Well my old radiator was fubared, and right after I did intake/header swap I figured I would change out radiator, as my stock one was missing over half the fins and leaking. Went to junkyard to get a replacement, and found a brand new looking 3 row (I am assumming it is a 3 row is it is over twice as tick as stock, and looks a lot like the 3 row replacement I bought from o'reilly auto that didn't fit right. So now I am driving it today, and if I let it sit and idle for a few minutes it will get to about 210, but when cruising (its over 90, a/c so electric fan isn't on) and it is just barely over second hash mark, like there are five marks, first being 100, middle being 210, and last being 260, and it is barely over the one between 100 and 210. Aren't these supposed to run like 210, and if so, is it like newer vehicles were it has to get to a certain temp to run certain timing perimeters and such not? I have a 195 thermostat or whatever stock replacement is, and I am just concerned as if it does have to warm up to get certain operating perimeters concerning fuel and timing it might not be reaching that temp and if it is running this cold now what's it going to be like in the winter.

 

if you have the 195 tstat in there you will be fine,the motor has to come up to that before it opens

 

I have a 180* t stat and mine runs at 180* while driving and at lights and traffic it is about 200ish with the a/c on.

 

Thats not something you hear too often.

 

Its not that I am worried about the actual temp, I am more worried that the computer will stay in a "warm up mode" like some vehicles do if they don't reach the correct operating temperature.

 

So am I just being ignored or do you guys know anything technical about the 4 liter.

 

Like I said mine runs just about the same when not running my a/c. I have nt had any problems. If you want put in a 180* t stat and see if that helps any.

 

I don't think 180 degree t stat will make it run hotter, will it? My biggest question is the ecu in a warm up mode until it reaches correct operating temp?

 

Well if you want to run hotter put in a 160* t stat and it will be open alot more. You said your a/c is on. Well with the a/c on your 2nd fan should be on

 

when i said "a/c so electric fan isn't on" I meant a/c wasn't on. and if you read the question I don't want it to run hotter if it doesn't have to, I just want to know if the 4 liter has to reach a certain operating temp to run correct fuel/timing tables like a lot of other vehicles, it is a simple question.

 

Yes, it should run at designed temp, no this it isn't a HUGE deal if your vehicle runs cooler than expected however I would be concerned about a couple of possibilities. First, bad tstat is causing it to run cool, in the summer not too big of a deal but your engine will not run as efficiently and could cause problems later. For sh_ts and grins I suggest you change the tstat.

The second possibility is you have a large air pocket under the tstat that is not allowing hot water to reach it. This will cause you to overheat and not even know it.

change the tstat

1. park your jeep nose up on a slight incline.

2. remove the tstat housing (visibly verify that there is actually water under the tstat, if there is no water then you had an air pocket.)

3. install the new stat, fill the radiator with a 50/50 mix and, leave the radiator cap off (if there was an air pocket go ahead and add the 50/50 mix of coolant and water, be careful not to flush crud into the block).

4. start the engine and run it until the tstat opens, verify you have flow and, top it off and cap it, check your over flow reseviour, make sure it is filled to the hot line and double check the condition of your overflow hose.

Never add cold water to a hot engine unless it is running with water visible and flowing through the radiator, add it very slowly (trickle) so you do not "chill shock" the engine block or head.

 

thermostat is good and functioning properly, maybe the radiator is just to efficient

 

Going by the 3 row rad specs at Radiator Barn, a 3 row is only 3/4" thicker than a stock 1 row.....far from twice as thick. I think your gauge is wacked. The XJ rad is really dinky size wise, 3 row or not, and in 90F+ ambient temps running a/c, coolant temps below 200F just ain't a happening thing. I'm talking about actual coolant temps, not what the factory idiot gauge displays.

 

You are probably right, I think I went with autozone coolant temp sensor instead of mopar anyways so maybe that's just what is off. Just the thing is, when the temp reads around 210 like if I have been sitting still for a while the jeep is noticeably more peppy like it has a better air to fuel ratio or more timing or something, guess is doesn't matter to much though, a little on the cold side (if it is) is a lot better than overheating.