Antifreeze for your P4

Traditional blue Ethylene Glycol is a toxic but highly effective antifreeze; it contains silicates as an inhibitor to help prevent corrosion in engines with mixed metals in their make-up. Bluecol is a well-known brand name and is declared suitable for 'classic cars' on their company website. Several companies on eBay sell blue Ethylene Glycol antifreeze in bulk 20 litre containers reducing the long term cost. Typically the effectiveness of blue antifreeze will start to drop off after a couple years’ use and the coolant should be changed for new, more of an issue where extreme cold temperatures are encountered.

A note on the readily available red/orange OAT (Organic Acid Technology) anti-freeze, OAT antifreezes have been accused of destroying seals, gaskets and lead based materials and causing a great deal of damage in 'old' engines. For this reason, the manufacturers do not recommend their use in historic vehicles.

Should you use regular tap water when mixing coolant and water together? Ideally no, you should use distilled water/clean rain water or better yet, de-ionized water. The reason for this is that tap water has all manner of chemicals, minerals and other pollutants that can form deposits inside the radiator and the cooling system passages of your engine, and over a long period of time they can contribute to over-heating.

In normal operating temperatures a mix of 1:2 blue Ethylene Glycol antifreeze to clean rain water is sufficient; in colder countries a 1:1 mix may be preferable. Mixture ratios and the corresponding below zero temperature protection levels should be labelled on the product itself.

Much attention has been given to Waterless Glycol coolant such as Evans Waterless in recent years, here are some notes on said coolant:

Let’s state the obvious: waterless coolant is different from regular coolant because there is no water in it. Waterless coolant is made up of the same basic glycols as regular coolant but operates much differently without the water.

The boiling point of waterless coolant is 375 degrees Fahrenheit and it freezes at -40 degrees Fahrenheit. Instead of expanding when frozen, like water does, without the water, the coolant actually decreases in volume.

Waterless coolant additives do not fall out of solution as with regular coolant. Stable additives are added to the waterless coolant so the coolant never goes bad, whether it is used or still sitting in the container, so it never has to be replaced.

Waterless coolant doesn’t build vapour pressure in the system. There is moderate pressure build-up from a 7% fluid expansion, so if you open the radiator cap when the coolant is hot, it may spill out a few tablespoons, but it doesn’t have the vapour pressure that can blow up in your face like regular coolant. It must be said that if there is residual water still in the system (over 3% to 5&), vapour pressure will build.

If you have waterless coolant in your system and it is low and you didn’t bring extra waterless coolant on your journey, don’t worry. You can add water or regular coolant to the system with no issues. With water added, it will behave just like regular coolant but lose the waterless-coolant benefits, though then making for an expensive drain and refill once home.

Many waterless coolants, including Evans’ old formula, would corrode with an addition of only 3% water. A waterless coolant that meets the ASTM (American Society for Testing and Materials) standards can have up to 10% water and still retain its anti-corrosion properties. Evans Coolant will still protect with up to 60% water. It can’t, however, retain its lifetime use with water added and will go bad within a few years.

When you get vapour in the cylinder head passages, the vapour pushes the liquid away from the metal in that spot, which can raise the metal’s temperature considerably. This can cause detonation, warped heads and blown head gaskets. These hot spots don’t develop with waterless coolant, because the waterless liquid will always be in contact with the metal to cool it down.

To ensure you get the full benefits of waterless coolant, the cooling system must be completely drained or have a maximum of only 3% water. Not an easy thing to achieve, likely requiring removal of the water pump and use of a compressed air line gun to blast out all the waterways.

Do I use it? No, it’s seriously expensive! But if I win the lottery I will convert all my cars to it...

This article was kindly prepared by Guild member Ian Portsmore for the Overdrive magazine and is included here for the members who have joined the Guild after publication.

By trade, Ian is an aerospace engine and airframe technician with most of his career spent in either aerospace or top level motorsport. For the last 14 years he has worked as a Technical Inspector for Rolls Royce Aerospace (large civil engines). His personal work and interests have involved engine building and tuning, and P4 rescue! Of particular interest to Ian over the last 30 years has been engines, engine theory, engine tuning, and engine oils and their development.

Ian is best known in the Guild as the owner and creator of CAS 232, the outwardly standard P4 powered by a period Ford V8, with much engineering revisions to transmission, suspension, brakes and many other parts to handle the power and performance.


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