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MG Midget and Sprite Technical - Midget 1500

Hi

what anti freeze type is suitable for 1500 midget?

From what I can see at least 3 types exist
oat, oat extended & hybrid oat

I want to send a technical spec to my brother in Norway, so preferably need a tech spec not a brand name.

What is the total coolant capacity & if possible the % required for near arctic conditions -30c

thanks Colin
C Kinsella

I've always just filled a gallon milk jug with a 50/50 blend of antifreeze and water and used that to fill and top up the system as needed. I keep a jug of blend under the workbench in the garage. I generally use the "normal" Prestone etc... whatever's handy. Being an all-iron engine, there's no need to bother with the special stuff that's optimized for iron/ally or all ally engines. As I understand it, my engine's protected to around -34° F.

Cheers,

-:G:-
Gryf Ketcherside

You can also test the coolant for how low it will go, don't exactly know how though.
But its posssible.
I use Glyco shell nowadays because its cheap (for me, we have drums full of it at work) and its a nice blue colour, easy to spot leaks to.
Alex G Matla

There are 2 basic types of coolant:

1. Glycol based (usually green or blue).

2. OAT - Organic Acid Technology (usually sold premixed and pink in colour. Sold in Halfords as well as some Texaco stations).

Glycol based coolants have a life of 2 years whereas OAT has a life of 5 years.

OAT coolant is generally the type used in modern alloy engines because it better resists galvanic interaction at lower concentrations than does glycol.

On an alloy engine glycol has to be run at around 50% concentration to resist galvanic action. At these levels it will (fairly rapidly) rot out rubber pipework (although silicone pipes seem to fare better).

Glycol based coolants are also less efficient at heat transfer than are OAT coolants.


OAT is the coolant of choice for me - we use it in the race Midget.


HOWEVER

OAT and glycol coolants SHOULD NOT be mixed because there will be a chemical interaction between them leading to the build up of acidic salts in the water passages.

If you are planning on replacing glycol with OAT YOU MUST fully flush the system with a 'rad flush' before replacing the coolant.
Deborah Evans

Interesting info, Deborah - so in your experience the OAT coolant is best; advice taken. To what ratio do you mix it with water?

Thanks,

-:G:-
Gryf Ketcherside

I think you need to take into account "Availibility" of OAT...In my neck of the woods I dont see it on the typical conveniant store shelving, (How many times have we had to pay those inflated prices at 2 am 100 miles from home) but then agian im not actively looking for the stuff...in fact I dont see it in the auto parts stores vary often...Im sure they got it, its just not on my rader, like Deb says "They are NOT interchangeable.

Prop...glyco, Its definatly not a pepsi, so sweet dogs & children like drinking it...Prop
Prop

Colin,

A 50% mix of glycol will protect to -34F (-36C). a 70% mix will get you to -84F (-65C). We do have some here stateside that is compatable with either type and the mix is the same.

Deb- I'm surprised they let you run antifreeze in your race cars. Here in our vintage groups, one of the first questions in tech is what do you have in the cooling system.
Tim Michnay

Hi

Thanks for all of the responses.

I need to know the total coolant capacity so I know how much to put in at eg 50%

Thanks Colin
C Kin

"To what ratio do you mix it with water?"

Gryf, I buy it pre-mixed at 50%.

"Deb- I'm surprised they let you run antifreeze in your race cars."

Tim, while many racers run straight water, I prefer to run a coolant mix because it has better a heat transfer capacity (aside from stopping any salts in water solidifying out - I've seen any number of motors with furred up waterways), it also acts as a better lube/coolant for the electronic water pump that we run. Obviously we are not bothered about its freeze resistance qualities!

I take your point about coolant in race cars (and the spillage(s) of) but the RAC MSA (our governing body for racing) takes the view that, while a coolant spillage is bad, an oil spillage is far worse.

Colin, the coolant capacity of a 1500 Midget (inc water heater matrix) is 12 Imperial Pints.
Deborah Evans

Deborah-
On what basis do you say "...glycol...around 50% concentration to resist galvanic action. At these levels it will (fairly rapidly) rot out rubber pipework"?

I ask because I have a lot of things around here with hose up to 30 years old or more that have always had 50% glycol in them - no problems at all. I have seen some hoses turn to mush in short order, but that's clearly the hose and not the coolant to blame. Mostly British hoses made as aftermarket I might add! They go bad on the shelf or on cars sitting with no coolant in them.

FRM
FR Millmore

FRM,

My speciality are Coventry Climax race engines, which I have been dealing with, off and on, for the last 20+ years.

As you may be aware these are (in racing guise) fully wet linered, aluminium alloy, single OHC motors.

The (steel) liners in these engines lie almost fully submersed in coolant - the engine block being (effectively) a water jacket.

From personal experience I found the only way to prevent electrolytic action between the steel liners, Wills Rings, and alloy block / head was (in the old days) to run a coolant at a minimum 50% concentration of ethylene glycol.

Indeed, Coventry Climax themselves recommended this. Furthermore, the derivative of the FWM motor as fitted to the Hillman Imp (semi wet liner) suffered in its early days from head gasket problems. Aside from the water pump design (as well as the early less than stiff blocks), one of the major causes of failure was electrolytic action in the waterways such that Rootes themselves also recommended a 50% coolant mix.

While running such a coolant concentration on the race cars I found that the rubber hoses rotted out fairly quickly such that we would change all the hoses every 2 seasons. It may be down to poor hoses as you say, but discussions with a racing friend who is an Honours Chemist pointed towards the problem being (at least partly) down to the aggressive nature of the glycol. From what I can ascertain the problem is worse in modern rubbers because (in Europe at least and owing to European regulations the equivalent of your EPA) they are weaker than the original fitments.

Modern silicone based hoses (such as 'Samco' and the like) don't seem to suffer this problem.


Deborah Evans

Deborah -
I've run 50% in everything all my life, for the reasons you mentioned. Right now I have a Dodge truck and a bunch of Mazdas, all of which appear to have their original factory hoses, and they are all 15-20years old. Also a Magnette ZB that was rebuilt in 1980, maybe with new hoses, maybe not. Seems unlikely that these companies are making worse hoses for UK and EU, we couldn't be that lucky here!
All bringing us to the never ending question - why is all replacement rubber for British cars so awful? The Mazdas and the Dodge still have all their OE brake hoses, suspension bushes etc - all good, no cracking or wear out. I recall that when I was doing a lot of daily British work in the 60's & 70s and there were still dealers here, we finally started buying replacement rubber from the dealers instead of aftermarket - much better.

FRM
FR Millmore

This thread was discussed between 22/11/2009 and 05/12/2009

MG Midget and Sprite Technical index

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