Overheating issue again

wilsonsandy07

Member
Aug 7, 2019
10
0
las vegas
I know there's a million overheating threads put my problem is more persistent so I figured id seek some specific help.
Basically living in Nevada its very hot especially summers so the discovery is going to run a little hot but I cant figure out how to keep it down.
I've started with a new heavy duty fan clutch, new 180 thermostat, coolant flush(clean), new water pump with the fan clutch, no visible leaks, no rotted hoses or lines, and ive bled the system to the best of my ability with the front end raised and all that.

Its idles fine, ive had it sitting for like 30 minutes with a high idle by the way that I'm in the process of fixing, and it wont go above 200 but after driving for a good while it starts to climb. it doesn't get over 220, but it gets close and that's too hot for me to be comfortable continuing. with the AC on the temp will either rapidly spike or act normal and slowly raise while driving. I know its a lot of info, but my ultragauge also says I have a cat 1 bank 1 sensor that's way over heat, could that have some sort of effect?

- idle temp is fine
- after driving for a while, slow rise to 210 ish
- with AC on it either doesnt react or spikes rapidly
- ultragause gives cat1 bank1 sensor very high heat (not sure if this is relevant)

thanks all, could really use some help to get this thing off road reliable. 97 Discovery 1, v8, auto, 175k
 

p m

Administrator
Staff member
Apr 19, 2004
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La Jolla, CA
www.3rj.org
Check the temperature drop across the radiator using an IR gun - it should be about 15-20F difference side to side. Better yet, if you can aim the IR gun to different points in the radiator, check if the temperatures are the same top to bottom.

What you are describing is exactly how my D1 used to run before heavy-duty radiator and 180F thermostat.

I wonder if the cat is partially broken and plugged on the side where the sensor temperature is shown as very high (don't think I even knew GEMS measured it).
 

wilsonsandy07

Member
Aug 7, 2019
10
0
las vegas
Check the temperature drop across the radiator using an IR gun - it should be about 15-20F difference side to side. Better yet, if you can aim the IR gun to different points in the radiator, check if the temperatures are the same top to bottom.

What you are describing is exactly how my D1 used to run before heavy-duty radiator and 180F thermostat.

I wonder if the cat is partially broken and plugged on the side where the sensor temperature is shown as very high (don't think I even knew GEMS measured it).
I read that the cat temp doesn't really matter because they don't measure it like you said, but ill try and get my hands on an IR gun and see how the temps are all over. I'm suspecting a radiator swap will be my cure I was just hoping to avoid it because the PO said he already swapped it not long ago. do you think the cat temp would effect my high eng temp at all? maybe pushing it back after a while of running because its partially clogged or something?
 

wilsonsandy07

Member
Aug 7, 2019
10
0
las vegas
Makes sense, it looks fairly new, a few bent fins here and there but deff not the worst radiator ive ever seen. sounds like ill be ordering an aftermarket sometime soon then, thanks for the input
 

bradartigue

Well-known member
Mar 7, 2018
112
17
Sandy Springs, Georgia
Higher than normal cat temps matter because they may indicate blockage in the cat. Blockage in the cat equates to the engine doing more work than necessary. It gets hotter.