MG-Rover.org Forums banner
1 - 6 of 6 Posts

·
Registered
mg_tf
Joined
·
36 Posts
Discussion Starter · #1 ·
Can anyone tell what temp the coolant fan should kick in, My TF failed mot because it so say boiled over before they could complete the test. Ive just run the engine it reached 103° and still no fan.
 

·
Registered
mg_tf
Joined
·
448 Posts
From memory mine kicks in at 105 degrees. If yours is boiling at 103 it's not holding pressure and I'd suspect the expansion tank cap. It could also be that the fan isn't working.
 

·
Registered
MG TF
Joined
·
3 Posts
Newby here! Tf cuts in at 104 degrees whereas mgf cuts in at 102.6
Kmaps were able to change mine to cut in at 98 degrees (my choice) so the fan cuts in before it boils if (when!) the coolant cap fails
 

·
Registered
mg_tf
Joined
·
455 Posts
The 102/104 sounds about right in my book. I would have thought that reducing the fan-cut-in to 98 might result in the fan running under normal running conditions - not really what is wanted.
The coolant will not physically boil at 102/104 due to the pressurised cooling system. Water will only boil at 100 degrees C at atmospheric pressure. It will boil (bubble) at lower temperatures if the pressure is below atmospheric, or not until higher temperatures at increased pressures.
 

·
Registered
MG TF
Joined
·
3 Posts
The 102/104 sounds about right in my book. I would have thought that reducing the fan-cut-in to 98 might result in the fan running under normal running conditions - not really what is wanted.
The coolant will not physically boil at 102/104 due to the pressurised cooling system. Water will only boil at 100 degrees C at atmospheric pressure. It will boil (bubble) at lower temperatures if the pressure is below atmospheric, or not until higher temperatures at increased pressures.
Live temperature readings on my phone showed 98 degrees only reached once this summer. That was up a very long welsh hill in 2nd gear on one of the hottest days of the year while stuck behind a lorry.
Pressurised coolant not boiling until 104 degrees would be fine if the coolant caps were reliable.
 
1 - 6 of 6 Posts
Top