Lazy Thermostat on 2.0 CDT with BMW Engine

PaulPJ · 11th March 2009, 11:59

Hi Chaps, I think I might have a lazy thermostat as it takes 5 miles or more to warm up and temp drops a tad when queuing on the M3 (as you do). I have read various threads about changing the thermostat without changing the water pump and that its easier on the BMW engine despite what Mr Haynes says but I dont even know where it is on my car. Does anyone have pictures of how to change it or can someone clever person do a 'How to'. Bring back the crossflow engine, atleast you knew where everything was and could do almost everything with any old tool. Paul

Evansabove · 11th March 2009, 12:20

Paul,
I had the same symptoms and got a new thermostat fitted but the old one was full of "crud" which stopped it closing properly. A good flush out of the cooling system may cure it. My garage said it was difficult and had to take the water pump off and being a friend I believe him. As to the slow warm up, diesel engines are so efficient they take linger to warm up hence the need for a fuel burning heater for the cold weather. I drive through the forest from Bournemouth each day and it can easily take 5 miles before I'm up to temperature.

HTH

John

PaulPJ · 11th March 2009, 12:29

Hi John, thanks for that. Is it easy to flush out and refill engine? I worry about it because of airlocks and damage to Head Gasket etc etc. If it's something that is easy to do I will get a gallon of OAT and do it when I have a spare weekend. Thanks Paul

steve107 · 11th March 2009, 13:17

i had mine changed at local garage .they did not take water pump off .take drivers side top mounting bracket jack up .sorry take enginre cover plus air filter off.it took the garage about 1.30 hour. charged me £40 to fit .thermo cost£37 from rimmers .its not hard just figerley .

Livermpj · 11th March 2009, 17:23

Hi Paul,
Coolant change on the CDT is easy peasy, IIRC there's only 1 bleed point (above the FBH unit).
Not sure about the crud theory, mine's 8 years old and clean as a whistle. In theory the OAT should prevent corrosion and sludge formation. I've only changed the coolant once (at 4 years), due again this spring.
It's vital you use OAT or a compatible substitute, I palyed safe and stuck with MGR OAT (Orange) - it's not expensive.

hth,
Pete.

PaulPJ · 12th March 2009, 07:28

Hi Pete, thanks for that. The thermostat seems to be behaving now so maybe it is just me. I think the car is due a coolant change soon so now know its easy I will do it come the warmer weather. Thanks again. Paul

skyrise · 30th March 2009, 07:13

Hi ya... My first post...

and its a question like this one..

I have a 6 mile drive to work in the morning and my car got just over 1/4 warm.. is this about right for the CDT? it was 0.5 oC out side :\

shakennstirred · 30th March 2009, 10:13

the BMW engine is very efficient and will cool a little if on tickover
5 miles to warm up isn't bad depending on outside temp

T-Cut · 30th March 2009, 10:40

A more meaningful idea on how the system performs is to use the diagnostics mode to provide the engine temperature in degrees Centigrade. The temperature gauge is relatively meaningless other than indicating that a minimum coolant temperature of 75°C has been reached.This is the temperature when the needle first touches the 9 o'clock (normal) marker. Beyond that, little information can be got from it. Remember that internal combustion engines run at their most efficient in the 95-100°C area, so the longer it takes to reach this band, the more fuel will be consumed. An engine running at too low a temperature may also suffer more wear.
From my readings, the diesels rarely run in the optimal temperature band and are typically running too cool. To a large extent this seems to be due to the thermostat, which even when working properly, doesn't run hot enough. I'd be interested to see the results if someoe could get their running temperature above 90°C.

For info on monitoring engine temperature see: https://www.the75andztclub.co.uk/forum/showthread.php?t=29584highlight=monitoring+tempera ture

11th March 2009, 11:59	#1
PaulPJ Posted a thing or two Rover 75 2.0 Manual Facelift CDTi Contemporary in Starlight Silver Join Date: Oct 2008 Location: New Forest - Hampshire Posts: 1,003 Thanks: 91 Thanked 42 Times in 42 Posts	Lazy Thermostat on 2.0 CDT with BMW Engine Hi Chaps, I think I might have a lazy thermostat as it takes 5 miles or more to warm up and temp drops a tad when queuing on the M3 (as you do). I have read various threads about changing the thermostat without changing the water pump and that its easier on the BMW engine despite what Mr Haynes says but I dont even know where it is on my car. Does anyone have pictures of how to change it or can someone clever person do a 'How to'. Bring back the crossflow engine, atleast you knew where everything was and could do almost everything with any old tool. Paul

