All these remarks are covered by the RSR's standard disclaimer.
"The Person raising the question uses the response and/or the advice given at their own risk. Whilst every care is exercised, neither the Rover Sports Register Ltd, nor the individual responding are in any way responsible for any incident involving the response however caused."
Handbooks that I have seen suggest a "Good Quality ethylene glycol based antifreeze with distilled water" Bluecol was recommended for pre-war Rovers and the brand still exists, see BLUECOL 2 YEAR ANTIFREEZE & SUMMER COOLANT -2.5 L. ( The product data sheet is at:_http://bluecol.co.uk/wp-content/uploads/2013/01/pis-005244-150520121.pdf) The cooling system holds about a gallon, and the ideal mixture will depend on the lowest temperature expected. According to the data sheet, 1part anti freeze to 1 part distilled water will protect down to -36 degrees C, 1 part anti freeze to 2 parts water protects down to -17 degrees C. It may be prudent to use additional corrosion inhibitor like Millers extra cool.
The following comments from the FBHVC may help.
" From the FBHVC Website
Technology moves forward and new products are constantly being launched with claims to improved formulations and performance. With the recent bitterly cold weather in January antifreeze has been in the headlines, with some alarming stories which at first seem to be about the well-known tendency of antifreeze to find the tiniest hole and cause leakages – but in these cases it has led to catastrophic engine problems.
Traditional blue ethylene glycol is a toxic but highly effective antifreeze and contains silicates as an inhibitor to help prevent corrosion in an engine with mixed metals in its make-up. Bluecol and Blue Star are well known brand names and both of these are declared suitable for ‘classic cars’ on their company websites. Be aware that there are also low- or no-silicate ethylene glycol formulations (usually red) available which may not be suitable for all engines.
Propylene glycol is another well-known and less toxic antifreeze formula and usually contains silicates but Comma, the main manufacturer, has now discontinued it in favour of an ethylene glycol product containing ‘bittering agents’ to make it less palatable and minimise the risk of accidental poisoning.
Both of the above products use inorganic additive technology (IAT). Recently problems have been reported concerning the use of antifreeze mixtures using organic acid technology (OAT). OAT was introduced in the mid-1990s and the products are biodegradable, recyclable and do not contain either silicates or phosphates and are designed to be longer lasting. However these products do seem to cause problems in older engines; over and above the ability of antifreeze to find the smallest crevice and leak, OAT antifreezes have been accused of destroying seals and gaskets and causing a great deal of damage in ‘old’ engines. For this reason the manufacturers do not recommend their use in historic vehicles. These products are usually coloured red, pink or orange.
The final category is HOAT. These products use hybrid organic acid technology in an ethylene glycol base with some silicates in the formulation alongside the organic corrosion inhibitors. The product is usually coloured green and is not recommended for use in historic vehicles.
The Federation is still researching this problem but our advice at the moment is:
· only use blue coloured IAT antifreeze in historic vehicles;
· only use OAT products (‘advanced’ or ‘long life’antifreeze) if the vehicle used it when new and if specifically directed by the vehicle’s manufacturer;
· never mix different types of antifreeze without thoroughly flushing out the system;
· always replace the coolant within the time scale specified by the antifreeze manufacturer as the corrosion inhibitors break down over time.
In the article in the last newsletter, we said ‘Bluecol and Blue Star are well known brand names and both of these are declared suitable for classic cars‘. Perhaps we should clarify that we were referring to the traditional blue coloured Bluecol – but the company also sell a red coloured Organic Acid Technology (OAT) product suitable only for modern cars, not classics. Even more confusingly, there is also Bluecol U which is marketed as a universal top up and not an antifreeze product with which you would fill the whole tank. The manufacturer has assured us that this is suitable for historic vehicles.
It has also been brought to our attention that Halford’s sell a blue-coloured ‘Advanced’ antifreeze which has a label containing the phrase: ‘Older vehicles can further benefit…’ but on further examination it was discovered that this product does indeed contain OAT and therefore cannot be recommended for historic engines.
Our postbag has also been swelled by correspondence relating to the extremely poisonous nature of ethylene glycol, indeed the Cats’ Protection League has gone so far as to start an on-line petition to highlight the danger to small animals accidentally ingesting tiny quantities of the product. Propylene glycol is much safer and one of our new trade supporters, AAA Solutions Ltd, is about to launch a propylene glycol based antifreeze specifically aimed at historic vehicles.
It does remain a rather confused picture, but the important facts to remember for historic vehicle owners are: use only Inorganic Additive Technology (IAT) products according to the manufacturer’s instructions and take great care with any liquid containing ethylene glycol."
Hope this helps,