Vauxhall astra drives for about 5miles then goes into limp mode,rev counter drops and radiator warning light appears along with the spanner in the engine warning. leave for an hour then it drives ok for...
Unless you want to risk very expensive engine damage for what is likely to be a relatively simple and cheap repair, then do not drive the car again until you have fixed the fault.
Likely causes are as follows:-
1. A failed temperature sender. You haven't stated the year, model and engine of your Astra, but on most model it's on the side of the radiator. An easy DIY job, but on some versions the sensor replacement means you must partially drain down the coolant. Total cost around £20 for the part and replacement coolant, around £80 if done professionally in London. Costs are lower away from the South East and major UK cities.
2. A failed water pump. If it's not circulating coolant then the engine overheats. If the pump needs replacing then get the timing belt replaced at the same time as it has to be removed anyway to do the job. One of those jobs where the parts bill is relatively low but the labour charges are fairly high: total cost typically around £300 in London.
3. Blocked coolant channels in the radiator/engine block. This is highly likely if you have just been using water as it causes corrosion. Proper coolant mix not only acts as an antifreeze, but prevents corrosion and enhances the ability of the coolant to carry away waste heat. Requires a drain down, back flush, and refill with the correct coolant mixture. Typical cost around £130 in London.
4. A failed engine cooling fan. Note that if the temperature sensor has failed and it can either send false overheat signals to the engine management system to cause your problem, or it can totally fail and cause genuine overheating by failing to activate the cooling fan. If the fan does not activate when the engine starts getting hot , and the sensor has been replaced, then the fan (or an electrical connection to it) has failed. An easy DIY job, can cost under £30 DIY if you buy a used fan from a breaker's yard, or around £150 if you use new parts and get the job done professionally.
Whatever you choose to do, overheating also commonly causes cylinder head gaskets to fail. Make sure that you get a repair garage to perform a coolant test before anything else. This will instantly determine whether the head gasket has failed. It's an expensive job and starts exactly as for a timing belt/water pump renewal, but then goes further in having the cylinder head removed and then it must be checked for crack/distortion which can add a fair bit or an enormous amount to the job, depending upon what's found and whether a replacement cylinder head is required or just refacing of the existing one. With head gasket replacement it's a false economy not to replace the timing belt and water pump at the same time.even if they seem fine. Getting the coolant test will help you decide whether repairs are worthwhile, as they can cost more than the car is worth.
This list is not exhaustive, but all of the work is within the scope of a competent home mechanic (though if the cylinder head needs attention that part must be sent to an engineering shop).
Jun 28, 2011 |
2001 Volkswagen GTI