NICE! That is great performance in those conditions. I assume you had the AC running full blast in those temps?

 

No AC. Didn’t want to push it.

 

Oh man, that's rough. "It's a dry heat though" LOL

 

I use the OEM 180 stat and it works well, but I'll probably consider upgrading to the inline mod next spring because my AC condenser fan is still seized. I bought mine from Lucky8 and it works great.

Temps are 188 on the freeway in any conditions, 188-194 around town. If I'm idling for extended periods in hot (90+) weather with the AC running, then the temps start to creep up, though. Without the AC it'll never go above 194. This is in combination with the 2991 clutch and 620-112 fan.

From what I can tell, if you're going to go and make changes, just go straight the inline mod, since I do think that some people get unlucky with the 180 stats, and the inline mod will definitely keep you a little cooler.

 

@boston4 I run the exact same setup. Lucky8 OEM 180, Hayden Heavy Duty + Doorman fan. Temps are the exact same as yours. 188 or less above 60mph, and no more than 194 in town.

Hot idle I sometimes get 197, but it comes right back down to 194.

I recently fixed my A/C fan and it keeps things nice and cool with the A/C on. With those temps being so good I have not been motivated to switch to the inline mod, but I've hard a lot of these horror stories about OEM 180's failing...

 

A little more info on thermostats -from todays drive

Black Td5 Thermostat, Hayden HD, Dorman Fan
82 -85 F outside temp
No heat or air

30 to 55 Mph on the flats 188 -190
60 and above 194
Long idles in park 194, 197 in drive after a while at long lights

Long steep climbs off road at low speed 1 and second gear low range CDL engaged 206 max speedo not registering too slow
Long steep climbs off road at low speed 1 and second gear high range 210- 212 max 5 -10 mph

After those climbs if there is a long downhill temp drops to 183- 177 inside of 2 minutes
If there is a long flat 185-188 after about 5 minutes at about 20 mph

Inline is going in in the next few days - but temps are as expected other than the 210-212 should dropped the CDL in it was a ugly uphill lots of bouncing and traction control


Start of the long up-hill in 1/2 low range it gets steeper and rougher for a bit

 

So I have the inline stat as well, 180 thermostat. I have been chasing some 210-ish uphill temps 100 degree heat. (they were near 230 with the old fan clutch and grill). What fan clutch do you have? I just swapped to the Hayden 2991 and I didn't really notice any increase in sound or decrease in temps. Isn't that supposed to be the most severe duty one for the discovery 2?

 

@Jason_B The 2991 is the severe duty, the only time I hear my fan is on startup. The engine insulation appears pretty much block it otherwise.

In my case the temps are only high in very specific conditions, very low speed, high engine load, high ambient temps. Pretty much an expected outcome, the cooling system cannot overcome the heat being generated. But 212 is well with in the safe range, given the rapid drop after the load is removed or once I get moving and better air flow I do not believe there is any major issue.