30th March 2009, 10:13	#8
shakennstirred Gets stuck in Rover 75 ConnSE Join Date: Aug 2007 Location: long eaton/Nottingham Posts: 580 Thanks: 0 Thanked 0 Times in 0 Posts	the BMW engine is very efficient and will cool a little if on tickover 5 miles to warm up isn't bad depending on outside temp __________________ Due to government cutbacks, the light at the end of the tunnel has been switched off “You know, somebody actually complimented me on my driving today. They left a little note on the windscreen, it said 'Parking Fine.'” ----------------------------------- British racing green Harman kardon stereo upgrade//SYNERGY TUNING MODULE/EGR bypass/intake mod [SIGPIC][/SIGPIC]

11th March 2009, 12:20	#2
Evansabove Loves to post Rover 75 CDT Conn SE Join Date: Mar 2008 Location: Bournemouth Posts: 272 Thanks: 1 Thanked 6 Times in 6 Posts	Paul, I had the same symptoms and got a new thermostat fitted but the old one was full of "crud" which stopped it closing properly. A good flush out of the cooling system may cure it. My garage said it was difficult and had to take the water pump off and being a friend I believe him. As to the slow warm up, diesel engines are so efficient they take linger to warm up hence the need for a fuel burning heater for the cold weather. I drive through the forest from Bournemouth each day and it can easily take 5 miles before I'm up to temperature. HTH John

11th March 2009, 12:29	#3
PaulPJ Posted a thing or two Rover 75 2.0 Manual Facelift CDTi Contemporary in Starlight Silver Join Date: Oct 2008 Location: New Forest - Hampshire Posts: 1,003 Thanks: 91 Thanked 42 Times in 42 Posts	Hi John, thanks for that. Is it easy to flush out and refill engine? I worry about it because of airlocks and damage to Head Gasket etc etc. If it's something that is easy to do I will get a gallon of OAT and do it when I have a spare weekend. Thanks Paul

11th March 2009, 13:17	#4
steve107 Loves to post 75 cdt tourer diesel Join Date: Jun 2008 Location: swinton rotherham Posts: 492 Thanks: 0 Thanked 0 Times in 0 Posts	i had mine changed at local garage .they did not take water pump off .take drivers side top mounting bracket jack up .sorry take enginre cover plus air filter off.it took the garage about 1.30 hour. charged me £40 to fit .thermo cost£37 from rimmers .its not hard just figerley .

11th March 2009, 17:23	#5
Livermpj Loves to post Rover 75 CDT Club saloon Join Date: Nov 2006 Location: Nottingham Posts: 280 Thanks: 0 Thanked 3 Times in 2 Posts	Hi Paul, Coolant change on the CDT is easy peasy, IIRC there's only 1 bleed point (above the FBH unit). Not sure about the crud theory, mine's 8 years old and clean as a whistle. In theory the OAT should prevent corrosion and sludge formation. I've only changed the coolant once (at 4 years), due again this spring. It's vital you use OAT or a compatible substitute, I palyed safe and stuck with MGR OAT (Orange) - it's not expensive. hth, Pete.

12th March 2009, 07:28	#6
PaulPJ Posted a thing or two Rover 75 2.0 Manual Facelift CDTi Contemporary in Starlight Silver Join Date: Oct 2008 Location: New Forest - Hampshire Posts: 1,003 Thanks: 91 Thanked 42 Times in 42 Posts	Hi Pete, thanks for that. The thermostat seems to be behaving now so maybe it is just me. I think the car is due a coolant change soon so now know its easy I will do it come the warmer weather. Thanks again. Paul

30th March 2009, 07:13	#7
skyrise Newbie none atm Join Date: Feb 2009 Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	Hi ya... My first post... and its a question like this one.. I have a 6 mile drive to work in the morning and my car got just over 1/4 warm.. is this about right for the CDT? it was 0.5 oC out side :\

30th March 2009, 10:40	#9
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,752 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	A more meaningful idea on how the system performs is to use the diagnostics mode to provide the engine temperature in degrees Centigrade. The temperature gauge is relatively meaningless other than indicating that a minimum coolant temperature of 75°C has been reached.This is the temperature when the needle first touches the 9 o'clock (normal) marker. Beyond that, little information can be got from it. Remember that internal combustion engines run at their most efficient in the 95-100°C area, so the longer it takes to reach this band, the more fuel will be consumed. An engine running at too low a temperature may also suffer more wear. From my readings, the diesels rarely run in the optimal temperature band and are typically running too cool. To a large extent this seems to be due to the thermostat, which even when working properly, doesn't run hot enough. I'd be interested to see the results if someoe could get their running temperature above 90°C. For info on monitoring engine temperature see: https://www.the75andztclub.co.uk/forum/showthread.php?t=29584highlight=monitoring+tempera ture