rover 75 diesel cooling system. - MG-Rover.org Forums

Reply
 
LinkBack Thread Tools Rate Thread Display Modes
post #1 of 43 (permalink) Old 22-02-2011, 06:10 Thread Starter
Registered User
 
Join Date: Feb 2011
Location: Eston North Yorkshire
Car: 1953 MG TD
Posts: 35
rover 75 diesel cooling system.

Hi Good morming. can anybody tell me how the cooling system works. ie water from the bottom hose goes to the pump, normally water from the thermostat goes to the top of the rad, but it doesnt seem to do this on the 75 cheers Ian
crusaderxvx is offline  
Sponsored Links
Advertisement
 
post #2 of 43 (permalink) Old 22-02-2011, 12:22
Registered User
 
Join Date: Sep 2006
Car: 2004 Facelift 75 Connoisseur 1.8 turbo with DD Pack. And remember, the troof is out there.
Posts: 9,996
The cooling principle in the diesel is the same as any other engine. The physical layout may look different, but coolant flow is basically the same.

The flow from the head/thermostat goes to the radiator top through the large upper (tapered) hose. Several members have inserted an inline stat within this hose to improve (increase) the running temperature.

TC
T-Cut is offline  
post #3 of 43 (permalink) Old 22-02-2011, 15:25
Registered User
 
Join Date: Jul 2007
Location: Provence
Car: Rover 75 CDT
Posts: 1,234
Hi,

a little diagram to see how it works:



Mike

Last edited by FrenchMike; 22-02-2011 at 15:35.
FrenchMike is offline  
post #4 of 43 (permalink) Old 22-02-2011, 16:45 Thread Starter
Registered User
 
Join Date: Feb 2011
Location: Eston North Yorkshire
Car: 1953 MG TD
Posts: 35
Hi Mike thanks for the diagram. do you know where inline stat should be placed? and why the rad and bottom hose stays cold? cheers Ian
crusaderxvx is offline  
post #5 of 43 (permalink) Old 22-02-2011, 16:55
Registered User
 
Join Date: Sep 2006
Car: 2004 Facelift 75 Connoisseur 1.8 turbo with DD Pack. And remember, the troof is out there.
Posts: 9,996
Quote:
Originally Posted by crusaderxvx View Post
Do you know where inline stat should be placed?
Looking at French Mike's image, it goes in the large central hose running from top of engine to top left corner of radiator (as viewed from front).The hose is cut to insert an aluminium housing. I believe an alternative is to use an in-hose type, which presses into the hose (no cutting).

Quote:
why the rad and bottom hose stays cold?
Coolant exiting the bottom of the radiator has normally flowed down through it and is therefore colder than the upper input. With the diesel, the input is often quite cool anyway due to stat failure. Typically 60-70C, which in engine running terms is cool. After passing through the radiator this fluid will be distinctly cold.

TC
T-Cut is offline  
post #6 of 43 (permalink) Old 22-02-2011, 17:18 Thread Starter
Registered User
 
Join Date: Feb 2011
Location: Eston North Yorkshire
Car: 1953 MG TD
Posts: 35
Quote:
Originally Posted by T-Cut View Post
Looking at French Mike's image, it goes in the large central hose running from top of engine to top left corner of radiator (as viewed from front).The hose is cut to insert an aluminium housing. I believe an alternative is to use an in-hose type, which presses into the hose (no cutting).

Coolant exiting the bottom of the radiator has normally flowed down through it and is therefore colder than the upper input. With the diesel, the input is often quite cool anyway due to stat failure. Typically 60-70C, which in engine running terms is cool. After passing through the radiator this fluid will be distinctly cold.

