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-   -   Thermostat ? (https://landroverforums.com/forum/discovery-ii-18/thermostat-127211/)

thclark Nov 18, 2025 08:40 AM

Thermostat ?
 
New Guy here..
I'm about to do a full flush of coolant. While I haven't had any issues with overheating during my short ownership, I believe its the original thermostat and I'm at 95K miles. Thoughts? Seems easier to do when its empty of coolant and not have to stress it for the foreseeable future?
Any advice on thermo welcome - was planning on replacing with the Atlantic British one here if I go this route: https://www.roverparts.com/engine-co...ats/PEM100990/

Thx!

Externet Nov 18, 2025 08:48 AM

Advice ? ---- Flush the cooling system with some chemical that will dislodge-dissolve deposits, then replace it with an on-line thermostat blocking the bypass path and throw the stock thermostat in the garbage can.

gecko951 Nov 18, 2025 11:04 AM

Do you have maintenance records? Do you have a OBD2 bluetooth monitor, scanguage or ultragauge so you can see the actual coolant temps? (hint-hint, the factory gauge is binary: OK or OVERHEATED)

If you're just doing coolant and thermostat then I would definitely go with the Extinct inline thermostat and silicone gasket because the factory style thermostats are a b*tch to swap in the field and even worse, NIB thermostats are known to be inaccurate so you might swap and overheat the engine.

READ: https://landroverforums.com/forum/di...thread-105010/

thclark Nov 18, 2025 11:53 AM

Great write up - I need to find my obd2 reader...this is getting out of hand quick :)
Can someone tell me (for a guy living in Vermont weather) - which I should be going for if I decide to go the inline route:
160 Degree high flow thermostat element
170 Degree high flow thermostat element
180 Degree high flow thermostat element
195 Degree high flow thermostat element

If memory serves the stock ones goes up to 180 - would I do anything different for daily driving...very mild off road use (think camping and motorcycle trips). Thx!

gecko951 Nov 18, 2025 01:01 PM

The stock style tstat is closer to 195F and 195F is OK most places in the colder months of the year but it doesn't give much safety margin in the summer. The advantage of the inline thermostat with the silicone gasket is that it makes thermostat swaps practical so you could run 195F for winter and 180F for summer or you could choose to run the same temp all year round....just depends on the local climate.

Extinct Nov 18, 2025 07:35 PM

As you are a new owner, read all of this: https://landroverforums.com/forum/di...s-mods-126943/ Get an ultragauge. Change any cooling system component older than 10 years old. Also read my blog post here: https://extinctmotorsports.com/the-engineers-blog/ If you have an 03 or newer go with 180 if you want year round, 02 or older you can use a 170. Winter and summer thermostats are not a bad idea, but if you really want year round, use the 180.

thclark Nov 19, 2025 07:40 AM

Great info Extinct - thx!
Ordered the inline
One question...what coolant (brand,type,color etc.) are you using in your Disco's with this setup?

H20nSnow Nov 19, 2025 08:57 AM

Most people here have switched to green. It eliminates the clogging problems with orange. In the 2000s, orange was the best for aluminum blocks and heads, but that is no longer true.

Extinct Nov 19, 2025 08:16 PM

Green, its cheap, last a long time. Dexcool is fine on aluminum block/rover engines. Not as good on cast iron.


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