Are you sure that was due to a bad alternator ...or the belt routed incorrectly? That can cause flickering too.

Electric current travels from neg -> pos because electrons (which are neg charged) and pass to adjacent atoms ..therefore all electric current in a Disco travels from the Ground, through the ground cables, and makes it's way back to the pos terminal. So, yeah, like you guys say it's real important to have good engine/frame/body grounds and batt cable connections, considering all the sensors on your engine and rest of the vehicle.

 

I’m not sure if you said, but how soon after replacing all that did you notice the temperature spikes?

Also, I noticed you didn’t say that you replaced your thermostat? It’s a quick and easy job, I think it’s just removing a connector hose and then 2 bolts.

Every time I’ve needed to drain coolant and then refill I experience the same thing, but the problem is usually always air pockets that haven’t received coolant yet. I know many people on this forum advocate jacking up one wheel of the disco to add coolant and “burp” the system, but I’ve always been able to avoid that by letting it get up to operating temperature and then shutting off when it starts to get above 190° and then topping off with coolant in the resevoir.

Common places you may be seeing a leak would be the resevoir cap (more notorious with the black coolant resevoir) or the Heater Matrix

 

replaced thermostat 3 times. currently running a 180, which is too cold to develop heat for the winter. Temp gauge fluctuation started right after Igot the truck over a year ago. My mistake for believing the gauge. I replaced everything trying to get the gauge to settle down, starting with thermostat, then sensors, then belts, radiator cap, hoses, etc. last replacement was the radiator. That was when I noticed with the gauge pegged, the overflow bottle wasn't even hot. This is my 2nd Disco and I went through the whole front end to get the death wobble out. drove it for 7 years until the kid blew up the motor.

 

So my ideal temperature for my Land Rover is between 180-185°F… this produces plenty of heat? When you say heat for winter I’m assuming you mean in the vehicle? Does the air coming out of your vents run cold? Wondering if there is something wrong with the climate control?

 

When the temperature outside is -20 degrees, a 180 thermostat will not produce enough heat to warm up your toes in a disco 1. also in freezing rain, the windshield will ice over in a few minutes. The stock thermostat is a 195 and that is what I would go with. I went with a colder one thinking I had an issue with the radiator and it would help. Turns out my radiator was OK, as the new one acted the same way as the old one. I was unable to find the time to reinstall the 195 thermostat and suffered through the winter months. luckily the heated seats worked or I would still be thawing out.

 

jimvw57, are you suggesting that the difference between 180 deg coolant running through the heater core and 195 degree coolant makes a difference in how the cabin air is heated?

I am struggling to understand how the extra 15 degrees makes a difference even in your artic temps (unless you have the windows open)

 

One of my favorite things about Discos is the heater really puts out. The t-stat shouldn't change that too much. If the vent flaps get stuck, then you could get cold, I guess.

 

I have seen temps (on the OBDII scanner readout) while driving in sub zero temps running around 160 degrees and that is after driving for 45 min at 45-60 mph in a snowstorm with the 180 thermostat. and the air from the heater is at best almost warm. Not enough to warm your toes. Not so with a 195 thermostat. both thermostat were Land Rover stamped units. not aftermarket ones. Usually they do the job, unless you have a leaking floor or firewall.

 

Maybe 180 t-stat was stuck open?

 

I have experienced this personally and indeed the cabin remains quite cold. I would bet your suggestion is correct. The t-stat rating is not important if it open at all times.