I don't have a generic OBD2 scanner with live data feed so I don't know what the actual temperature is. The fan will only turn on if the coolant is over 100 degrees Celcius. That is simply too hot to be normal in my opinion. I guess these trucks normally run at about 90 degrees and in cold weather the temperature is increased by 10 degrees Celsius if I understand it right. That would get it very close to turning the fan on. Running that hot can't be good, no wonder these things blow head gaskets left and right.

 

These trucks run at 100 deg C all the time at idle, turn it on in your driveway and in about 30 minutes it will be up around 103 deg C easily. In the warmer weather they run at about 94 deg C while moving but slowing down and stopping they will jump to 100 easily. That is why a driving around with a scanner hooked is good practice to see how your truck behaves.

 

I got to put an end to that 100+ degree idling. This weekend I am installing an in-line 180F thermostat and totally getting rid of the coolant bypass system. If my heater doesn't work as good after the conversion I might put an additional electric water pump in on of the heater hose.

 

they blow head gaskets because dex-cool eats head gaskets if not changed regularly.

 

We really need to know the actual temp of the engine when idling.
My truck will idle all day long in 95*F heat and never get over 210*F.
Temp hits 210, clutch fan kicks in, cools to high 190's, then heats back to 210...repeat.

 

So am I to understand, that there is a temp adjustment the computer does to the operating temp if the weather is colder outside? Since it has gotten colder Hear I have Noticed My Electric fan Comming on More.

I unpluged the Fan for a test and let it Idle for an Hour and the Temp gauge never Moved from the Middle, so It Seem to Make No Difference If the Fan Was Pluged In or Not. It was about 30F out Side.

 

You truck does not have a temp gauge, it is an idiot light that is made to look like a gauge.

Btw where do you get your delo synthetic oil?

 

It is the thermostat that raises the temperature by 10 degrees Celsius. I don't know how other Discovery owners feel about such a high temperature running but I don't feel comfortable with it. I hate knowing that my truck is running just a few degrees from overheating and dropping a liner. I don't understand the concept of raising engine temperature when it is cold out. My 911 runs at 180 year around, my BMW runs at 190 and heaters work great in both cars. The rest of my in-line thermostat installation parts should be here on Monday so I'll takes some pics and report on how the heater is working. I might even install the auxiliary water pump in one of the heater hoses since I already have the pump. Even if the heater works fine I want to be able to pump hot coolant thru the heater core when the engine is off for those times when you are sitting somewhere waiting and don't want to waste gas on staying warm.

 

My 911 runs even a tad cooler than that, but it's oil/air cooled so that kind of takes it out of the discussion. These modern OB2 systems expect a certain temperature at a given time.

I did the entire hose swap this weekend, including upgrades from Atlantic British. The bleed procedure on this forum is DEAD on. I used my Hawkeye to read the exact temp during the bleed and it never got over 95 deg C. The system is setup to be exact, not too high, not too low, just right on the money.

Now who else cut their finger on that damn lower water pump hose? Fess up! That sucker is in a miserable location even with the idler pulley removed.

 

Mine is a water cooled 996tt. Is your thermostat new or original? Is it possible that my thermostat is bad even though it is new and Genuine?