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What temp thermostat are yall runnin?

B

BIG98XJ

NAXJA Forum User
Location
Duluth, Ga
I wanna step down to something a bit cooler for the summer, and I know the 4.0 is designed to run at a certain temp, so I want some opinions
 
BIG98XJ said:
I wanna step down to something a bit cooler for the summer, and I know the 4.0 is designed to run at a certain temp, so I want some opinions
Click to expand...
Stock t-stat is best: not only is it the right temp but it also has the extra hole :D
 
195

That's what it was designed for. Running a colder thermostat doesn't prevent overheating. If the cooling system is incapable of keeping the temp down to 195, it's certainly incapable of keeping it down to 180.

The function of a thermostat is to keep the temperature UP, not down.
 
Well, I kinda disagree.. just a little. Seemed that when I ran the regular t-stat, It leveled at 210, but it would close & open though, close & open. You could watch the temp go up, then come down to 210, go up, then come down. I think that 210 is high and the engine can cool better than that most of the time, therfore it always closes back off then reopens. When it did close, the temp would climb to like 240 before it would start coming down again. I went to a 180 t-stat and it stays 180 all the time. Granted, it does still climb when it's really hot, but it seems that it allows it to always stay open and therefore do away with all the fluctuation. Ran it half of last summer and all winter now, no ill effects at all. Even watched gas mileage to make sure nothing funny was happening with the computer/fuel mixture.
 
It's simple. 195. Not hotter, not colder. Keep it stock.
 
JKTXJ said:
I think that 210 is high and the engine can cool better than that most of the time, therfore it always closes back off then reopens. When it did close, the temp would climb to like 240 before it would start coming down again. I went to a 180 t-stat and it stays 180 all the time.
Click to expand...

IMO, if it made that much of a difference just changing your thermostat, there's a good chance your 195 was faulty.
 
Well, I kinda disagree.. just a little. Seemed that when I ran the regular t-stat, It leveled at 210, but it would close & open though, close & open. You could watch the temp go up, then come down to 210, go up, then come down. I think that 210 is high and the engine can cool better than that most of the time, therfore it always closes back off then reopens. When it did close, the temp would climb to like 240 before it would start coming down again. I went to a 180 t-stat and it stays 180 all the time. Granted, it does still climb when it's really hot, but it seems that it allows it to always stay open and therefore do away with all the fluctuation. Ran it half of last summer and all winter now, no ill effects at all. Even watched gas mileage to make sure nothing funny was happening with the computer/fuel mixture.
Click to expand...

JKTXJ,

That is what I'm going though right now goes up and down, never had the problem before. I'm going to try another t-stat maybe I got a faulty one, if not I'm going to at 180.

Joe
 
I'd go with the stock 195, IMHO. I can watch my temp in the moring climb past 210, then the t-stat opens and drops down to the area I assume is in the 195 area. It climbs sometimes to 210, but generally not much more.

I agree, keep it at 195, the engine is designed to run at that or in that range. IMHO, theres probably a reason thats the one Jeep decided to use. Plus, like Kejtar said, it has the nifty extra hole that helps bleed the air out of the system when you fill it.

I've been told by one of my mechanic friends that if you go colder, the computer may read the cooler temp and keep it running in, doh, what is it called? Closed loop, or cold loop, something like that. And keeping it in that mode affects your gas mileage cause the computer is trying to get engine warmed to its proper temp. I'm no expert, but from what little I do know, that sounds pretty realistic to me.
 
I tried the cooler temp - 165*?- from Turbo City with no other mods on a trip from L.A. Ca to Abilene Tx, then the stock 195* thermostat fro the return trip. With the cooler unit, power was down and used TWICE as much fuel as I did on the return trip. This past winter my thermostat stuck open and, again, power was down as well as mileage. Guess which gets my vote?
 
The 4.0 was designed to run between 195-210. They are very tough motors. I don't know what or if it has anything to do with it, but, i tried a 185 in mine once, and the motor ran richer and the fumes coming from the exhaust really stunk. Plus,it was like holding back power. I put the 195 back in, and it runs fine. It has 200,000 miles on the original motor.
 
I run a 180. While cruising, with plenty of air flow, it runs at 180. When I get stuck in traffic, the temp starts to climb. But it starts climbing from 180 not 195. This gives me more time to sit through red lights before it gets too hot.

This is only an issue during the summer with the A/C on. I run a GDI 3 core radiator with a high flow thermostat housing and I also use Purple Ice. I don't think it would be an issue if I didn't have a winch blocking part of the grill. I've also got a tranny cooler mounted in front of the condenser. I've got some hood vents off of an old 280Z that I will be installing soon. I am curious to see what difference they will make.
 
I ran the Jet 180* for quite some time. The heep seemed OK and I went with it for some time. I was running the Jacobs ignition, which supercedes some of the computer logic and replaces the coil with a much hotter one.

After I removed the Jacobs, and went back to all stock ignition, the heep seemed sluggish and like it was always cold. I'm back at the 195* thermostat and it is better.

If you're not running a Jet chip or other ignition mods, I'd stick with stock.

bburge
 
Hmm, Im just trying to prevent my jeep of eveer overheating guess I`ll stay with stock, thanks guys
 
I run one of the "evil" 180 degree thermostats in both my MJ and my XJ with absolutely positivlely NO adverse effects. The Cherokee T-stat is going on 20k and the MJ on 5k. Both run noticeably cooler and still get the exact same mileage and no difference in power. You'll hear a whole bunch of conflicting opinions (many from people with no experience using different t-stats in a Jeep) on the issue, but I will not go back to the 195. It just ran too hot for my liking in heavy traffic, towing, and on the long hills of WV. This is not a cure-all that you just throw in and it magically solves your cooling problems, but as a component of a cooling system overhaul, I think a 180 t-stat is a perfectly fine addition.
 
I've noticed now that it's started to "warmup" so to speak, my XJ is getting hotter. When I cruise down the highway, it runs plenty cool, but sitting it climbs up over 210, maybe to the 0 on the 210 mark. After I shut it off and get back in soon after, the temp is way up there, but as soon as I start going, it immediately goes down, which I expected. But when I'm just sitting, the temp keeps climbing and never goes back down until I start moving. Is there something wrong with my T-stat? I'm gonna be going to a GDI soon and a new water pump will be coming this summer and I might just wire a switch to the aux. fan. T-stat problem??
 
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