just been wondering about coolant flow and the need for a bypass does the radiator eventually get hot with this mod?

IN line STAT
 

JULES, If you become a UK supplier that would remove half the hassle.
It is early days re testing the mod but,so far, I have done 95 miles and the OBD has only exceeded 90C twice and then it immediately dropped.
This is with a 1 mm hole drilled in the stat to prevent an air lock. I do not know if that is strictly necessary. Bearing in mind that it is now the cold season the indications so far are that the diesel is barely capable of generating enough heat even with the top hose blocked except for the
1 mm hole. As i said,to fit a new stat took 28 minutes from start to finish so if it does fail life will be a lot easier.

I think this is an excellent idea, and well done for being the one to try.
I personally think this is a better idea than trying to find a hotter stat to fit the existing housing.
So some form of bypass is not needed, with this housing, or the 1mm hole is adequate, I guess.
This looks like the housing to me:
http://www.meziere.com/ps-571-540-wn0071.aspx

Matt

Housing
 

Yes, that is the one i would recommend at the moment but I have e mailed them to ask if one could be available with a 1 1/2" inlet and a
1 1/4" outlet which would be ideal. I took the precaution of buying a new top hose in case of problems with the mod but, if you think of it it is easier to carry a suitable length of stainless pipe which will easily replace the housing in the event of trouble. If you realise that the original stat is still in place then so is the necessary by pass arrangement as designed for the engine. All you are doing is preventing flow through the rad until it reaches 90.5C which is an increase of 2.5C on the original and seems to be about as high as we can go. As to any problems when the weather is hotter 1. we have the new stat to open and 2. there is the electric cooling fan which, on my car, has NEVER been needed.
I would also point out that when you cut the top hose the coolant loss is only just over a litre.

In line stat housing
 

I have heard from the american suppliers of these housings and he says there is no problem in supplying the unit with 1 1/2" pipe at one end and
1 1/4" at the other. There is no part number for this, he just needs the request. I estimate that this would mean that a change of thermostat would take less than 10 minutes!

been pondering this one I'm no convinced that the position of the stat is correct the only bleed would seem to be from the heater circuit which will be closed in warm weather and I am not sure a hole in the stat is good enough perhaps someone more expert (Jules??) can study the diagram?

http://i724.photobucket.com/albums/w...g?t=1287527634

Sounds like it's working fine to me but with a little more time lag before the new Stat reacts.

The "bypass" as far as I can see is still in place & unchanged.
ie
1.The ball bearing valve in Old Stat.
2. I believe heater circuit is always open regardless of time of year.
(air flaps control temp as opposed to water valves)

if the heater circuit is always open then it should work perfectly as it will form the bypass for the new stat

Must say Frederick, I would like to hear your final results of your testing

In-line stat
 

It is early days of course but so far there have been no problems at all.
I will report any if they occur. The original stat is still in position so the original design is still working but when the stat opens prematurely the hot water does not reach the radiator because of my additional one. The advantage to me is that should the original stat ever stick in the closed position (never reported yet) there is no way the car could be repaired easily. If the in-line stat became faulty it could be replaced, or the whole housing replaced by a piece of stainless tube in about ten minutes.
Jules is interested in this,so, knowing him, a comprehensive quality package may be in the pipeline?