thermostat, upgrade the radiator, fan, and flush the system yearly. I have done all that, plus I run a 60/40 (Coolant/H2O) mix and I haven't ever run hot ( I own an XJ). It seems like there is more airflow through the TJ engine bay than the XJ too, so you are already ahead. A small sidenote, at EJS this year, I spoke with a guy who was from Arizona, and he had the 4.0, but, was running 39" tires, a supercharger, etc. etc. on the stock setup and made it a point to tell us that. He was proud he didn't need to upgrade, even in AZ. Neato.
 
shrubeck

shrubeck

Mmm Commulicious
Location
Grand Junction
Brett said:
hmm....never had a problem with any of my XJ's with cooling. Maybe do some maintenance on your Jeep now and then and it wouldn't have problems.
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WOW, thanks Brett why didn't I think of that :rolleyes: . As soon as I got my latest 87 XJ, I replaced evertyhing to do with the cooling it including switching it to an open system, and it stays plenty cool. I know how to make an XJ run cool, it's just a pain in the ass. The point is I plan on getting a TJ and I don't want to have to fight the same battle yet again.
 
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Milner

Milner

formerly "rckcrlr"
Location
Hiding behind a camera
The long, short shape of the XJ radiator is the biggest part of the problem....I was reading some stuff about radiator design, and this shape was said to be the least effecient. Angie' XJ overheated constantly until I installed a 3 core open system radiator. It has been fine since then.
 
mbryson

mbryson

.......a few dollars more
Supporting Member
Location
Bountiful, land of rocks
My '91 XJ ran about where the thermostat governed it. It had a 195 thermostat and even on the hottest days, it'd sit around 205/210ish (seems like the gauge wasn't real accurate if I remember right?).
 
ewander

ewander

Registered User
Location
Lehi, UT
I moved to a 3 core radiator and still run 215.....which according to all the experts on NAXJA it is fine.....

Neither of my bro's TJ's ever run hot. In my opinion XJs kind of suck, so good on you for getting a TJ. I wish I had kept my YJ.
 
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