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-   -   Diesel thermostat definative answer (https://www.the75andztclub.co.uk/forum/showthread.php?t=68468)

Jules 28th January 2016 22:15

Do not drill a hole.
The system is self bleeding once the stat opens for the first time.

ie
You may see the temp rise to 110C once after refil then a sudden drop to 88C

Busboy 28th January 2016 22:29

Quote:

Originally Posted by Frank Incensed (Post 585930)
Well done on getting the response, even if it's not what we were hoping for.

I'm still trying to find an alternative thermostat and I'm off to my local parts dept tomorrow, with what I've found. But BMW's reply that it would'nt make any difference doesn't bode well. This is born out by tales of good mpg obtained by members with stuck-open thermostats.

As for the motor being too (thermally) efficient, then why does it use so much diesel for the power output? As T-Cut said, it seems the cooling system is the thing that's too efficient! James' idea of restricting the air flow to the radiator has been put to me by others and currently seems the best solution. Perhaps someone can devise a way of diverting some of the air blasting through the grille into the air intake.

Hmmm! This is a long and very technical thread, I have a vested interest because I have a late CDTi.

As a more aged member, I recall that when I had classic cars in the 1970's /80's some of them had black leather radiator muffs fitted, which greatly helped in reducing cold air flow when driving off in the winter with an ice cold engine. Also London Transport even used a sliding steel panel on the RT Type double decker bus that could be risen in cold weather to reduce air flow, as the 1939 AEC engine was also thermally efficient, so there you have it folks, 2 vehicles 60 years difference and technicnically streets apart but one common souoution , Stick a muff on the front, I have and it works a treat!!! :cool::}
;)

Jules 28th January 2016 23:05

A radiator blind may help the running temp in certain circumstances but it won't make any difference to the warm up time because there is no coolant flow through the rad during this phase until the stat starts to open.

Busboy 28th January 2016 23:15

Thanks for your reply Jules, I will let you play around with my car when I come up to see you later in the year!

clf 28th January 2016 23:20

Quote:

Originally Posted by Jules (Post 2206833)
A radiator blind may help the running temp in certain circumstances but it won't make any difference to the warm up time because there is no coolant flow through the rad during this phase until the stat starts to open.

I can attest to this, having blocked off my upper and lower grilles, with duct tape. Although it did increase the running temp literally by a couple of degrees, it simply wouldnt be worth it.

BadgeStar 29th January 2016 04:23

Quote:

Originally Posted by Jules (Post 2206785)
Do not drill a hole.
The system is self bleeding once the stat opens for the first time.

ie
You may see the temp rise to 110C once after refil then a sudden drop to 88C

Thanks Jules ..... Bleeding was my next question!:}

Barry.

PaulR 29th January 2016 09:08

I cut pieces of corrugated plastic sheet (the type you get pinned to the garden wall advertising the builder when you have had new windows or similar) to shape. These just slot in nicely behind the radiator grille to form an invisible radiator muff, admittedly only covering half the radiator. I used it during the very cold winters we had a few years ago and felt that it did help to keep the engine warm when the heater was running, but it might have been wishful thinking!

FrenchMike 29th January 2016 09:51

Quote:

Originally Posted by PaulR (Post 2207011)
I cut pieces of corrugated plastic sheet (the type you get pinned to the garden wall advertising the builder when you have had new windows or similar) to shape. These just slot in nicely behind the radiator grille to form an invisible radiator muff, admittedly only covering half the radiator. I used it during the very cold winters we had a few years ago and felt that it did help to keep the engine warm when the heater was running, but it might have been wishful thinking!

IMHO,it'useless as the role of the thermostat is to maintain the engine temp
by allowing more or less coolant through the radiator ...:shrug:

paulf 10th July 2016 19:24

Quote:

Originally Posted by paulf (Post 628454)
This seems a worthwhile mod for those with thermostat problems but has anyone thought of using a Renault in hose stat?.It seems to be a common mod on Vauxhalls to avoid removing the cam belt when the thermostat packs up.
My thermostat seems marginal at present as its running at 80 to 83c and if it gets worse im going to try an 88c Renault 5 thermostat in the top hose.
Paul

Well 6 years latter I finally replaced my 300,000 mile 1999 cdt with a 2004 cdti and the first thing I found when I had it on the road after replacing clutch and front suspension bushes and strut top bearings, was that it didnt warm up. Even on a hot day it only got to a quarter on the gauge and returned 42mpg and so finally got to try the mod for myself today, it now gets to normal on the gauge in a couple of miles and engine response is a lot better, I just need to see what effect it has on fuel consumption as my old car used to average 49 to 50 mpg.
Paul

paulf 10th July 2016 19:28

Quote:

Originally Posted by T-Cut (Post 2088971)
Which reminds me. Has anyone got an update on the performance of the 'Mk3' stat from DMGRS?

Maybe it's not been in use long enough yet, but it would be interesting to compare the longevity of Mk1, 2 and 3. As far as I'm aware, the Mk1s are still going strong though maybe few in number(?). The Mk2s are the reason for this 140 page thread and the Mk3s are hopefully an OEM style permanent fix.

TC

I assume that my 1999 car was a mk1 thermostat as I have owned the car for 7 years and never had a problem with it, my replacement is a 2004 car and the thermostat had failed.


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