What Temperature is "Hot"

[coop74]

Ok the new to the Rover Guy here...

I frequently hear not to let this motor run hot. I have the ability to monitor the engine censor by the degree or closer.

On a 4.0 99 Discovery 2 what is the temperature you consider hot. On the hwy she will run 194 at a constant 70 mph actual. stop and go driving it is about 204.

with my ability to monitor the temperature i can also set an audible and visual alarm. What should that temperature be?

Nervous new owner wanting to know...

 

[K-rover]

220+ I would start to worry. The temps you listed above are normal

 

[coop74]

i set the alarm at 215 so i should be golden then...

 

[coop74]

It is common to have large swings in the temperature? 194 to 204 seems to be a pretty big swing?

 

[stu454]

That's not a large swing in my view.

 

[jymmiejamz]

That sounds pretty normal to me. I agree with all of the above statements. The important thing is keeping the coolant and oil full. It is somewhat unusual for them to just run warm unless the thermostat is stuck or the radiator is clogged. Most of the time they overheat because all the coolant leaks out.

 

[coop74]

I just flushed and filled her with DexCool and checked the oil. The oil is very clean on the dip stick and at the full mark. The last owner said he had changed it recently but i plan on changing anyway and new fluids for the Diffs, and transfer case. When i figure out how to make it happen the transmission too... Then maybe on to the secondary systems for brakes and power steering. I actually bought the Rover to have a one as i always wanted one and to have a project car to work on.

 

[jymmiejamz]

If it were mine, I would switch to the green coolant. The service interval is shorter, but the older trucks that used the green coolant didn't eat through head gaskets like DIIs. This is not based on fact, just my personal opinion.

 

[jastutte]

i would get rid of the DexCool and just use the green stuff. The DexCool is not good for the engine and most owner's have switched.

 

[coop74]

i did a bunch of research on that. I think i will stick with the DexCool given i have the updated head-gasket materials on a freshly rebuilt motor and new cooling system. I also have the luxury of having a master tech as a bud and he said to go with the DexCool...

 

[discostew]

Not sure what research would have led you to not running green coolant. But in the future consider that source to be unreliable.

 

[SMLE]

I also would say switch to the green coolant. Continuing to use that DexCool is asking for trouble.

 

[Howski]

If it were mine, I would switch to the green coolant. The service interval is shorter, but the older trucks that used the green coolant didn't eat through head gaskets like DIIs. This is not based on fact, just my personal opinion.

X2. Putting almost 150k between 2 Discos the only HG failure I had was running the DexCool

 

[mbrummal]

x500 or whatever. The problem is with the design of the D2 cooling system that allows (basically encourages) air pockets and what DexCool does with air in the system...

 

[specops1526]

What's the procedure to switching to green coolant? Haven't taken the plunge in years even though I know that dexcool is shit.

 

[jymmiejamz]

I would say pull off the bottom radiator hose and one of the heater hoses. You can blow a little air through to force some of it out. It is probably a good idea to drain and refill twice.

 

[Tugela]

It is probably a good idea to drain and refill twice.

You can also do this:

1. Drain the system of existing coolant
2. Refill with distilled water (a little cheaper than coolant)
3. Run the truck to let the water circulate and mix with the coolant that didn't drain
4. Drain the water
5. Repeat as desired

 

[mlnnc]

Your temps are fine, as is your alarm setting (if not a little low). Remember, the aux electric fan doesn't even engage until 212F.

As for flushing the Dex, what others have written is what I do whether flushing Dex or simply flushing old coolant for new every two years.

Drop the lower radiator hose and drain (when cold). Reattach and fill/bleed with distilled water. Repeat as necessary until there is no sign of color in the coolant, driving at least a few miles in each cycle to ensure all is well mixed. Take your time. Take a weekend. Let it cool down between drain/refill cycles. Usually takes at least two cycles, sometimes three. Once it seems all the old coolant is gone drain once more and then fill with full-strength antifreeze. I use Prestone. That gets the truck to the desired 50/50. Yes, I've done the math.

 

[WaltNYC]

Clearly once the final fill of coolant goes in you'd want a t-stat.

But does it make sense to pull the t-stat whilst performing the drain/flush/refill with distilled water cycle?

 

[MNinWI]

When at a stop light on a hot day, my 03 D2 might get up to 208 degrees. That is from my UltraGauge. I do not think I have ever seen it over 210.