nc527

So after fixing my ac a few weeks ago, my Rad blew the next day(because I forgot to put the hard line clamps back on the ac lines). So I ordered the 3row all metal radiator from radiator barn, and installed it last night. Also installed a new thermostat, and rad hoses. Now with the e-fan off, going 55 down the road the temp is staying at 210. When I stop, it goes up halfway into the red, around 240-250, even when I turn the e-fan on. We popped the hood, and used a digital thermometer to measure the temp right at the thermostat housing, and it read 210, while the gauge inside read 250.

Do you guys think the temp sensor is bad now, or the gauge, or what?

Also, my mechanical fan has no cowling around it. Does the cowling have a big effect on the cooling capabilitys of the fan? should I replace it?

kennzz05

its cheap enough why not
http://www.partsgeek.com/catalog/198...an_shroud.html

ZINGGG

Yes you should put in a fan shroud.

Sounds like the sensor at the rear driver's side of the head took a crap. There might be a small difference in the temperature of the coolant in the thermostat housing and at the rear of the block but I wouldn't think 40 degrees. A few degrees, maybe. But I wouldn't think that big a difference.

I may be wrong though.

Devodale

That's still way too hot. I did the exact repair, using a 160degree thermostat and same 3 row radiator (CSP), and I'm running at 170degrees going 65mph, and at idle it might reach 220degrees on a hot day. Are you sure you burped the system and added the full amount of fluid it can take?
I filled mine to capacity before starting the 1st time. Then I waited, with the radiator cap off, until the thermostat opened, depending on which one you bought, I assume a 180 degree, the level in the radiator dropped immediately...my gauge read 160 at that time, making my gauge correct. then completed filling it as needed until it would not take more.....took maybe 10-15 minutes
Definitely get a fan cowling, but if its not a senser (Very possible) it sounds like a head gasket to me....white smoke from the tailpipe at all? Or constant bubbles coming with the rad cap off?

CPTslackass

210 isn't too hot for a 4.0l. Infact, that's perfect. Running at 170 will cause your 4.0l to stay in open loop. Causing a rich running condition. Overtime, you'll carbon up that motor.

Oem stat is 195. Stay with that.

ZINGGG

Yeah... 170 is way too cool..........

Roler

(Over)heating when you stop but not when driving: fan clutch still good?
Heater warm, so waterpump good?
(Just a few other things to check to make sure)

nc527

We followed the procedure in the haynes manual for checking the water pump(pinch the top hose shut, and feel for a surge of coolant when you let go), and it seems to be working.

As far as the fan clutch goes, I think its good, any ways to test it?

Devodale

Hmmm, thanks.
I live right on the coast here, but frequent inland to crawl alot where it's much hotter. I wanted to run cooler while wheeling...but wasn't aware of any consequences....thx again.

djb383

170 coolant temp WILL NOT make the system remain in "open loop". The O2 sensor is what "closes" the loop. Coolant temp below 160 for too long will set a CEL.

CPTslackass

Interesting. I was always told that keeping the system cool like that wasn't good and kept the system in open. Learn something new everyday!

Even in the Kansas heat, I still run a 195 and have had no issues at all. Ac on. I like to stay OEM how ever.