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MG MGF Technical - Replacing coolant

OK, thanks to those who replied to my earlier thread about sourcing a radiator - it's now ordered and I'll also check the underbody pipes when I'm fitting it.

As a new query, who can give me the best way to now replace the coolant? The system will obviously be fairly empty when I fit a new radiator, so I'll refill it with the correct 50/50 coolant ratio, but I want to avoid any airblocks etc.

So, once again, whats the best way to refill it?

Thanks in advance.




D Forber

It would be a good opportunity to change the coolant to OAT spec (Pink/Orange colour). If you have the old green stuff and do decide to change make sure you flush all the old out first - you MUST NOT mix them.

When re-filling use the 3 bleed points to ensure that there is no air whatsoever left in the system.

See Rob Bells website for the procedure.

http://www.mgf.ultimatemg.com/group2/coolant/coolant_bleed_procedure.htm

HTH

Steve

Steve P

stick with the colour that it started with

Also make sure that you bleed the system several times to get it right!

If you don't get the system completely bled you may be on the way to the famous HGF

Neil

MG Rover recommend vacuum filling for the MG TF
transam

I bled all 3 points 3 times last weekend after fitting the new ally radiator.... ive already started saving for the impending HGF that will follow :-(
D Jamieson

>>>> stick with the colour that it started with <<<<

Providing that ALL the old coolant is thoroughly flushed out, I (and Mike Satur, who did my coolant system refurbishment work 9 months ago) didn't envisage any adverse affects in upgrading to OAT on my 98' F.

As a further suggestion, fit a low water level sensor kit, well worth the £90 for peace of mind.
Steve P

Hi,all
The bleeding does need to be done properly and re done a few times to be sure all the air locks have gone.
Easy job which i did after the hg went last year and i bled the system after the garage got the car back to me, I needn,t have bothered as they had done it properly and i got bugger all air out.
But.......does the jiggle valve not get rid of small air locks?? or am i miss read/informed.
Mel..
m e johnson

Somewhere in the archives Roger Parker writes that the jiggle valve can get gummed up and needs to be cleaned out to keep it working. I guess the best time to do this would be when refilling the system.

Chris
Chris

I think you are right Mel,
a badly bled system 'should' be automatically purged by the juggle valve, well the critical head end should be anyway (and bleeding the rad is a formality).
I believe that HGF attributed to incorrect/incomplete bleeding would be better blamed on a faulty jiggle valve. since if this works properly you always keep a head full of water.



J LEWIS

There is a lot in what Neil say´s about "stick with the colour it started with". The old type of coolant forms one type of protective layer taken from the different metals in the cooling system. Even after a 100% flush there will be a process with the new OAT that breakes down this protecting layer in order to start a new build-up. And the process takes this from the metals involved = thinner metal wherever there are junctions,welds,seals etc. So for a fairly old car I would not change for anything like OAT-coolants,even if they are handy with their "lifetime" protection./Carl
Carl Blom

It is called 'passivation of the substrate', and is the best protection your cooling system can get. It is best to have the smallest number of different valency metals involved. The F has mild steel, stainless steel, copper and aluminium. Oh dear!
C.R.B. Simeon

Hi,what is the standard way of emptying the coolant ? I take it that either hose be unclipped at the junction between the steel 40mm pipe, and the rear, "to the engine," rubber hose.Also, is there a clear location photo of the jiggle valve ?.Thanks, Bob.
rb wadwsorth

It is the right location to drain the colant.

Check this one for some pics of the jiggle valve. (scroll down)
http://www.mgfcar.de/bleed/index.htm
Dieter

Thanks Dieter,I haven,t had my 3 things go wrong yet this week, so as soon as the next one pops up Ill get into it, I might leave the jiggle valve this time though, it looks a bit of a mission for a first timer,, thanks Bob.
rb wadwsorth

This thread was discussed between 02/05/2007 and 11/05/2007

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.