CSF 3-row cooling a little too well?

here's a thead i thought i'd never start ...

my 98 XJ is running too cold after I installed the csf 3 row.

it was about 25*F outside this morning.
after a 20 minute drive the guage never went past 180*
on a typical 'warm' day it's running the usual 210*

My first reaction was thermostat, although usually the tstat is sticking, not the other way around. I ran a 185* tstat for a short while years ago, but went back to the factory 210* after reading up on it.

Anyone else ever have this issue with the CSFs in cold weather? hell, 25* is not even that cold. i'm afraid to take it up north this weekend.

I'm in Houston, so it never gets that cold here.

It has been "chilly" this week, mid to upper 60's. I have a 180 degree thermostat and a CSF 3 row radiator.

I run about 180 until I get up to highway speeds 70-80 mph for 5 minutes, then I am running at 210ish.

You could always stick some cardboard in front of the radiator on really cold mornings.

The other thing would be to have an electric fan with a bypass switch, so you could just turn it off.

Double check your temp though. Get one of those IR remote units.

Its 25 degrees out, I think thats why its running so cool.

I'm leaning twards the tstat. its supposed to cut the radiator out of the loop when it gets too cold.

no flow through the radiator, no overcooling.

when did you put the 210 in?

was it a good quality brand?

I found that with mine the budget brands don't last very long.

hth

p.s. the IR thermometer is a good idea and they've really come down in $ over the years.

never heard of a 210 thermostat being used in a 4.0

oem thermostat is 195

my 89 is running to cool also and will be replacing the thermostat. if that doesnt fix the problem i will looking into putting a flow valve into the top radiator hose.

89xj said:

never heard of a 210 thermostat being used in a 4.0

oem thermostat is 195

my 89 is running to cool also and will be replacing the thermostat. if that doesnt fix the problem i will looking into putting a flow valve into the top radiator hose.

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you're right, it's 195. i dont know why i said 210.

anyway, it's still running too cold in my opinion.
never in the 10 years i've owned this thing did it go this low on the stock radiator and i've taken it up to Maine when it was -30 out.

the tstat came from autozone and has a few years on it, could be suspect. that's an easy swap.

(lets see how long it takes before some Maineiac replies with "-30, ha! we call that warm!")

lol, yes change the tstate before any of that other stuff I said!

Im with Mudderoy, 180 on the guage could be 200 at the thermostat. I did an engine swap with a 98 in my 89. had to relocate the Temp sending unit. it always shows about 10degrees cooler that it is actually running

change the thermo, or check it on the stove. But if it is good, your other option would be to cut a round piece of hdpe plastic (some cutting boards are made of it) that is just big enough to fit into the upper rad hose, but too big to fit into the radiator. Fit it up against the rad, then slide the hose on. Drill a hole in the center of it, start with about 1/2in and work up till you get to a hole size that will keep the motor warm without overheating. I think that I remember a 9/16th in hole being about right in a lot of northern places. It will restrict the fluid flow a bit letting it get hotter in the motor.


I need one of those nifty IR guns, just because

mine does the same thing when it is cold. i have the stock radiator.

rufus_1111 said:

mine does the same thing when it is cold. i have the stock radiator.

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But is it new? I have had the same problems since I installed a new 2 core. I know my T-stat is working because the temp. gauge moves when it opens & closes. I also checked it on the stove. I just block part of the rad. with cardboard. Helps with warm ups & keeps the gauge just a tick below 200. JIM.

I run a CSF 3 core with an OEM thermostat and haven't overcooled, although I was on the highway last year when it was about 10 degrees out and my heat wasn't all that good.

So far this year my heat seems better than ever, perhaps it is possible that the system has bled itself even further of air than last year? Heat seems alot better for sure compared to in the past.

I do need to build a shroud for my radiator though to close the gaps between my electric fans.

Either way my system is running just below 210 in this weather and the electric fans aren't even on unless it idles for prolonged periods.

Stand and OEM Jeep thermostats have served me well.

I ran one autozone once, it worked alright, but then i ran another autozone thermostat and my heat sucked terribly! This was awhile ago though, not recent.