I have read a number of threads regarding this thermostat and have always been sceptical about this so I had a freind send me one from the UK. I have an ulta gauge EM so use this as my monitoring device for my temps. In down town Baltimore it used to be on average 201 - 206 in stop and go traffic and around the belt way it was on average 197.
After half and hour of fitting and bleeding I took it for a test drive and the results suprised me. Same route and the temp has now dropped to 195 - 197 in the inner harbour and on the beltway it was 195 out side temp was 72. So I humbly appolagise to all and admit that i was wrong and fitting the Pel500110 DOES make a difference.
Next month I will be taking a heavy trailer up to Vermont so hopefully this will improve the temps as well.
My Discovery is a 2003 with a 4.6 and 94K miles on it.
Would I recomend this... you bet.

 

Glad to hear yo had good results with that t/stat. I have heard from a number of people on this and other Rover forums that they also had good luck and I have started recommending others to switch over.

 

Bummer, that's not what I wanted to hear, 20 degrees too hot. I think the 82c is when it starts to open instead of fully open like what i'm used to. I used the motorad 80c and got consistent temps of 195. you can pick them up on ebay for 20 bucks. Inline mod and 180*f will get you 170-175

 

I think this sounds like a good solution too bring the temps down a bit. Certainly its cheaper and easier to do.

I still like the in-line thermostat mod as its a simpler design and deletes the fragile plastic tee/vent issue.

My in-line thermostat mod with a 180F thermostat (chevy stat c/w 1/8" hole) runs very consistantly around 82 degC to 85 degC (179 degF to 185 degF) regardless of load. In extreme cold winter conditions it can run a little lower. In hotter weather (I was in MOAB recently) it ran a few degrees higher. I have the alum sight glass and vent combo which makes it possible to ensure that no air is in the system. It's very easy to bleed thru the vent fitting. The engine warms up quickly as well.

 

Hay, which sight/vent combo are you running? Can you post a pic?

 

Yea im curious about that sightglass and vent combo too.

 

I'm debating on which t stat to get. Either the grey body PEL 500110 or the Motorad 439-180 stat. What would be best for an 03 Disco?
Motorad 439-180 Engine Coolant Thermostat | eBay

I want substantial results but I'm afraid to run too cold, nothing as drastic as an inline t-stat.

G-Reeves you ran the grey body soft spring PEL 500110 right? Apparently there is also a black body version with a stiffer spring, just want to confirm with you.

 

I put the grey one in as I had a long battle with high temps (with every bit of the cooling system being brandy new). I dropped an average of 15 degrees and I'm very happy with that.

 

I went for the motor rad version as the grey ones seem to be from Britpart. In the UK they are known as S**tpart. I am more than happy with the results for mine. In the hot weather that we have had this weekend I have not gone over 199 where as before i would have have averaged 206.

 

Where can I get one? I searched the part number on google and and a website called gold coast rovers come up. Yet it says its "$00.0"