A guide to keep engines Cooler

Frequent coolant checks always vital on most classics

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Engines are at their best when good and hot - and overheating is the bane of many classic cars. Don’t let yours be one of them…

There’s a thin line between an engine up to working temperature and overheating. Typically most classic engines work at their best around 85 Centigrade - not far short of boiling point. So it stands to reason that if the cooling system is not in tip-top shape then it’s easy to hit the red, particularly on newer and neo classics where their water capacity can be measured in thimbles. Due to their age and deterioration, classic cars are the most vulnerable and excessively hot running can do a lot more than have you hot under the collar, usually bonnet up by the roadside. There’s a greater chance of head gasket failure (especially on alloy-headed units) while cars not equipped with hardened valve seats are in danger of valve seat recession. For many enthusiasts, the cooling system is the most unglamorous part of an engine - yet perhaps the most vital. So long as there’s water in the system and it’s not losing it through leaks or internal combustion this doesn’t imply that all is well. Here we answer the most asked questions - plus explode some myths along the way!

• Water Wise
• Check coolant level before each lengthy journey or if the car hasn’t been used for a period of time
• Look for tell-tale signs of leaks - staining from anti-freeze around joints and gaskets are good clues
• Oil in water or vice-versa? Then it could be head gasket woes ahead. A compression test reveals truth
• Losing water, irregular overheating? Could be an air lock in the system that needs to be bled out
• This is typically done by removing a heater return hose with engine running to force air out under load
• Check the hoses for cuts, general ageing and internal collapsing; need to remove to check last point
• Bulging past clips shows age of hose - top hose hardest hit; always replace with quality OE parts
• Check rad cap for aged seal and spring allowing pressure to escape and reduce running temperature
• You can experiment with various pressure caps: higher the poundage the hotter the water will be but don’t go mad here
• Out of tune engine (retarded ignition timing) can cause overheating as can an over weak fuel mixture at higher speeds