Can you be to cool ?

I am considering a number of diferent cooling system upgrades. What I am wondering is can you get a 4.0 HO too cool? I would still like to have heater during the winter. I have looked at 3 core rad.s, highflow pumps, electric fans and ect. Anybody have any experience with these mods. I do already run a high flow water neck, hood vents, and a Jet chip. I just want to be cooler. :smoker:

I've never seen an over-cooled 4.0, at least in my neck of the woods. If you can get it cooled to 195, the thermostat will close, and it'll heat back up again......

CRASH

Have a closed loop system on my 88'. 3row rad. T-City T-stat housing, 195 degree t-stat (switched from 180 Jet T-stat). Runs great on the highway and around town. I do a lot of driving, but have never over heated with it. This things like to run a little hot. Hotter than most other cars/trucks. Emissions and mpg thing is what I have been told. I did notice that my mpg has improved with the 195 verse the 180. So I guess that part is right.
Juice

I have an 87 with a 3 row. I saw a dramatic increase in gas milage when I went from the 160* t-stat to the 195* engine runs better too.

Neil

Yes my thought was you can't over cool an engine, but I have heard rumors that this was not true for the 4.0.
assgas:

You can't really over cool it but you can *run* too cool. One of the problems I remember reading about the XJ was the design team was a bit miffed at the limited amount of space they had for the rad hence the funky radiators they use in them with those stupid dog leg filler pipes. I was all set to order a modine but I think I'm going to order one of those 'be cool' alum rads instead, need to read a bit more to justify the cost to ME before I fork over the extra money.
As far as maintaining temp, thats what the thermostat is for. The increase cooling capablities of the rad only come into play when off roading or traffic, thats when a good rad comes into it's own...

Rich,

Well put. You never know how well it works until your crawling on the highway or offroad in the high 90's temp range. That always lets the cat out of the rad. LOL. Juice

You guys might be interested in this guys water pumps then. I am thinking they look like a good idea. http://www.flowkooler.com/

Yes, it's not hard at all to over cool a 4.0. All you need is a good radiator and a too cold/bad thermostat. My '90 would barely get above 160 until I replaced the thermostat. If you have a good 195 degree t-stat (like you should have!) no, it won't be too cool.

Keeping the oil cool is another way of managing temperature. After you set up the cooling system the way you like, move the oil filter behind the bumper (and away from the engine) with a relocation kit. Also easier to change the filter.

Just another option for you.

Joe V.