Had a small coolant leak going on the M271 2005 I had already replaced all known suspects. So I went straight to oil cooler replaced the oil cooler and gasket still had a tiny leak somewhere....

After further investigation it was that damn Coolant Pipe coming from the back of head. What was really strange not only was the o-ring severely worn the other half the plastic was burnt off...

I thought nothing off it replaced it drove it for a day and started smelling burnt plastic... was looking around saw that the back of cylinder head had this white soot everywhere and the same piece I just replaced had burnt off as well... How can this happen? Seriously confused I don't want to replace it again for the same thing to happen!

Photo of the original piece for visual aid.

 

Are you using an OEM pipe?

 

It was Rein but that wasn't the root problem.

The battery cable runs right underneath it and it some point the sheathing tore ( most likey a rat ) after I pulled the whole cable out I was able to see that it was damaged coming into contact with something metal cylinder head or the bracket causing this issue and other electronic issues as well.

 

Oh wow. Good thing it didn’t light up the rest of the car.

Just be glad our cars don’t use soy based wiring. The damage could’ve been much worse.

 

Very lucky could've been way worse! I'm hoping total damage is going to be under $400 new battery and other misc. parts etc...