97 discovery 1, 175k miles

once the engine is up to operating temperature i am getting temps of up to 220 while going at trail speeds or being stopped. I can manager to cool it off if I’m constantly moving.

here is everything I have done to the vehicle in the year I’ve had it that has to do with cooling.

180 stant thermo
new coolant reservoir
new reservoir cap
all hoses flushed and serviceable (not brittle or hard.)
new Nissens radiator (this month.)
new fan
heavy duty or severe duty fan clutch HAYDEN.
engine temp sensor
new water pump along with fan clutch


I have a p1191 code which I believe is something to do with the CATS/O2 sensors, but I’m not sure that it has anything to do with my heat problem.

it takes a while to get up to temps of 200+ but once it does it’s hard to cool off. Can anyone give me some advice here I’m desperate with this damn thing lol

 

If your engine is running lean then excessive heat is a side effect. O2 sensor codes could be contributing to this.

 

What are you using to see those temps? If it is just the gauge, you need more. An OBDII dongle and smart phone app are the way to go.

You've covered just about the entire check list. I suppose the next thing I'd do is swap out the t-stat and check the new one in a bucket of boiling water to make sure it opens at the correct temps. Could also be (and I don't mean to insult) that it is installed backwards. The spring should be oriented toward the rear of the truck. The 'jiggle pin' should be at "12 o'clock".

CEL codes can be found here....
https://www.obd-codes.com/trouble_codes/landrover/

They also can be found in the gems_obd manual in the D1 section of the google drive link in my sig.

Ahab is of course correct, but 1191 means the computer is not seeing readings from either post-cat O2 sensor so unlikely to be the source of the problem. Could be, but I'd look elsewhere first.

 

Using ultra gauge to read temps, and the T-stat is definitely installed correctly and off a cold start I can tell it functions but maybe it’s not at the right temps.

The code says “oxygen sensor heater circuit open downstream” What is the fix for this code? Is it the connections of the O2 sensor or the sensor itself or could it be a clogged cat?

 

Get the front passenger side up as high as possible and do another coolant bleed.

 

Replacement. I agree with WaltNYC that a downstream sensor is unlikely to affect mixture very much, if at all, and this likely points towards a problem with the cooling system itself. A severely plugged cat might cause some temp problems but you would notice it as a performance loss first and foremost.

 

So now p1194 popped up and that’s high resistance on the downstream sensor, but I’m going to bleed again and see if I can get anything else going. Will probably order another thermostat too and see if that helps. Maybe a better aftermarket water pump will help move things along

 

So after the bleed I learned a couple things. My Tstat is working as advertised. It’s fully open at 180 I can watch the coolant in the tank drop down and the temp will push back down but after a few minutes of cycling it allows itself higher and higher temps. So when it first hit 177 it went back down to 165, but after 10 minutes or so it struggled to stay below 180. Which is keeping the thermostat but not dropping temps. This is only ten minutes after turning the car on for the bleed

 

also another update, turning AC on makes the temps go up much faster and higher. When bleeding I have heat on low, once I don’t have any bubbles I put ac on full blast like I would be if driving and my temps go upwards of 200 just sitting idle

 

Make sure the coolant is a 50 50 mix of coolant and water, too much coolant will affect the ability to transfer heat. Also if the radiator is blocked (the tubes inside it) also no cooling. lastly, air flow through the radiator is needed for cooling too. Sitting stationary with little to no airflow will cause an overheat. Make sure the cooling fan is working, either an electric one or a viscous coupling fan run by the belt off the motor.