sometimes my truck won't do this for months at a time, though. that's what gets me. I will have to break back into the cooling system to install this new flexible upper-radiator hose and adapters to clean up the inline mod and was looking at ways to vaccum-fill it. There's no way, as the "top-shelf" products pull so much bar that it will suck the radiator seals/gaskets inside the tank and cause leaks, so I'm not going there. I really want to see if a new radiator will level out the temps but as of the moment, its not worth $200. I am sinking a ton of money into cosmetics right now. so long as temps stay right where they are, Im not going to touch it. ever hits 200 F, new radiator.

 

Running our rigs cooler is a great idea and we're all doing that with 180F thermostats, and a well maintained cooling system. But honestly everyone is WAY to sensitive on engine temps IMHO. I've got an 08 Hummer H3 with an all aluminum 5.3L LS3 V8 and like the LR V8 and D1/D2 body style the grill area is rather small and so is the radiator. Before I modified my H3 the normal temp range during the summer with the AC on was 210-220F..... After I finally figured out the proper way of modifying it with a D2 efan puller fan setup (H3 had no efan at all just the fan clutch/fan blade) the temp range is 193-210F. Heck I had it up to 237F between Houston & San Antonio (due to a crappy $$$ complete Efan setup), and that was nearly two years ago now with zero issues.

With that being said and me being around Land Rover's from the early 90's, the arrival of the D90/110, the D1, the P38 RR and the D2 they were shipped and designed around a 190F thermostat and those temps are going to be 200-215F without even factoring in the heat/humidity that we have in TX. Realistically a 180F thermostat should be in the range of 190-205F. Trying to keep it running cooler than 190-205F is going to require a lower temp thermostat. That's why I'm completely happy with 205F as a max temp and the 180F thermostat. I wouldn't be so certain of the cooling system operation if I didn't have two totally different year D2's 99/02 with totally different mileage 105k/226K both running 180F OEM thermostats, green 50/50 coolant, and exceptionally well maintained cooling systems to compare against each other.

I started comparing when I got the 99 D2 and I compared a 190F setup to the 180F setup. The temps were much more stable with only a 2F variance vs the 180F that is 6-8F. I liked the more stable temp range, but I didn't care for 206F as an all around temp for here in TX so I slapped in an OEM 180F.

Then I noticed after I got done modifying my Kalahari with the TF Front Bumper, Warn M8000 winch, and TF Front Skid plate and once summer truly hit that anything over 70MPH would cause me to go from 193F to 200F, then it would just as quickly work it's way right back down to 193F. I took the temp spike for all the aftermarket stuff restricting my airflow and basically after 70MPH the air thru the radiator could no longer keep up with the heat being produced. So then I started driving the 99 D2 after I went over every single thing on it I noticed with an original bumper/spoiler the same temp spikes. The only real answer for it is the AC cycling on/off and the condenser heating up and cooling down as my RPM/Speed's aren't changing and the only active thing that could cause the spike is the AC.

Now if you keep getting air in the system (neither of my D2's have any air in them). I'd look into maybe it sucking in air from the throttle body heater plate, heater core orings (floor would usually be wet/damp), or maybe a very small leak in the radiator (my 99 had a tiny leak coming from one of the top screw holes for the fan shroud and it never left a drop on the ground). Neither of my D2's have the throttle body heater plates installed, and I bypassed them using some HD 5/16 line.

I never blew up either of my 03's or my 04 and I was well past 160K on my last 03 without ever tearing the engine down (owned it from 20K and had all service records). I let it idle at Crystal Beach all the time out in the hot sun, I used to take a back road just to open it up every once in a while into the triple digits, and my ex g/f even went as far as to not change the oil in 20K while I was away working. Thing never died. Only issue I ever had was a P0441 fault and that Hyundai part took care of that. Not even mentioning the lovely Houston 2hr commute to and from work each day in dead stop traffic. God only knows what that poor cooling system was doing, but I never saw the red light of death, and if it wasn't for my crazy ex g/f I'd still have that sucker!

I wish I was closer I'd love to stop by and help ya.

P.S. the radiator I put into my 99 D2 that actually was just replaced before I bought it, and I have still had the receipt. It was purchased off of Ebay with free shipping for $99.99. I compared it to my 99 D2's OEM radiator and besides having the SAI temp sensor hole it was identical. So far I haven't had any issues with it, and if I ever need one I'm probably gonna just grab another off of Ebay vs 600.00 from Auto Zone or AB.

 

"Sucking air in?"
I don't know about all of that. I don't have any leaks and bypassed TB. I just assume the upward swing can only be from air pocketed in heater core from previous flush and refills or the radiator isn't cooling like it should be, or possibly undersized. Can't be anything else and from all the drains I have done, coolant always appeared pristine.

When I put my new flex rad hose in and install the gauge I'm going to idle it with the cap off and tank raised again. That seemed to work.


so even with a brand new radiator your temps were doing this? I was also thinkin about replacing the condensor fan with the Range Rover twin-fan unit. Put a controller on it to operate on my designated parameters. One fan at 183 deg on its controller and the 2nd fan wired to the factory loom to coincide with AC function. Sounds good in my head, anyway.

FWIW, I haven't used A/C at all, just recently started experimenting with the Econ mode but that's not the same thing. I haven't been running the AC since I noticed that the Elec-fan doesn't do anything for cooling. I use the AC on road trips when my girlfriend is riding because the operating temps absolutely does stabilize after a few miles driving on the highway at 60 mph. But commuting to work during the week, engine temp would be all over the place esp w AC.

 

The radiator I replaced in the 99 D2 although it was seeping from one of the upper fan shroud screw holes it wasn't blocked or clogged so I wasn't expecting to see any temp improvement. I just replaced it because it was cracked internally and leaking.

 

has anyone taken measurements or experimented with the 99-02 P38 RR radiator? the radiator hose inlet/outlet locations make terrific sense, unlike the D2. don't see why they couldn't use this one, the knuckleheads.

 

hmmm. would look a helluva lot cleaner with an inline mod as well.

 

all of this came to mind. if the radiator dim. don't work out, I'm going to snag one of the water-necks #15,

1999-2002 Range Rover P38A Radiator, Hoses, Cooling & Heating - Rovers North - Classic Land Rover Parts

opposed to the D2 pass-side exit of the coolant outlet tube which pus a damper on my hose re-route ideas every time. The P38 setup is the way to go; almost worth a custom rad build.