Glow plugs OM 651.921

[kirkan777]

Hello, hope everyone well. Can somebody help me with my enquiry please, I'm looking to buy glow plugs but there is two types and they are in two different lengths 148.9mm and 158.9mm. Which one do i need? Maybe there is any technical data.
2014 C Class C250

Thank you.

 

[W1ghty]

Hello, hope everyone well. Can somebody help me with my enquiry please, I'm looking to buy glow plugs but there is two types and they are in two different lengths 148.9mm and 158.9mm. Which one do i need? Maybe there is any technical data.
2014 C Class C250

Thank you.

Buy both ,return the unused set ?

 

[kirkan777]

Buy both ,return the unused set ?

Yes, probably it is the best option. Thanks