So I just put in a CSF 3-row, Flowkooler water pump and a 180 degree tstat.

I now run a steady 200-204 degrees. Previously with the old setup I ran a steady 190-195 degrees.

Anyone have any ideas as to why this might be? Only thing I can think of is my old tstat was shot and "always open". I'm pretty confident it isn't an air pocket because the temp is steady and usually when the system needs to be bled the temp will fluctuate.

It hasn't been as hot since I put it in as it was previously so I know that isn't the case.

seems to be a common problem when going to a the csf 3 core.

i've taken mine back out after chasing the same problem and went back to a stock type single core, along with many others that had the same problem after installing the csf 3-core.

for some they seem to work...but i know of 7 that have been replace by radiator barn with a wide single core and a refund for the
difference.

they (csf 3-core) did run cooler on the trails or at low speeds (under 40) but didn't cool worth a crap at highway speeds with a/c.

Before going to all the work of pulling that radiator, try putting a 195* thermo in it. That's the temp. rating that came from the factory, and the theory is that if it opens too soon, the coolant doesn't stay in the engine long enough to absorb enough heat to make the difference.

Sounds counterintuitive, but do a search on "195 thermostat" to see where I'm coming from.

Keep in mind the jeep 4.0 was designed to run at 205* and most ppl think this is a problem... it ISNT. As long as you dont have any leaks.. and you have gotten all the air out.. you should be fine.

I don't doubt your experience but when I researched cooling systems before I bought I never ran across anything like that in regard to the CSF - and there is a LOT of info out there on it.

I would love to see a discussion on WHY a 3-core wouldn't cool as well as a single core.

It isn't a problem under normal driving but if you start stressing it you have zero margin for error.

When my old system was running at 190* it would work up to 210 when wheeling on hot days. If I turned on the AC it was sketchy.

That is what I was trying to avoid with this upgrade.

You also need to look at the fact that the cooling system in an XJ BY DESIGN was inadequate - as were the brakes. Simply because it was designed that way doesn't make it good.

I switched to a 3 row radiator from radiatorbarn. Couldn't be happier. All speeds, idle, and highway was improved greatly. It never goes above 210 unless I'm hammering it off road on a super hot day....temps near or over 100 degrees outside. Right now its in the 80s and the highs close to 90 degrees and it won't touch 210. Even idling for a long period of time. I have ZERO problems or worries with my 3 row rad from radiator barn.

MY rig is strictly a trail rig... I have only done two things to it.. 1 was to upgrade to a 96 radiator... and put my e fan on a switch. My rig runs just fine on the trail. I have never had it overheat.. and believe you me.. I put a lot of pressure on my rig on the trail.

if the csf 3-core cools so good then why can't it maintain a 200* temp regardless of what thermostat is used or if the a/c is on or not? providing that the rest of the cooling system is in good workig order.

the radiator is supposed to cool the coolant, the fans are to provide air flow to allow the radiator to do its job, the thermostat is used to get the engine up to minimum temp quicker and to maintain minimum coolant temp set by that thermostat, it don't matter if it's a 180* or a 195 that's just the mimimum temp. the engine or pcm/ecm don't care if it's 180* or 195*.

those of you that think the xj was designed to run @ 205*-210* don't know the engineer or anyone in the design team so just what is it you know about what temp it was designed to run…nothing more than it came with a 195* theremostat, has a fan clutch, an electric fan that comes on @ 218* or when the a/c is on and 260* is too hot. some of you may even have counted the blades on the fans, but most don't know how many are on which. by your thinking it would seem to me that the xj was designed to run at an operating temp of 195*-259*.

i bought csf 3-core because i didn't want a running hot issue due to the ability of the radiator to exchange the heat. well it didn't work for me, or quite a few others.

i'm sure if one were to google, the same threads i found regarding this issue would still be found.

aluminum vs brass/copper thermal efficacy seems to be a big part of this problem. then throw in that they are all about the same thickness but the tubes are smaller in a 2 or 3-core compaired to a 1 core. again thermal efficancy come into play. then you can throw in more cooling fins and get into...more thermal efficancy and air flow issues. thermal dynamics at work.

like i said it seems to work for some...but i know of more that had problems with it in their daily driver than it worked for.

if it works for you, hey good for you.

Had the same results as iken, had a broken plastic tank on my stock radiator. Decided to "upgrade" to csf 2 row brass/copper and had highway over heat issues and spent weeks changing parts and then went back to radiator barn for a stocker and fixed.

The csf works awesome for low speed low rpm, but highway no so much.