Diesel thermostat definative answer - Page 10

rossocorsa · 19th October 2010, 07:27

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

wuzerk · 19th October 2010, 07:41

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.

Matt1960 · 19th October 2010, 08:53

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

wuzerk · 19th October 2010, 10:44

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.

wuzerk · 19th October 2010, 19:23

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!

rossocorsa · 19th October 2010, 22:37

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?

Jules · 20th October 2010, 00:33

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)

rossocorsa · 20th October 2010, 07:08

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

tony_fry · 20th October 2010, 07:17

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

wuzerk · 20th October 2010, 07:51

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?

19th October 2010, 07:41	#92
wuzerk Passed Away Rover 75 CDT 03 auto Conn. SE Join Date: May 2009 Location: London Posts: 2,885 Thanks: 104 Thanked 254 Times in 204 Posts	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.

19th October 2010, 10:44	#94
wuzerk Passed Away Rover 75 CDT 03 auto Conn. SE Join Date: May 2009 Location: London Posts: 2,885 Thanks: 104 Thanked 254 Times in 204 Posts	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. Last edited by wuzerk; 19th October 2010 at 10:52..

19th October 2010, 19:23	#95
wuzerk Passed Away Rover 75 CDT 03 auto Conn. SE Join Date: May 2009 Location: London Posts: 2,885 Thanks: 104 Thanked 254 Times in 204 Posts	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! Last edited by wuzerk; 19th October 2010 at 19:46..

20th October 2010, 00:33	#97
Jules This is my second home ZT 260 SE Twilight and 10 other 75 ZT's :O Join Date: Jan 2007 Location: Conwy NORTH WALES Posts: 11,094 Thanks: 512 Thanked 1,116 Times in 763 Posts	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) __________________ [SIGPIC][/SIGPIC] Newbies do now!! 1. Plenum drains..all 3 or 4 year dependent 2. Cooling fan..All speeds functioning 3. Bonnet cable divider block

20th October 2010, 07:17	#99
tony_fry I really should get out more....... BMW I3 Join Date: Nov 2006 Location: South East London Posts: 2,224 Thanks: 31 Thanked 77 Times in 61 Posts	Must say Frederick, I would like to hear your final results of your testing __________________ Regards Tony Membership No 135

19th October 2010, 07:27	#91
rossocorsa Posted a thing or two None Join Date: Feb 2010 Location: GRIMSBY Posts: 1,243 Thanks: 0 Thanked 1 Time in 1 Post	just been wondering about coolant flow and the need for a bypass does the radiator eventually get hot with this mod?

19th October 2010, 08:53	#93
Matt1960 Gets stuck in Rover 75 Connoisseur SE CDT Tourer Join Date: Sep 2009 Location: Herne Bay Posts: 654 Thanks: 1 Thanked 4 Times in 4 Posts	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

19th October 2010, 22:37	#96
rossocorsa Posted a thing or two None Join Date: Feb 2010 Location: GRIMSBY Posts: 1,243 Thanks: 0 Thanked 1 Time in 1 Post	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?

20th October 2010, 07:08	#98
rossocorsa Posted a thing or two None Join Date: Feb 2010 Location: GRIMSBY Posts: 1,243 Thanks: 0 Thanked 1 Time in 1 Post	if the heater circuit is always open then it should work perfectly as it will form the bypass for the new stat

20th October 2010, 07:51	#100
wuzerk Passed Away Rover 75 CDT 03 auto Conn. SE Join Date: May 2009 Location: London Posts: 2,885 Thanks: 104 Thanked 254 Times in 204 Posts	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?