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Kevin, UK Car Mechanic
Category: UK Car
Satisfied Customers: 1978
Experience:  Diagnostic technician at vw /audi specialist
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C220 cdi auto: ***** ***** a Mercedes c220cdi auto it start great

Customer Question

I have a Mercedes c220cdi auto it start great when its cold but when it gets hot it will not start
Submitted: 2 years ago.
Category: UK Car
Expert:  Kevin replied 2 years ago.
Hi I'm Kevin. The most common cause of hot start problem on diesel is an injector that has a slight leak from internal spring . The reason this occurs is when the car warms the diesel gets thinner making it harder for the engine to build fuel pressure when starting this added to an injector that is starting to age and has slight seepage internally means the car cranks for a period before eventually firing into life . The car is fitted with Bosch injectors normally which are very common for this type of fault. The diagnosis of this type of fault is very straight forward for a garage they just need to carry out a diesel leak of test this basically compares the injectors for the amount of fuel that is being returned to the tank . This fuel being returned is normal however when an injector is leaking internally it will return considerably more and this will be obvious when this test is carried out