I thought I had the cooling system fixed

I have a 96 4.0 auto. Since I got it I have changed the belt, fan clutch (Noisy HD napa one), hoses, t-stat, temp sensor, cap and flushed the system. The radiator (stock style) was changed about a year before I got it. Everything is working as it should and in normal traffic and ambient temp (up to 85) it has been dancing around the 210. Yesterday while coming home from a long trip I got stuck in traffic on the FDR in NYC, amient temp was 100+, within 20 minutes of sitting in traffic my needle was just a little past the halfway mark between 210 and 3/4. It's never gotten this hot with the AC (aux fan) on so I jumped off the expressway and took surface streets and she cooled down.

I didnt know how much higher she was going to climb but with my wife and daughter in the jeep, in the middle of Harlem I didn't want to find out.

Has anyone had similar experiences, how high should I let it climb with the aux fan on before I need to start worrying.

After you did all that, did you burp the system?

I did.

Some times you just have to replace the radiator, they do go bad and the cooling fins just don't transfer heat anymore.

Open system (96) really is self-burping. It can require a bit of assistance after a complete drain and refill, but will usually self-burp after a couple of heat/cool cycles. Except for the really bad designs where too much of the cooling system is higher than the physical radiator.

There are limits to a cooling system. 100+ temp, humidity, idling, a/c on--that is asking a lot of any system.

I would examine the radiator to see if it is a single-core, and if it is, consider upgrading to a 2 or 3 core.

Check your coolant mix:

"The standard recommendation is to use a 50/50 mix of antifreeze and water. This represents a compromise between cooling efficiency and the ability to prevent the mix from freezing during cold weather. After all, the initial purpose of antifreeze is to prevent freezing.
But a 50/50 mix does not give the best cooling. For improved cooling in hot weather, we should use less antifreeze and more water, perhaps going to a 25/75 or a 20/80 mix ratio.
Everyone knows antifreeze prevents corrosion, and corrosion is bad. True enough. But, even a 10/90 ratio of antifreeze to water will serve the puproses of inhibiting corrosion, at least according to one source of information"

From: http://www.challengers101.com/CoolantMix.html

I have a single core radiator and I'm running a 50/50 mix with Water Wetter, but I think I've hit the limits of the systems as is. I think Im going to have to bite the bullet and get a 2 core and change the water pump while I'm at it. Who sells a good 2 or 3 core at a good price?

I've never had it overheat but I get nervous seeing the needle move toward 3/4.

DPG Offroad has the CSF 3-core for a good price, they are supporters, and if you were a RED member they offer a discount: http://www.dpgoff-road.com/site/radiators.htm

Any problem with these radiators and the HD fan clutch conversions.

3 row with ZJ HD clutch fits fine in the Renix-- don't think there's any change in spacing between any of them, though.

+100* and sitting in traffic today-- right at 200* without AC/ cooling fan running (doorless)

I save the AC/cooling fan for hot weather, if needed.

DPG does mention on their website that the HD fan will work as long as it isn't made any deeper than the stock fan clutch. My NAPA ZJ HD fan clutch was exactly the same depth as my stock OEM fan clutch.

joe_peters said:

DPG does mention on their website that the HD fan will work as long as it isn't made any deeper than the stock fan clutch. My NAPA ZJ HD fan clutch was exactly the same depth as my stock OEM fan clutch.

Click to expand...

x2 The ZJ clutch is bigger in diameter but not width.