Hello everyone!

My 99 Disco 2 is running too cold.

It was really, really cold yesterday. (-35c)

She started up fine. After about 10 minutes, NO HEAT. Nothing. Cold as cold can me.

The heater core hoses were still cold. There was a slight bit of coolant (about a tablesoon) on the snow below the front of the engine and a little on the front end part. Coolant level was good.

HISTORY;

I changed out my coolant last summer (Not Dex!). I also installed a new thermostat because mine was looking old, even though it was functioning fine. My ultra gauge was showing around 180 to 190 before. After changing the thermos stat (purchased from the dealer, he said it was the a 180 - the liar).
Ran it on the highway and it was high teens! I brought her home and put in the original thermostat again and it's been back down to around 190 ever since. Boiled the old one and it opened around 205!

I purchased a new 180 thermostat online and it's sitting in the back of the truck now.

Back to yesterday;

I went back outside and started the truck. I've had the ultra gauge unplugged so that I can run a fleet tracking unit in on the obd2 port (requirement of work). I plugged the ultraguage back in.

I started the truck and let it warm up. The heater core started working. The truck got up to 150 and stayed there. Coolant levels were good. Hoses felt hot and pressured. No leaks could be detected. It never got above 150.

I took it for a drive around the town that I'm working out of, and it climbed to 156. The heater core was pushing heat, but not quite as much as it normally does. After 20 minutes of driving around

I'm going to find a shop today and have them swap out the thermostat. I don't really want to do this in the hotel parking lot and make a big coolant mess. And it's still pretty cold out.

I have ran this truck many times in this cold weather before. It has always gotten up to 190 and the heater has pumped out adequate heat.

Any ideas other than an old thermostat stuck open?

Thanks.

 

my guess is the stat.

 

I can't get her into a shop until monday.

I took it out for a drive around town today. It is only -9 c outside.
It got up to 160F.


I noticed the fan spinning the whole time. I think that is normal. It's got a slight Peanut Buttery feel to it when I try to spin it manually when it's not running.

I put my hand on the bottom hose exiting the radiator before it goes into the thermostat. COLD! No heat. Bottom of radiator itself cold to touch. Top of radiator is warm to touch. This is after warming it up for 20 minutes and driving it around for 30 minutes.

Dashboard temp gauge is centered and the Ultragauge sticks mostly around 156 F.

How do I tell if my water pump is toast? If it's a stuck closed thermostat, or a non functioning water pump, wouldn't I be overheating?

Going to read through the rave a bit and find out where the temp sensor is.

Any thoughts or advice is greatly appreciated.

 

water pump is manually driven so always pumping when engine is running. not a cause for under heating. but it can leak and wobble when it is wearing out.
and since you are running cold a stuck open not closed stat would be the failure with that.
testing would require removal of the stat and place it in heated water to see what temp it opens...

 

no need to seek out the sensor for the gauge. that turd shows mid point, in the dash, from 150 all the way to 250......so it is a circular waste of dash space.

 

if watching real temps through ultra gauge, you could put a grill/radiator blanket on to help keep the temps where you want

 

Thanks Dusty.

It's been running around 190 (via ultragauge) in these cold temps until now. Or at least recently. I disconnect the ultragauge when I came out to this job at the beginning of January.

Everything was looking good then. The truck mostly sits while I'm out a work except for the occasional trip to the field and around town for groceries.

I'm not exactly sure when this happened. I'm suspecting the other day when I started it on that extremely cold day and I had ZERO heat.

 

New thermostat solved the problem. But most of you already knew that it would!

 

Before installing a new thermostat I like to test it, in a pan of hot water. Get some hot water from the tap, put the thermostat in, along with a thermometer. Check that the thermostat begins to open around the rated temp, and then fully opens at, say, 10F higher. Then check it closes fully when cooled down again.

NB : The rated temp is the "begins to open" temp.

I had a problem with my Jaguar XJ8 running cold on cold days, the thermostat was fine but the shop had omitted the rubber ring that goes around it, and seals it. Result is that some coolant is always leaking past.