gloe plugs

[cadmans]

hi ive got a merc c250 td its getting hard to start in the morning the glow light is ok but it takrs about 4/5 times to start will i need new glow plugs and were are they on the engine left or right hand side ive changed the before on a ford . ive had this car 9 mth its got high milage but runs ok when started thanks

 

[Tinkerer]

They should be on the near side of the engine and the control unit is also on that side on the top of the wing. You probably already know if you have done them on a ford before but check for continuity first to find the ones that are open circuit.

 

[SilverSaloon]

They should be on the near side of the engine and the control unit is also on that side on the top of the wing. You probably already know if you have done them on a ford before but check for continuity first to find the ones that are open circuit.

i'm surprised the glow plug light works correctly if any of them are dead.

does the light come on and then off when you turn the key to pos 2 (not starting engine).... and never comes back on when the engine is running?

you can easily check which glowplugs are dead by testing them at the relay end with a multimeter....

check out this link for a "how to":

Mercedes Diesel Glow Plug Repair

 

[Dieselman]

It's more likely to be an air leak causing poor starting.