Hello all, in pursuit of a cooler running engine I did the inline thermostat mod. I tried the 180 degree genuine thermostat which got me down to 207-208 at idle.

I used the bleeder valve with the sight glass Stealth Conversions V8 Cooling System Parts - Coolant Sight Glass

I drained the air and now getting operating temperatures in the 183-189 range (188.6 at idle). I had difficulty getting the gates 23405 hose on the end that goes towards the engine (I think its 1.5" ID hose as opposed to 1.25") that took me a good hour to get on. Drilled a 1/8" hole in the thermo and positioned it up by marking the top of the housing with a sharpie. Cut the hoses with a utility knife and used a dremel for the shroud. Sorry for the dark picture below in my garage - I can take one in the daylight if anyone is really interested.

Took me a few hours (not at all experienced wrencher).

Instructions I took from here Inline Thermostat - LAND ROVER CLUB V.I.

Thanks to the forum for this mod, really helped with the cooling system.

 

Just got my done over the weekend, seeing about the same temps as you.
i had a hard time with the lower hose also, a little liquid soap and it went right on

 

I don't know why they suggest that BMW lower hose in treads, it's wrong and clumsy, I went to parts store a while back & since I go there often & guys working there are very friendly they let me go to the back & go trough their selection of Gates hoses,, after an hour I found the perfect hose for lower radiator to engine, it's Gates 22073,, fits like a glove, & looks like it was made for the job,, I have done 2 inline mods using this hose,, I used superstat 45967 T-stat after modification to it, & truck idles at 176- 178*,, at cruising speeds stays at 180-182,,,
And it builds up heat for heater much faster than original setup,,

 

I'm getting the parts together for this and have the thermo housing that is 1.5 and the glow shift connector that is 1.25 (32mm), double checked part numbers before ordering. Is that correct to have the 2 different sizes?

 

You need the 1.25 inch housing (meziere wn0071)

 

Dang, I did order the 72 instead of the 71. Thanks for that!

 

Actually you need 1.33" housing (34 mm) for both, it fits best, at least for me,, 1.25" was too skinny.

 

Call me daft but is the old thermostat removed or is it bypassed when doing this inline mod?
I can't seem to understand what happens to the 3 hoses on the old thermostat. I need pictures. lol

 

Juke179r I must be daft too because I was going to ask the same question!

 

Yes, old original T-stat is discarded,,, Upper hose from engine that was going to plastic T, now attaches to inline T-stat housing & you put a bleeder assembly after that and then connect to upper Radiator hose,,, bottom hose from radiator connects to lower inlet, (where original T-stat middle hose was connecting to),,
What you are actually doing is discarding the hose that was coming down from original plastic T,,
(For lower hose use Gates 22073, it fits perfect from radiator to original plastic 3way thing that goes to water pump lower section)
I hope it's clear enough,, good luck,