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Actually, that's part of the engine's pcv system, not a coolant hose. That hose routes blow-by air from the crankcase to the air intake just ahead of the turbo.
On my car this hose had perished and had a hole close to the turbo end. Any tear or damage to the hose can draw in unmetered air, potentially resulting in a poor air/fuel mix.
Mercedes only sell the hose as a complete unit (i.e. The entire tube running from the air filter to the turbo), but it's possible to replace just the damaged part with a short length of flexible hose. Otherwise, I think the complete hose assembly costs around $us 180 from memory.
Cheers, David
Thanks a lot! Definitely clarifies a lot! The car doesn't shift on a cold start from second to third gear till 3.2K RPM. Car is still under warranty (CPO) Hope they replace it for free. Is it normal that there is a slight amount of oil leaking out of it or does that indicate a leaking gasket?
The purpose of the PCV (positive crankcase ventilation) system is to remove pressurized, oily air from the crankcase and return it to the intake, which means any oil vapours are burned off rather than emitted to the atmosphere. Oil around a hole or tear in this hose simply confirms that it's leaking (oil vapour is normal in PCV hoses). By the way, the MB part number for the whole air tube assembly is 271-0890-20-29.
The purpose of the PCV (positive crankcase ventilation) system is to remove pressurized, oily air from the crankcase and return it to the intake, which means any oil vapours are burned off rather than emitted to the atmosphere. Oil around a hole or tear in this hose simply confirms that it's leaking (oil vapour is normal in PCV hoses). By the way, the MB part number for the whole air tube assembly is 271-0890-20-29.
Thanks a lot! Luckily enough I finally got my warranty enough, I got my warranty transferred and it'll be taken care of. Note that this is a 2012 vehicle. Any chance that you experienced any excessive carbon buildup due to the defect?
The damage to the hose won't make any difference to carbon build up in the intake (I assume that's what you're referring to?). It's likely that all of these direct injected cars will get some carbon build up on the intake valves over time.
Okay, so my CPO warranty apparently doesn't cover this part. I still am unable to find the part number for the clamp at the end of the hose. Somewhat disappointed so far with Mercedes of Boston, they failed to even notice the defect despite me pointing it out to them.
Had a car wash but they didn't even fill up the gas tank, despite putting 25 miles onto the car.
Strange that a defect like that isn't covered under warranty. Not a wear item I would have thought. Anyway, it is possible to replace just the damaged hose (the part circled in your first post) with a non original hose if you don't want to pay for the entire assembly. There isn't a clamp on either end of this hose, it's a push fit.
Great info her thanks for bringing this topic up bigab24!!
Follow up inquiry for Cbr944; what is the work around for the push fit if using non original hose? Can a hose clamp be used on either end? The hose connection on the top (see poster's pic) looks straight forward enough, but the connection at the turbo end looks more complicated.
Thank you and all of the respondents that respond to these forums. The money and grief that is saved by your actions is noticed and appreciated.
Mr.Biscuit
Yes it is straightforward to replace this hose with a non-original alternative and use hose clamps on both ends. To give yourself better access at the turbo end, all you need to do is unclip the hose going from the turbo to the intercooler (no need to remove the hose entirely, just unclip it at the turbo end).
Last weekend after doing my oil and filter change I was checking engine for cracked hoses/belts and miscellaneous leaks when I saw oil collecting at the turbo end of the hose. Inspected hose and the top connection was severed but resting in such a way that was undetectable unless you touched it.In my case the whole hose is shot but I don't think any shop would have caught it unless the problem was far enough along for oil to collect. Just saying.
So in order to repair this hose, one needs to replace the entire intake assembly. I don't have the exact part number but out of warranty it costs about $700 last time I recall.
Alternatively you can try to use this to fix the issue.
What kind of hose should i get to fix this issue and where can i get it. Really need to get it done asap!!
If you're looking to upgrade, the ModalWorks c250 cold air intake replaces that entire intake pipe with a larger diameter one. I highly recommend it. Better turbo spools, and throttle response.
Otherwise you can find the whole assembly online, I believe someone else posted the links above.
i fixed the coolant leak and replaced the eroded pipe connecting to the pcv system but i still have one more leak leaking from the bottom of the tube i’m pointing at. anyone know where i can get that tube and clamps from? really don’t want to pay to get it fixed at dealer or elsewhere to be honest
yeah i already bought the part and fixed it. worked very well. the pipe in the picture i posted is leaking though and idk what part to get to replace it. it has a pretty steady leak when the car is running so i’m losing lots of coolant
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