TC
Hi TC thanks for the input cheers Ian
crusaderxvx is offline  
post #7 of 43 (permalink) Old 24-02-2011, 04:49 Thread Starter
Registered User
 
Join Date: Feb 2011
Location: Eston North Yorkshire
Car: 1953 MG TD
Posts: 35
hI. AND THANKS FOR INPUT. on the diesel the thermostat is the other side of the engine, water flows across the head, and exits from the side on its way to top of rad.

does any one know where the coolant is fed to from the filling resevoir, i suspect the engine block?

trying to get as much info as possible on the cooling system. and experimenting with inline thermostats.

objective is to inprove engine and heater operating temp.

also ideal to be able to replace stat if necesary. maybe an in hose stat? as used on some cars.

when i get a workable system, will share for others the results.
cheers Ian
crusaderxvx is offline  
post #8 of 43 (permalink) Old 24-02-2011, 09:37
Registered User
 
Join Date: Sep 2006
Car: 2004 Facelift 75 Connoisseur 1.8 turbo with DD Pack. And remember, the troof is out there.
Posts: 9,996
Quote:
Originally Posted by crusaderxvx View Post
Does any one know where the coolant is fed to from the filling resevoir, I suspect the engine block?
It's all explained in French Mike's image. The header tank isn't part of the circulation loop. It simply ensures that the loops remain flooded by being positioned higher than the engine. Coolant added to the header passes into the system via a T-piece in the heater pipework. Once coolant gets into the coolant flow, it never gets back into the header, other than through temperature expansion or a severe overheat.

TC
T-Cut is offline  
post #9 of 43 (permalink) Old 24-02-2011, 09:46
Registered User
 
Join Date: Feb 2010
Car: Rover 75
Posts: 311
Quote:
Originally Posted by crusaderxvx View Post
objective is to inprove engine and heater operating temp.

also ideal to be able to replace stat if necesary. maybe an in hose stat? as used on some cars.

when i get a workable system, will share for others the results
There already is a workable system that fits into the top hose - ranging from a few pounds (a Renault in-hose thermostat) to a spun aluminium housing holding a Chevy thermostat available from an American drag racing suppliers.

All seem to work well. What problem do you think needs solving?
Mintee is offline  
post #10 of 43 (permalink) Old 24-02-2011, 20:39
Registered User
 
Join Date: Mar 2005
Location: Newcastle Upon Tyne
Car: ZT CDTI 135bhp
Posts: 248
Hi.

Just like to say i have just fitted an inline stat from: http://www.specialist-components.co.uk/

and it works a treat.

They have a few listed on ebay, they an't cheap at nearly &£70 (roughly) but it takes 15 mins to fit and top the coolant back up, as oppssed to the estimated 3-4 hours to replace teh original unit.

and it looks nice aswell, is a nice turned aluminium unit.
Not sure what stat it has inside but im sure its just a universal 88degree unit.
djyare03 is offline  
post #11 of 43 (permalink) Old 24-02-2011, 21:04
Registered User
 
Join Date: Mar 2006
Location: Kent
Car: MGZT+ CDTi 135
Posts: 812
Quote:
Originally Posted by djyare03 View Post
and it looks nice aswell, is a nice turned aluminium unit.
Not sure what stat it has inside but im sure its just a universal 88degree unit.
It's a 90c stat from a Chevrolet.

I had one, but never got chance to fit it. My engine died (not related to the stat or temp) and I had a replacement fitted, so I had them fit a brand new OEM stat while the engine was out. Sold my Specialist Components stat to another 75/ZT owner.
calibrax is offline  
post #12 of 43 (permalink) Old 25-02-2011, 07:16
Registered User
 
Join Date: Feb 2010
Car: Rover 75
Posts: 311
Quote:
Originally Posted by calibrax View Post
It's a 90c stat from a Chevrolet.
Are the Specialist Components supplying Chevy stats now? I thought they came with some shoddy 'Mini' 88°C ones with some random (and pointless) hole drilled in them?
Mintee is offline  
post #13 of 43 (permalink) Old 25-02-2011, 10:06
Registered User
 
Join Date: Apr 2008
Location: Thornbury
Car: Rover 75
Posts: 28
Quote:
Originally Posted by Mintee View Post
Are the Specialist Components supplying Chevy stats now? I thought they came with some shoddy 'Mini' 88°C ones with some random (and pointless) hole drilled in them?
I fitted a Specialist Components inline stat a couple of weeks ago, it came with an 88°C stat without any holes drilled in it. So far all works well with engine temp cycling between 86°C and 96°C as the stat opens and closes. Not sure if its a Mini stat or not. The car (without a FBH) still takes a good 7 miles plus to reach 88°C which is a great improvement on never going above 67°C during the previous couple of months.
Mike123 is offline  
post #14 of 43 (permalink) Old 25-02-2011, 11:09
Registered User
 
