Hey all, just received a 2003 disco that had been in a small accident for super cheap. Anywho, she runs a little on the warm side holding between 204 and 212F. My rangie holds pretty steady between 195 and 201F. Is there a warm weather/cold weather thermostat? If so, is there a part number for the warm weather one (if one exists)? I'd much rather have it run on the cool side than hot. Thanks in advance!

 

No there is no t-stat temp choice for the DII. (that I know of)
Do a complete cooling system flush with a off the shelf flush kit, then refill with a universal pre-mixed aluminum safe coolant and see what the temp runs.
I would just replace that t-stat to begin with, but a cooling system flush would help remove and radiator clogging scale and sludge.

 

When replacing the stat pay attention to four small holes in the surrounding mount area, these also get clogged with scale and gunk, there have been recent posts with photos. And of course the regular mud clogged exterior fins on the radiator, etc.

 

I did a complete system flush already and there doesn't appear to be much build up in the system. She still runs steady between 208 and 212F. Which IMO is a little too warm. The thermostat looks a bit old, I will replace it first and hope for the best. Hopefully it will bring the temps down. Aside from that, she runs like a champ .

I could have sworn there was an option for a hot or cold thermostat... Maybe it was an aftermarket thing, or rangies have the option, idk. Saw it somewhere lol.

 

While there is not a "factory" version of winter / summer stats, a number of posts have been placed by memebers who run 180 degree stats. I run one that way. However, keep in mind that the stat does 2 things - determines how fast engine will warm up, by staying closed (remove stat and engine will only come up to 135 - 145, in my case), and the minimum temp the cooling system will maintain (if stat is not sticking or defective).

Once the stat is open, temp is free to increase, if the cool water coming from radiator is more than offset by much hotter water from engine. The water has to "take a break" in the radiator to cool off (by stat open/close action), if flow is always constant eventually the engine on warm days can out produce the radiator effect.

If you run a 180, truck may still get too warm, because you have something else going on. That could be, in no particular order:

radiator fins clogged with ???
AC Condenser fins clogged
AC electric fan not operating or reversed direction (really bad at idle)
radiator internal coating with junk and scale (hard water, stopz leekz)
[D1 rads are brass/copper and can be rodded out, D2 are aluminum, can be flushed out by indy rad shop, but may not be good candidate for rod out]
water pump could be marginal (easy to replace)
belt route could be wrong
thermostat sticking
small thermostat housing bypass holes blocked or trash trapped by stat
low coolant
leaking coolant
head gasket
slipped liner/cracked block
throttle body gasket leaking
heater core / valve issues
fan clutch weak (if overheat at idle or slow speed)

So when doing a cooling tune up, check all the little wierd cheap things, they can all add up. Pix of a stat with what is left of coating by "stopz leekz" ("water glass"), which tried to stop the stat from leaking - more fell off when I removed stat; water pump (left old, wobbly, worn out bearing failure, ate up metal 175K, coated with stopz leekz), clean one (D2 at 115 K), close up of impeller (scale due to hard water, etc).

 

As mentioned there is only one t/stat for a D2. Some have tried replacing the factory t/stat with a GM type and yes, it will help move more coolant and run cooler but it does cause problems getting the engine warm enough, in the winter, to allow the ECU to go into closed loop.
As mentioned in the last post, there are a ton of items that will cause this 03 to run warm and I would start there.

 

Assuming all the little things that have been mentioned have appropriately been checked and managed etc...
.
Mike, isn't this more of a potential problem that is mostly dependent upon location specific winter conditions? Being more prone in harsher Colorado Rockies/Mid-West/Northern winter versus a milder California/Pacific Coast winter etc?
If I were to use the GM stat and make an inline mod (which I'm about to), and if I encountered this problem, I'd consider mitigating it by making "seasonal" stat swaps. (using the lower temp stat (180) in the summer and a higher temp stat (196) in the winter.). If I were to plan ahead and use the right hose/components/hardware and tools (perhaps one way/shut off valves and or coolant hose clamps/pinchers etc etc), I might be able to make the swap with minimal/negligible coolant loss and mess. This would make seasonal stat swaping a horse of a different color.
Even without "over-engineering" the hose plumbing for "easy" swaps, some may consider the benefit of cooler/optimal engine operating temps (meaning not over 196 but not less than 180-185) worth the "hassle" and effort of seasonal swaps.
Anywho, I'm not going to bother giving seasonal stat swap any more thought unless I encounter a problem. I'll be using my OBD scanner/live data monitor to track my temps and open/closed loop operations.

As an aside, I thought our Bosch Motronic electronic fuel injection controllers use the exhaust gas temps measured by the pre-cat O2 sensors to determine when to switch from open to closed loop? I didn't know engine coolant temp was used as well.

Cheers,

Thomas

 

For D2 stat photos of clogged holes - see https://landroverforums.com/forum/di...ermostat+holes

 

If your cooling system is in good order and of adequate size your engine will run right at or just above the t-stat temp.
I have a 195* t-stat and my truck runs at 196* all day long no matter what, off roading aside, then it runs around 200*.
But your cooling system is smaller so a 180* is what you want and you should run around 190* or so.

 

You might want to read the Rave article on our t/stat and heater core relationship, makes for good reading.