How to keep your classics cool

Check radiator fins for damage. Radiators can be replaced or re-cored – often with higher efficiency internals to aid cooling on older engines which is a wise step. There’s even additives to make the coolant ‘wetter’

Water leaks? Tighten and even renew aged spring clips before using a sealant in the system to stop it

Flush and back flush the radiator to rid it of nasties such as slime and rusty deposits. It’s easy to do

Obvious but often overlooked, check that the fan belt is in tip top shape and replace now if in any doubt!

Dedicated flushing agents are available if radiator or engine needs de-scaling; pour in a can before draining

It’s a good idea to hose out the fins (both sides) as it’s amazing how badly they become clogged over time. Use a degreaser here if required. If old a new core is a very wise step

Sludging or a mayonnaise here indicates a failing cylinder head gasket. Have system pressure tested

There’s loads of system additives on the market and are certainly worth a try if your car is overheating

Viscous cooling fans can fail and run so continuously, it won’t hurt car though and they are dear to renew

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Don’t let your car (or your blood) boil over this summer by sorting out that aging cooling system right now!

One of the biggest fears all car owners have is breaking down when out and about and overheating is one of the most commonest problems for us classic car users is overheating. Come on admit it – how many of us carry bottles of water in the boot just in case? According to motoring organisations, cooling system failures is one of the top five breakdown causes but in theory an old classic should be no more susceptible to boiling over than a new car – so long as the engine’s cooling system is well maintained. The trouble is that it isn’t on many oldies. So here’s what you do before the summer season really starts…

Radiator

This is the part that cools the water and so needs to be in tip-top shape. If you can, remove it from the car (it’s simple enough on most front-engined oldies) for inspection and a thorough flush out with a hose including a reverse flush where you go against the natural flow direction. You’ll be amazed by how much gunk will be pushed out! Similarly hosing the honeycomb matrix of dead flies and much will improve its cooling capacity no end, especially on certain front-wheel drive cars like BMC models where it is prone to collect a lot of debris and oil (use a degreaser if necessary). Inspect the rad for split seams, damage andgeneral aging. Replace if suspect; it’s better to do it now than by the roadside on a baking hot Sunday afternoon! And don’t forget the often-overlooked rad cap: look for aged seals and a weakened pressure spring.

Engine block

Much the same applies here; flushing and reverse flushing is a worthwhile job but if you reckon that the waterways are still gummed up then try a special de-scaling agent that’s a simple pour in while the engine can still run. One of the reasons this occurs is that too many owners believe anti-freeze is purely for winter: it isn’t. Sure it keeps the aqua from turning to ice but during normal motoring it also provides a vital anti-corrosion agent plus helps reduce boil-overs. Never skimp on using quality anti-freeze all year round especially if your engine is made from alloy – and change it as and when advised. Again, there are misconceptions here; even though the antifreeze may still keep its properties, the corrosion inhibitor probably won’t. Inspect the core plugs. Any signs of weeping here and you should replace them. They are not expensive but can be awkward to replace due to their location.

Water pump/cooling fan

There are two differingschools of thought concerning water pumps. Some reckon it’s a fit and forget component and only replaced when defective, while others see it as a relatively inexpensive part that’s well worth renewing for peace of mind (especially if you’ve already removed it during a strip down). You can usually tell when a water pump is ready to pack up, as it will either make a lot of rumbling noises, indicating a failing bearings, or if the main seal starts to leak. Another check is to grasp the fan or pulley and feel for excessive movement. Engine-driven cooling fans need no attention, although if you are finding that your engine is running too hot, then you may be able to fit a higher output version – perhaps from an export model – or better still consider fitting an electric cooling fan such as a Kenlowe and gain a faster warm up, less noise and even slight added power (a normal fan set up consumes about 2bhp).

Thermostat/hoses

If the thermostat in your engine has been doing the business for years – replace it. Contrary to popular belief, a defective thermostat doesn’t only make the engine boil like a kettle if it fails to open. If the ‘stat becomes old and gummed up then it may only partially open or be slow to activate. You’d be surprised the difference a shiny new one can make to your car’s cooling system. Hoses are the easiest things to visually check. Aged and perished ones will look it and bulge past their securing clips. A healthy hose should be firm yet supple to press. If soft, then the hose is aged; rock hard then it may well have partially collapsed internally. Even if the hoses are healthy, check that the wire clips aren’t cutting in to the rubber and so cause a small but potentially expensive leak and see that all hose runs are okay.

Air locks

Air locks always get owners hot under the collar but are fairly easy to fix. If you are filling up the cooling system from scratch, turn the car’s heater control to the fully hot position so to make the heater part of the circuit and squeeze the bottom hose as you are topping up. With the engine up to temp, remove the hose that’s at the highest point in the system (usually a heater one). Water will gush out and then stop as the air is being pushed out. When water flows again reconnect the hose and top up accordingly. MGFs require a special technique by the way!