Reason 1: Appropriate Care
This is a rare issue and should be a simple one to fix depending on which model you have. The older Astons will suffer from poor cooling if they haven’t been that well cared for. The coolant fluid circulating the radiator at the front will become less and less efficient as time goes by. If they haven’t been flushed through over the years you can imagine the build up internally to prevent the free flow of clean treated water. The shape of the radiators will change too. Years of hot and cold temperatures mean they expand and contract each time they are used, eventually the will become miss shaped and perhaps bow slightly at the bottom. Again this leads to poor efficiency.
The more modern Vantages and DB9’s will only suffer from radiator damage, perhaps a stone has gone through the radiator? The early DB9 cars that have high mileage will suffer from the radiators going out of shape and they will eventually crack and fall apart.
Reason 2: Cooling Fans Must Operate Correctly
The cooling fans must operate correctly. The older classic Astons may have just one fan connected to a pulley on the engine block. These are poor and rarely work well enough in the summer. A popular addition is a secondary electric fan at the front of the radiator that operates on a thermostat switch. When we restored our DB5 this was an essential modification and it has worked perfectly. The more modern Vantages and V12 DB9 models have a fan pack which consists of two independent fans. If one of these fails you will notice the temperature gauge rise but in the summer heat it will not cope. The airflow must be constant to keep your engine at the correct temperature, at slow speeds i.e. through town you need fans. Overheating is the last thing you want it can cause serious damage to the engine.
Reason 3: Failing Thermostat
The thermostats can also fail. Sometimes they fail open which means the flow of coolant around the engine can be too much and getting the engine to temperature can take longer. In a cold climate it’s essential your engine gets to temperature as soon as possible for example, so an open thermostat will cause problems with the engines cold start. If the thermostat fails closed then it will have the opposite effect and not enough coolant is circulating quickly enough to keep the engine cool. Thermostats are an easy fix and usually located at the front and top of most engines.
The worst case scenario is you have a major engine issue. This is normally a head gasket failure where the coolant escapes internally and is burnt through the exhaust system and sometimes the coolant can mix with the oil. Take the oil cap from the cylinder head and check for emulsification, this is when oil and water mix it leaves a creamy consistency. Not good. This will require further investigation.
Speak to our Aston Martin specialists about your car if you think you have a problem. We are always happy to help.
Written & Reviewed by John McGurk, Director, in January 2024.