Join Date: Feb 2010
Car: Rover 75
Posts: 311
Quote:
Originally Posted by Mike123 View Post
I fitted a Specialist Components inline stat a couple of weeks ago, it came with an 88°C stat without any holes drilled in it.
Why did some have holes drilled in them? That has never been answered has it?
Quote:
Originally Posted by Mike123 View Post
Not sure if its a Mini stat or not.
I got idea it has a Mini thermostat in from here.
Mintee is offline  
post #15 of 43 (permalink) Old 25-02-2011, 11:20
Registered User
 
Join Date: Mar 2006
Location: Kent
Car: MGZT+ CDTi 135
Posts: 812
Quote:
Originally Posted by Mintee View Post
Are the Specialist Components supplying Chevy stats now? I thought they came with some shoddy 'Mini' 88°C ones with some random (and pointless) hole drilled in them?
No, you're right... sorry wasn't thinking straight. Mine did have a hole drilled in it, but I had swapped it over for a 91c QTH-107 stat.
calibrax is offline  
post #16 of 43 (permalink) Old 25-02-2011, 11:30
Registered User
 
Join Date: Apr 2008
Location: Thornbury
Car: Rover 75
Posts: 28
[QUOTE=Mintee;4298644]Why did some have holes drilled in them? That has never been answered has it?

I think there was a concern that coolant would not wash over the wax filled sensor that operates the thermostat but it was later found that coolant leaked past (by design?) anyway so the drilled hole was slowing/preventing warm up as too much coolant was entering the radiator before the thermostat opens.
Mike123 is offline  
post #17 of 43 (permalink) Old 25-02-2011, 11:35
Registered User
 
Join Date: Apr 2008
Location: Thornbury
Car: Rover 75
Posts: 28
Quote:
Originally Posted by calibrax View Post
No, you're right... sorry wasn't thinking straight. Mine did have a hole drilled in it, but I had swapped it over for a 91c QTH-107 stat.
What temperatures are you getting using 91c QTH-107 stat ?
Mike123 is offline  
post #18 of 43 (permalink) Old 25-02-2011, 15:22
Registered User
 
Join Date: Nov 2008
Location: Scredington City South-East, Lincolnshire
Car: 75 CDT Tourer Conn SE
Posts: 776
I've yet to fit it, but I'm going to to use a 92C Opel unit, as it's the highest temp I could find
RoverInTheWoods is offline  
post #19 of 43 (permalink) Old 25-02-2011, 18:53
Registered User
 
Join Date: Mar 2006
Location: Kent
Car: MGZT+ CDTi 135
Posts: 812
Quote:
Originally Posted by Mike123 View Post
What temperatures are you getting using 91c QTH-107 stat ?
Like I said above, I never fitted it - as my engine was taken out of the car, I had the OEM thermostat replaced instead, and sold the Specialist Components housing.
calibrax is offline  
post #20 of 43 (permalink) Old 25-02-2011, 21:21
Registered User
 
Join Date: Apr 2008
Location: Thornbury
Car: Rover 75
Posts: 28
Quote:
Originally Posted by RoverInTheWoods View Post
I've yet to fit it, but I'm going to to use a 92C Opel unit, as it's the highest temp I could find
What is the advantage of a 92°C thermostat ? What running temp are you hoping for ?
Mike123 is offline  
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the MG-Rover.org Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes Rate This Thread
Linear Mode Linear Mode
Rate This Thread:



Similar Threads
Thread Thread Starter Forum Replies Last Post
How refill cooling system rover 75 cdt? bergjoce MG ZT / Rover 75 (Sponsored by Rimmer Bros) 4 13-03-2011 12:25
420 diesel cooling system bleed screw lackofgrip MG ZS / Rover 45 & 400 29 19-11-2010 15:12
75 1.8 cooling system Dean MG ZT / Rover 75 (Sponsored by Rimmer Bros) 4 03-12-2006 20:59
Cooling System Bleed Pipe - 1995 218 Diesel Turbo TD_218 Wanted 3 22-02-2006 20:52
Rover 25 45 or 75 complete exhaust system for Diesel markmediaLTD Wanted 1 31-05-2004 17:36

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome