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MG MGF Technical - HGF & Coolant

I wish I never found this site. Now I'm condemned for all times to paranoidly drive around in what feels a ticking timebomb.

Of course I'm talking about the HGF-thing and I'm trying to take all the advices into account to prevent the dreaded HGF. I'm even more careful with a cold MGF-engine than with my Norton bike from '74!!

But on the other hand, the car is performing perfectly for me so far, (NOTHING wrong) and the real interesting question: What percentage of the MGF's have HGF, and are there signs of improvement (HGF occuring only on earlier MGFs or are the 1999-2001 MGFs just as vulnerable?). Has rover never made any official comment on this AT ALL???

Anyway, the question is: I want to fill up the coolant, because it's slightly under the seal of the tank, but I want to add the right stuff. The handbook says it can have any coolant based on ethelyne-glycol (50%), but when I look in the shops I can find amber, blue, red and purple coolants. I'm sure thats something different than the green stuff in the MGF, or doesn't the color say anything and can it be mixed without problems? Furthermore, lots of coolants are already mixed, but it doesn't say anything on the percentage, only the minumum temperature (-21, -33 celcius etc.) And if I have to mix it myself, do I have to use deminiralised water? Normally I wouldn't ask such questions and just poor it in, but now I'm a little reluctant. Please tell me I don't have to go to the dealer to get the right liquid????

Greetings, Bram.

Greetings, fellow paranoid! How far below the seam is it, and has it dropped at all? If it's just a cm or so, and it's not dropping, perhaps best to leave it?

As far as new F's getting HGF, I'm on 3K at the moment, so I'll tell you my opinion in three years or so.
David Bainbridge

Hi Bram, dont know where to get the coolant, Tony might know, he lives in Utrecht as well. I'll ask him.
Where are you? Drop us a line. We also have a social event on the 7th July.

There are actually 2 types of coolant (there may be 3, but I don't know that the third has been deployed in the F...)

I know that "older" F's use Unipart Super 2. Its is yellowy green in colour. (I just bought 3 litres of it from the Rover dealer - 8ish!)

Newer cars use, I believe, a blue solution. No details of the type, I'm afraid.

The third type is pink.

Its imperative (I gather) that you get the right sort, and don't mix them (to the extent of thorough cleaning of jugs etc).

I think to get the "right stuff" you'll need to visit Rover, though some factors may do Unipart. Its sold in 1L containers...


Just have been to my local MG-Rover Dealer...

As I ask to the coolant level, they see that it was a little bit low...

Mine is pink color...

And They fill in with some Blue coolant... They said the rover car use Blue one and it's pretty the same thing... So mix them is ok

Still beleave my MG garage...


I wouldn't mix and match antifreeze- whilst the ethylene glycol content maybe the same, who knows what chemical reactions could occur between the other contents of the corrosion inhibitors etc...

Rover use Unipart Super3 antifreeze (according to my handbook, and the dealership that I bought a few litres from). This is applicable with all Mk1 MGFs.

More recent MGFs are filled with a different antifreeze that should under no circumstances be mixed with ethylene glycol based antifreezes... These cars have a label on the coolant cap I believe- so do check.

Click on the HGF link for regular coolant checks advice, and details of the information Dieter has collated on coolant system bleeding...

Rob Bell

New MGF uses Havoline extened life coolant XLC mixed 50/50. I have bought some from a local TEXACO filling station it states on the container that it gives 5 year/150,000 protection.It says can be mixed with other antifreeze/coolants but doing this does not give full 5 year protection. MG say coolant should be changed every 4 years regardless of mileage.

Bram, it's not really the type of coolant which can destroy your HG, it's the way it was put into & bled out of the cooling circuitry. Airbubbles create hotspots, hotspots create HGFs. MGFs are a torture to bleed correctly since the coolant circuit is just too long for being effective. You need to hang the car with its nose on the ceiling to have proper bleeding... which dealer will do that? ;)

Other remarks:

>What percentage of the MGF's have HGF

Whatever I say they'll jump on it and say it's wrong, so my diplomatic reply is "above average of modern cars"

>and are there signs of improvement

Since it's a Rover, no!

>Has rover never made any official comment
>on this AT ALL???

"HGFs are always due to PILOT ERROR"

Unofficially, a high Rover exec (at a BMW garage!) told me once "We know that the MGF is a problem child, esp. with those HGFs". I nearly fell on my back when the guy said that, moreover not knowing who he was talking to! Need I say more?


You only need to add a little coolant so just use clean water. Demineralised water is a good idea if the tap water in your area is hard. The MGF uses a 50% mixture of water and antifreeze so given that the whole system contains 10,5 litres in total, adding even 1 litre of water between coolant changes will bring the mixture to 45% antifreeze content which doesn't really make any difference. It is certaintly better than mixing types of antifreeze that maybe incompatible.

Spyros Papageorghiou

As Dirk says the percentage of HGFs is above the norm - however if we have to be technically correct when he replies 'Since its a Rover NO' - the HGF is in the engine which is not Rover that is Powertrain which is still a part of the BMW Group of companies.

MGR want to take over Powertrain and I know negotiations are in place but until such a time as MGR own Powertrain there is nothing they (MGR) can do to rectify the problem and during the five years that Rover was a part of the BMW group BMW did not see it as a priority or a problem IMHO.

Ted Newman

Just top it up with water, we are talking only a small amount of fluid here. It will all be replaced at a service. This is unless you are losing a lot of coolant, in which case you have a problem and no amount of topping up will fix it.

If you can find Water Wetter or Coolboost additives, top it up with one of these and it will improve the efficiency of your cooling system and further reduce the running temperatures.

I have only had coolant changed by dealers so you local Rover dealer should be able to supply the recommended antifreeze. This should only really be required for a full bleed and refill, or when your car is loasing a lot of water. In this case, as stated above you would have problem that would no doubt require the coolant sytem refilled anyway.

Now now, Ted, a bit of a technicality here, so the standard tyres are not MG's fault, but Goodyear's and the Hyragas is not MG's fault it is Dunlop's fault. Let's see now, crossmember and shock mounts, Mayflower? Dumping the HGF blame on BMW is going a little far I think.

BMW can only be blamed for not understanding what they had taken over and is really only a management problem. I think it was more neglect than anything else. I do not believe in the conspiricy theory. MG/Rover are not really that much of a threat to BMW's core market. I doubt they will lose too many sales world wide, maybe in the UK, a few.

Dirk was very nice here, great to have the real Dirk back, welcome. My theory is that most HGF occurences were caused by lousy dealers not being able to bleed and refill the cooling system correctly, so I would Blame many MG dealers for the majority of HGFs and nobody else.
Tony Smith

Actually, I'd agree with Ted that body faults are the fault of Mayflower, engine problems the responsibility of Powertrain and so forth Tony.


MG Rover has ultimate responsibility for the whole vehicle, and should ensure that its sub contractors build the components of the car to the specifications and quality demanded.

All are culpable to criticism.
Rob Bell

I'm not 100% that all the engine problems are Powertrain's fault.

If the same engines in other cars (other Rovers, Elises,...) don't have such a high incidence of problems, then some of the blame comes back to Rover for the design of the cooling system and engine bay environment in the F.


>MG Rover has ultimate responsibility for the whole vehicle, and should ensure that it's sub-contractors build the components of the car to the specifications and quality demanded.

My point exactly...
Tony Smith

>>>My theory is that most HGF occurences were caused by lousy dealers not being able to bleed and refill the cooling system correctly, so I would Blame many MG dealers for the majority of HGFs and nobody else.<<<

Well, then it's the car manufacturer's duty (Rover's duty) not to use a cooling system which induces way too much dealers to screw up on bleeding it. If the design is prone to mistakes made by those supposed to be in the know how to operate it, then simply don't use it, but use another system. No kudoes to Rover.

-- Luc --

This thread was discussed between 13/06/2001 and 15/06/2001

MG MGF Technical index

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