France, I ran my air in Econ mode for the first time and it took to it very well. Air full blast in Econ mode gave me the most stable operating temps that I have had since the heat wave hit us. I'm suspecting that I have an air pocket still floating around that is throwing my temps around and running the Econ mode is allowing more water or air circulation. It needs a good burp or 2. It sat pretty steady at 183 while cruising, then 187 a couple of times due to traffic. Lately it has been more like 185-189-190-194-190-187-185-189 type of deal. I'm going to use Econ mode regularly and try to purge some air and I will update the thread in a few days. FYI it's 100 deg in Dallas, stop and go traffic for commute to work and then some city driving in the evenings when temp is closer to 90 F.

 

Econ also saves fuel , I know it's not such an issue in the US but every little helps particularly with the Rover gas guzzler engine. Good luck with the A/C as heatwaves are stressful wherever.

 

Pretty sure "Econ" is basically vent mode and in "Econ" the compressor is disabled. The only thing the AC would do to the temps is more strain on the engine. It's not going to change how the coolant is flowing thru the engine. If your engine temps rise with the AC on I'd look into the fan clutch or Efan operation.


Just out of curiosity when I changed my 99 D2's thermostat to the OEM grey unit I just drained/filled it, ran it up to 195F let it cool overnight then the next morning I topped it off at the jug and the T. Zero air pockets and I didn't even lift the nose up.

With the OEM setup the temps seem to rise/fall especially with the OEM 180F. With the stock 190F temps didn't seem to rise/fall as much. My 99 D2 is pretty stock (no winch or aftermarket bumper) and it'll do 188F at the 45-60MPH range. When the speeds increase it'll do 193-200F at the 65-80MPH range.

As long as you aren't into the 205F and up range at speed I'd say your fine. At idle my D2's are around 193-200F depending on the ambient temps.

 

My present opinion/take also and would recommend checking out A/C clutch pulley for possibly loading down eng and/or having A/C system checked for proper pressures. Pulley bearings do have a tendency strain an engine prior to seizing and easy to check with belt removed. I see no rise in temps while A/C in auto mode and sometimes deflect vents due to chill factor. Wouldn't advise using Econ in current TX heat unless very healthy and/or have a good life policy.

 

the econ is bringing the temps down. I don't know what is going on with the cooling system. I have tried all types of bleeds and burps but my temps are still all over the place. It hit 189 in traffic this morning. The econ fan was on low. I put it all the way up to high and the temps went from 189 to 181 in 5 seconds. I watched that happen.

 

I think I will have these things checked out as you suggest. I believe there is an issue there, too.

 

im not an idiot (not completely). Im watching the temps in real time as I adjust the speed of the AC blower in Economy mode and coolant temps will change immediately.


Its not the highest temp that I'm concerned with. Its the operating temp spiking up and down when it shouldn't be. a steady temp will hold and then out nowhere, there it goes to 194 like an air pocket is at the thermostat or something. When it did that this morning I pulled over, opened valve on top hose, went back and looked the temp had dropped all the way down to 183 where the stat opens at.

 

With the HVAC in Econ mode, the A/C compressor is disengaged, as is the thermal load it produces on the cooling system by virtue of the condenser being placed in front of the radiator.

If a change in fan speed is effecting a change in coolant temperature readings (and the temperature isn't set to heat the cabin), before continuing, I would validate those reading fluctuations with a laser thermometer reading. It almost sounds like the electrical load from the fan is influencing the temperature signal that the computer is measuring (which isn't an uncommon issue in vehicle electrical systems).

 

When I had a brand new 190F thermostat installed the temp's were much much more stable with maybe a 2F up/down spike. With a 180F the range is more like 6-8F.

We're both in TX Chubb's and I take plenty of trips into Houston, TX on I-10. I'll be cruising with the AC on at 70-75MPH at 193F and I'll glance down at my Scangauge II and the temp will rise from 193, 195, 197, 198, 200F, to 202F and then just as quickly it drops back down to 193F. I have no air pockets, I have no gurgling from the heater core, I have zero coolant loss and this is my 02 Kalahari. Now I have a 99 D2 and besides the winch bumper/winch/skid plate on the Kalahari it's setup exactly the same as the 99 D2. Now that I've gone thru the 99 D2 from top to bottom I've been driving it as well and it will do the same temp rise/fall. Once again zero air pockets, zero coolant loss, no gurgling and it's running a 180F OEM thermostat now.

Interesting enough I tried a $12.00 OEM temp thermostat from Germany on the 99 D2 before I went to the OEM 180F thermostat. It would run all day at 204-206F and in traffic the temp never went above 206F. It was extremely stable with just a 2F up/down temp spike. At idle in park with the AC on it would hit 209F then quickly go down to 204-206F.

I think the cooler thermostat shows the AC temps from the condenser more. I know that when the AC is engaging/disengaging the condenser will heat up and cool down (proper operation) and during my trips on I-10 in both D2's the only thing constantly going on/off is the AC cycling like it's supposed to.

I owned D2's back when they were brand new and I'm 99% sure back then off the factory floor we were running in the 205-215F range. Now we're running 180F thermostats, better fan clutches, and we're in the 188-200F range on 12-17 year old D2's. Some were loved and cherished, and some were run hard and abused.

As long as I monitor my temps and don't see anything rocket over 205F (210F is my absolute max temp) I'm extremely happy with their performance especially here in TX.

 

205, huh. when I see 196 I get really tense in certain places that I won't mention. I let my truck idle with the overflow tank raised, cap off for 1/2 hour and it never got over 175. Then I raised the RPMs for a few mins, closed everything down and I noticed that it stays around the 183 stat opening temp instead of the 187-189 that I've been seeing for the past 2 months. I have definitely affected it, but of course it spiked to 190-something for a while. but when it came down, hovered at the lower 183 like it did before summer hit. I think may need a new radiator now, still more air, or some issue with the AC system be it compressor, condenser, etc.