Cooling

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Hooray, the sun’s back! However, if summer has got your classic all hot and bothered, here’s how to cool down

If there’s hot weather, and you see a classic brokendown by the roadside, then the chances are that it has overheated – along with its owner! But, this needn’t be the case because after all they didn’t boil over when they were new, did they, so it can only mean poor maintenance. Have a look at your kettle at home and you’ll be horrified at the limescale build up – and it’s the same for engines, over time. Happily, there’s a lot you can do to make your car’s cooling not just as good as new, but even better!

MAINTENANCE

This is the key to reliability. Start with hoses; check they are okay,not ageing and bulging past their clips (which should also be in good order and preferably proper ‘Jubilee’ type affairs and not the nasty wire sort). Just because a hose looks okay, it doesn’t mean that it hasn’t collapsed internally, so remove and check if in doubt. Now, check the rad cap plus its spring and rubber seal – replace it the cap looks past it.

With the engine up to temp, remove the said cap (very carefully) and check that the water is circulating, indicating that the thermostat and water pump are okay; the latter should give a vigorous flow. If this isn’t the case (and it may also mean a blockage) consider replacing both.

An airlock, usually identified by poor heater performance, will also cause overheating. To check, remove the highest positioned heater hose and run the engine; water should gush out at an even rate, but if it stops, then that’s the air bubble causing all the trouble.

It is vital to drain and flush out the system every couple of years and ensure that the antifreeze is changed at the same time. Today’s brews are all-round protecting additives – lowering the icing temperature of water in the winter and raising the Centigrades when hot, to reduce the risk of boiling. Critically, anti-freeze contains a corrosion inhibitor to prevent furring up. Some enthusiasts run a 50 per cent mix of anti-freeze, and change it yearly, to keep trouble at bay; cheap insurance, it has to be said!

A good flush through the system with a hose at the same time, in conjunction with one of the numerous de-scaling additives that are widely available, is sensible. Remove the radiator and play a jet of water through the ‘honeycomb’ rad fins (both sides) to remove a build-up of debris, road muck, dead insects etc (the transverse-mounted rads on Minis suffer badly here).

You’ll be amazed just how much rubbish accumulates!

Thermostats aren’t just an open and shut case; they are constantly operating and so can age and deteriorate. A new ‘stat can work wonders, and you can even change the operating temperature by fitting a ‘winter’ one, which opens at a higher temperature, and so makes the engine run hotter, if desired.

Incidentally, don’t be tempted to run without a ‘stat since, on some engines, it forms part of the circulation route and the lack of the ‘stat upsets the flow, leading to overheating.

Naturally, ensure the fan belt is in good condition and properly tensioned.

Finally, ensure your car’s engine is in good tune. An over weak fuel mixture and/or the ignition timing that’s ‘out’ all cause an engine to run hotter.

IMPROVEMENTS

Why not make yours better than new with an uprated radiator, because it’s the heart of the system? We’re advocates of uprated rads, using larger, more efficient cores from the likes of Radtec and Aaron; we’ve been running a Radtec one for years in our Project Zephyr and never had a moment’s overheating trouble. Radtec, for example, offers two stages of upgrade: Stage One provides up to 25 per cent extra cooling while Stage Two offers 50 per cent.

An electric cooling fan is a wise mod because a standard engine-driven fan is a wasteful device, as it does little at low speeds when the air ram effect is minimal, yet screams blue murder at high revs when you least need it. Revotec has a full range of dedicated kits along with electronic fan controllers (go to http://www.revotec.com) for the majority of classics. If you’re a stickler for originality, have a look at overseas versions of your classic; in many cases they featured items such as larger cooling fans and radiators.

There’s a number of special pour-in coolant additives that claim to make normal water ‘wetter’ and so improve its efficiency, by giving superior surface contact between the coolant and metal surfaces.

At least 10 per cent gain is spoken of, plus it can be mixed with anti-freeze. However, in our view, such additives should be regarded as a little extra help, rather than a total solution to an overheating classic.

Why rely on water when there are better alternatives? Evans Waterless Coolants have a higher point than water and effectively eliminate overheating, boil over and after boil. As there’s no water, there’s no water pressure either to build up and, being waterless, there’s no corrosion and erosion worries for the internals, so is ideal for classics in storage – the product is being used by Beaulieu’s museum.

It’s not cheap, at £100 for a typical large engine, mind (and you’ll need to keep some extra for top ups) but lasts a lifetime. We’re running some in a Jaguar E-type and will report on its progress. The idea is not new, as we have previously run a Vauxhall Viva using a much earlier product from the 1960s called Forlife (from United Lubricants of London) and can certainly vouch for the excellent state in which it kept the waterways.