Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club General Forum
Register FAQ Image Gallery Members List Calendar Search Today's Posts Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 21st October 2019, 22:24   #11
Steve42
I really should get out more.......
 
Steve42's Avatar
 
Rover 75 v6 2.5 con se

Join Date: Feb 2013
Location: Bedworth
Posts: 2,158
Thanks: 187
Thanked 345 Times in 238 Posts
Default

Quote:
Originally Posted by DMGRS View Post
Just to add - make sure you're running the correct anti-freeze blend all year round - one of the properties of this magic stuff is that it raises the boiling point of the coolant quite significantly.
just got the new cap from you and to be honest I hand not noticed how flat the rings had become on the old one.
Steve42 is offline   Reply With Quote
Old 22nd October 2019, 21:14   #12
T-Cut
This is my second home
 
Rover75 and Mreg Corsa.

Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 20,551
Thanks: 252
Thanked 3,050 Times in 2,492 Posts
Default

Quote:
Originally Posted by DMGRS View Post
Just to add - make sure you're running the correct anti-freeze blend all year round - one of the properties of this magic stuff is that it raises the boiling point of the coolant quite significantly.
It's interesting to put some numbers on this to illustrate how things vary.

These data are at normal atmospheric pressure (1 bar/15psi/100kPa)


Thus all ethylene glycol based coolants have the same boiling point at the same concentration and pressure. That doesn't change whether it's the latest OAT, IAT, HOAT or any of the earlier inorganic acid varieties (phosphates/silicates/borates/ etc, etc.) The various additives constitute perhaps 5% or so and have negligible impact. Nor do they, inter alia, affect the engine running temperature.

The recommended concentration is 50%. If you decide to reduce this to say 30%, then all these numbers reduce as well. So, any coolant containing a 50% EG based antifreeze will boil at around 107C at normal atmospheric pressure (1 bar/15psi). Of course, our cars operate at an elevated pressure, roughly 1.4bar using a '140' type pressure cap. Thus with the vapour pressure restricted to 1.4bar/140kiloPascals/20psi, the boiling point is raised by about 10C to 117C. (This figure is taken from the boiling point curves for aqueous EG solutions at different pressures). Going beyond this point will cause the header tank to vent. Of course, the running temperature isn't controlled by the running pressure. It simply limits it's maximum operating temperature before the coolant starts to boil.

TC

Last edited by T-Cut; 22nd October 2019 at 21:20..
T-Cut is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT +1. The time now is 18:30.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2006-2019, The Rover 75 & MG ZT Owners Club Ltd