Hey all, so I bought a 1996 XJ probably about 2 weeks and I can’t figure out why it’s keeps over heating! It has the 4.0 and auto trans with 4x4 and has about 220k on the clock.

When I bought it, it was running around 210 but at idle it would go up a little and I didnt like that in this heat so this past week I replaced the radiator with an almost OE one (I know this ain’t my first 4.0 I know how shot they are but it’s for the time being and it’s not a daily), 180 degree stant tstat, waterpump, waterpump inlet hose, both upper and lower hoses, and the fan clutch. Now it runs around 210 but I can’t sit at a stoplight without it going over 210 and I’ll have to turn the heat on. I don’t believe the oil is milky, I used to distilled water with the new rad, it doesn’t smoke.
any help would be appreciated becuase I’m at a loss😂
also the heat works great and my windows aren’t fogging up and there isn’t any wet spots in the carpet so I know my heater core is alright for now

 

So are you sure its even overheating ?... It also has a secondary electric cooling fan, which comes on with A/C..or when temp reaches 105C = (221F)

Your XJ is not overheating if the fan comes on at idle (221F), and the temperature drops to below 212F, then cycling on-off

If the electric fan does not come on, or the temp starts to run toward the the redline, then you have a problem.

running down the highway, with the motor fully warmed up, my OBD2 scanner and gauge indicate running temps at 88-91C..within 1 minute of idle, temp will be 100C+

 

50/50 coolant I hope?

 

Yes it has the ****ty looking plastic E fan on the driver side and I wanna say it works but it’s almost not enough, I’m not sure if the gauge is reliable, I plan on putting a heat gun to the tstat housing tommorow to see but at idle the temp gauge starts to slowly climb towards the red line but when going down the road it’ll stay at about 210 or so.

 

Yes😂 I always run the stuff that you have to dilute yourself on a brand new rad.

 

it is or it isnt..if the car can sit at idle on a hot day, and that fans cylcles on and off, the vehicle is operating as per design, and not overheating (engine temp will be between 210-222F

if the fan remains on for more than few minutes, and doesnt cycle off, the temp will climb up to the redline quite rapidly

presumably both fans have the shroud intact ?

prolonged idle in 90F+ ambient is how I test all my vehicles cooling capacity, that and a flat out run up & back a big hill near to me

typically, turning on the heater with fan full blast, if that brings the temp down from near redline, means something in the cooling system is bad

As you have a '96, may I recommend, as per Jordan96, the BAFX OBD2 scanner, about $30, tells al lot, including coolant temp ( I have one)

 

I’ll have to to get me one of those scanners and tommorow I’ll run that ambient test and be sure to watch my E fan, I’m pretty positive it works but I’m not sure if it cycles off haha, but I’ll definitely let you know what happens.

What do you think would be bad if there is something wrong? I’m just tryna wrap my head around what else could be going out, like I said, the majority of the system is brand new and I know the OE style rads aren’t the greatest but I’d imagine it’s so better than this.