Those temps sound comparable to when I was running a stock bumper and 265/65/18s. I rarely saw over 205 on long grades and climbs at altitude. I changed quite a lot since then which is why I think I need some extra capacity in the rad to cope with the extra weight and reduced airflow.

 

Those temps are safe in my opinion, but I’m with you and would raise an eyebrow.

A couple anecdotes:
- Although I think the Extinct solution absolutely rocks and is a wonderful solution for MANY reasons aside from aiding in cooling, I don’t think it’s entirely necessary due to the below…
- On the freeway at 75 mph I’m running 186-194 and this can be up to ambient temps of 90F+. I’m also at 6500-7400 feet in elevation.
- With the AC on, I’m going to COMPLETELY contradict what I’ve been saying for years and say the condenser fan actually DOES help with cooling because when I get off a freeway stint and have had a good load on the engine, temps will drop to 179 or even lower as it has a chance to take a break. Also, it will start to hover at 190F with ambient temps in the 70s and even 80F with the AC off.

The equipment I’m running are as follows:
- I’m at 172k miles and this is a 4.6 SAI engine
- OEM soft spring 180 t stat
- new Nissens radiator
- original (since I bought it) water pump (but have a Flowkooler on the shelf just in case) and everything else is left alone (expansion tank, hoses, etc)
- Prestone green stuff 50/50
- Splash of Water Wetter
- new fan
- slightly more grumpy (but not extreme) clutch

I’m still finishing shaking down my latest D2, but I’ve got enough miles on it now to know it’s characteristics. Based on the above, I’m calling my cooling system done until a component fails or it’s time to flush again.

 

Quick update here. I’ve been inspecting my fan clutch throughout the past several months. I decided it needed changing about the time I started this thread.

Got around to installing a Hayden heavy duty clutch and dorman fan on Friday. I haven’t put in any interstate miles, but so far temps are down 5 degrees across the board. Running much more in line with what I’d hope for.

Going to add some water wetter in a few weeks after getting a good idea of how much the fan clutch helped.

 

Same thought process here... I am currently using a Hayden 2781... awaiting the arrival of the 2991 severe duty from Amazon on Wed. Will also share my data when I make the change.

 

+2 from me on the Flowkooler water pump. With the combination of the inline mod and the flowkooler, I can't get mine to go above 183

 

Jackpot! Temps went dwon significantly when I changed from the Hayden 2781 standard duty to the 2991 severe duty.

- Turner 4.6 (3 years old)
- Factory water pump (installed with the Turner engine)
- Nissen radiator (few weeks old)
- Idler, pulley, belt (one year old)
- Pentosin Pentofrost SF
- Extinct Inline thermostat

When I had the Hayden 2781, and even with a new Nissens radiator, I was seeing up to 215-deg F when going up gradients.

Now, with the Hayden 2991 @ 82-deg ambient and air-con turned on..... I am seeing 174 to 188-deg highway, 194-deg climbing. It did go up to 206-deg when I climbed to a top of a mountain and idled for a couple of mins, then started dropping quickly.

Next steps, I am going to clean the crud off the a/c condenser fan and cooler. I have also a FlowKooler pump that I have not installed yet.

 

Quick update here - I did install a heavy duty Hayden fan clutch and Dorman fan.

That certainly changed the behavior of my temps around town and lowered them by 3-5 degrees or so. But as expected Highway/ interstate temp still runs about the same, maybe marginally cooler than before. So still a little hot for my liking.

Without the AC on (unbearable in the summer obviously…) the coolant temp almost always stays around 100 degrees hotter than ambient temp at Highway speeds. With the AC on it seems to stabilize about 15 degrees over ambient.

Ive got the extinct 180 incline mod, recent coolant flush with BMW blue coolant, new Nissens rad, all other cooling systems parts are less than 2 years old. AB long block with roughly 30k miles on it.

I did have a brush guard but removed that thinking it was obstructing the grill at speed, that made almost no difference. Temps are the same when testing without thermostat.

Since I’m still running sub 200 degrees most of the time it’s not really a worry, more of a curiosity at this point.

I don’t have documentation that the motor in the car is in fact an AB long block, it’s possible it was a short block and could have the water pump from the original motor. Based on what I’m seeing that’s the only thing left to address.

I was towing a 3,500lb load in 95 degree heat, and as long as I toggled the AC from Econ to regular mode I could keep the temps right around 200 degrees.

Any further ideas? I added some water wetter yesterday - no noticeable changes in temps (I didn’t expect any).

 

I WISH the highest temp in TX was 203F... In a D1 I see anywhere from 188-220F (range year round on road/off road) 180F, HD clutch new radiator, and both efans working. D2 wise with or without inline mod the range is 183-215F for same conditions.

The coolest D2 I have is my 99 D2 with a HD fan clutch, grey 180F LR OEM thermostat, new radiator and it's 184-206F. 02 Kalahari with inline is 178-215, and the 04 with a grey 180F OEM LR thermostat, new radiator is 188-206F. D2's have slightly different front bumper/recovery gear configs, but it's just the concrete jungle temps, off road down in a creek with no airflow, sitting in traffic, or in a drive thru...

5 LR's all very similar range so the only common denominator = environment. These trucks can handle up to 229F but of coarse it all depends on the condition of the LR. Cooler is always better but in an extreme condition your LR should not blow up at 229F. Back when the D2 was new and no one had OBD2 Bluetooth readers I can guarantee the temps were 205-225F off the assembly line.

 

Coming home from the lake today, 00 D2, winch bumper with winch. 265 18's, inline mod. 230k on the motor. 70mph, looked up an obd reader said 194, pressed the hvac exterior temp - 93. How many radiators have you tried?

 

Maybe it's just the recent Nissens but both the ones I tried don't run as cool as the LR rad they replaced. I'm on the waitlist for a Alisport rad but that isn't exactly an apples to apples comparison to a stock style rad. Either way, I'll be installing that along with a flowcooler eventually.

Fwiw, I run at 188F at 70 MPH in temps up to 85ish ambient with 33" km3s, winch bumper, winch, lights, along with an RTT. I have a new Nissens rad, Hayden HD fan clutch with dorman fan, with the 180F inline tstat. I need to try doing the mesh grill mod as well to see if that helps temps.