hole appeared in inlet manifold

[pinkypanther]

hi everyone, i am new to this forum but can anyone help me get my head around how this inlet manifold on my 2016 sprinter has suddenly developed this hole? it can be seen clearly in the centre of the image that i have attached, the van was in the workshop to have a rear crank seal changed then on the way home it goes into limp mode then soon after a loud hissing noise coming from the manifold side of the engine, vehicle then recovered back to the workshop and a hole found in the manifold, so has anyone seen this perticular hole in a mercedes manifold before or what could have caused it to happen?
going to be an expensive repair and i am just confused how this can suddenly happened, any of your thoughts will be appreciated.

 

[pinkypanther]

i would also like to add that when i inspected the engine after it went into limp mode i noticed the vacuum pipe coming from the water pump was not connected, what problems could this have caused?

 

[Jobsworth]

Yes, seen it before. Hot gases from the EGR burn through. Worth checking the EGR valve is operating correctly

 

[markjay]

i would also like to add that when i inspected the engine after it went into limp mode i noticed the vacuum pipe coming from the water pump was not connected, what problems could this have caused?

My understanding is that the vacuum line controls the mechanical coolant pump, the idea is to reduce coolant circulation while the engine is cold on order to speed up warming (similar to what the thermostat does).

 

[Mickyh7]

If its not a new vehicle, I'd be tempted to fill the whole area with bodywork filler. If it comes off easily, even better, fill fromm both sides.
It doesn't do anything other than hold a vacuum!

 

[Gazwould]

Despite an egr cooler egr gasses are still hot enough to melt a hole in plastic which should of been metal .

 

[Jobsworth]

If its not a new vehicle, I'd be tempted to fill the whole area with bodywork filler. If it comes off easily, even better, fill fromm both sides.
It doesn't do anything other than hold a vacuum!

And turbo boost pressure…

 

[Railwayman]

I know I'm going to sound like an old fart (I am) but cannot stand all this plastic crap they use in car engines nowadays, I realise weight is an issue but metal would be my choice.

 

[Mickyh7]

And turbo boost pressure…

Do you have any idea how strong modern filler is?
What's the boost pressure?
About the same as Mrs Miggens farts!

 

[E55BOF]

I know I'm going to sound like an old fart (I am) but cannot stand all this plastic crap they use in car engines nowadays, I realise weight is an issue but metal would be my choice.

It's not weight, it's cost-cutting, surely? Plastic is cheaper and much easier to cast than metal.

 

[Tonygw]

Its both cost cutting and weight, and a bit long term business model in the mix to.

Cost cutting, as injection moulding, plastics forming is much faster and cheaper than casting metal components.

Its weight saving as all manufacturers strive to reduce weight to make their vehicles 0.0002% more efficient than the competition, & comply with EU regulations etc... (EU regulations are one of the biggest drivers of lightweight cheaper materials use in cars these days in the name of efficiency .. (Thanks for that)

And the plastics (as most components these days ) have a 10 year design life, meaning by 10 years they could fail... prompting the general public to trade in their old car for a shiny new one. good for new car sales, growth.. etc..


Fun times.

I would say this manifold failed before its design life so another factor, like "egr" gases as mentioned is probably a contributor to the failure, and not the fatigue failure of the material itself.

 

[Mickyh7]

Its both cost cutting and weight, and a bit long term business model in the mix to.

Cost cutting, as injection moulding, plastics forming is much faster and cheaper than casting metal components.

Its weight saving as all manufacturers strive to reduce weight to make their vehicles 0.0002% more efficient than the competition, & comply with EU regulations etc... (EU regulations are one of the biggest drivers of lightweight cheaper materials use in cars these days in the name of efficiency .. (Thanks for that)

And the plastics (as most components these days ) have a 10 year design life, meaning by 10 years they could fail... prompting the general public to trade in their old car for a shiny new one. good for new car sales, growth.. etc..


Fun times.

I would say this manifold failed before its design life so another factor, like "egr" gases as mentioned is probably a contributor to the failure, and not the fatigue failure of the material itself.

Expansion and contraction on a daily basis over years is a major factor in fatigue of materials. Both metal, and plastic. A piece of dirt or nylon in the blow moulding process would also weaken the skin.
Nylon contamination is a big problem when moulding next to a fuel tank operation, as the small pellets are used in fuel tank manufacture, along with plastic pellets.