andreigbs

The MAF is likely fine, however the intercooler hose on the driver's side is likely leaking boost.
Read this thread from the top and you'll see what you need to replace and how.

vinglk

Thank-you for the reply . I did notice some soot on the passenger side hose . I will check the hoses when I get a chance .

Anchorman2020

Add me to the list of those replacing this driver's side charge air hose on my GLK250 at 47k miles. I ordered the replacement from MB Coral Gables, which had the best price I could find online. In the meantime, I cleaned the outside of the hose with brake cleaner & a blue shop towel (I know, not good for rubber long term), then used some high temp RTV gasket maker I had lying around to seal the 2 cracks (one was 1/2" the other was 1 1/2"), then wrapped duct tape around the whole area.

My question is this:
I noticed a small amount of oil in the hose (basically just coating the inside walls. Not enough to drip out when placed on end. Is this normal? I will check my oil level and make sure there it is not near the upper end of the fill line as mentioned elsewhere in this forum. But did anyone else notice oil, or were your hoses clean?

Also, given this issue, as well as all the emissions-related issues I've been experiencing on a vehicle with relatively low miles, I'm wondering if you guys did anything else to your GLKs, besides the usual routine maintenance.

Should I be cleaning the MAF sensor, EGR valve, etc? I don't want to create problems I don't yet have, but I also want to ward them off in advance!

Thanks in advance.

Flo109

Yes, there was a significant amount of oil in the cracked hose. I did not check yet the new hose, I only did a couple of thousand miles with it and everything seems to work very well. I'm skeptical about the temporary fix, I did the same thing and it didn't hold, as the hose dilates a lot. That made me understand why it burst so "soon" after only 50k. Speaking to some diesel mechanics from Europe, I found that actual is a pretty common issue, for all makes, since there's a lot of pressure in that rubber hose. However I find interesting how it burst exactly at 47k....

srb1194

Mine split at 72K. I also had some oily residue inside the hose.

Anchorman2020

Good to know, thanks for the replies Flo109 and srb1194. The new driver's side charge air hose came in today, will be swapping it in tomorrow. I discovered this issue only after bringing the car to the dealership for a CEL that my cheap obdii reader identified as P2002 (DPF particulate efficiency below threshold). I paid MB their $185 diagnostic fee and they told me about the cracked charge air hose, and that it would need to be replaced before they could rule out any other potential issues. I don't see how a cracked intercooler hose could be at all related to a P2002 code that's related to emissions treatment, but we'll see. They wanted to charge me $785 to replace the hose!

Did your CEL turn off after replacing the hose? Did you get the same P2002 code, or any others?

Planning on investing in a better OBD reader capable of clearing CELs and adblue/DEF related countdowns. I'm leaning towards the icarsoft MBii or V2 since they are fairly cheap at around $150, and it seems they can clear codes and even do the DPF regenerations. Is this correct? Anyone have experiences with these? I read that support is pretty weak with icarsoft. But the Autel that I was pointed towards is like $800 so I'd like to get by with a cheaper one that'll do the job, if possible.

srb1194

I actually never had a CEL. My daughter had reported a whooshing sound. Someone on this forum suggested I check the hose. I guess she didn’t drive it long enough to create a code. I have no knowledge on the readers.

bluecoupe05

I have an icarsot MB II with the latest software version available.and it can not clear permanent DTC's only pending ones. It also cannot do DPF regens on my vehicle.

Anchorman2020

srb1194, you are among the lucky ones then! Hope it stays that way for you.

Thanks for clarifying, bluecoupe05. I was kind of afraid of that. Shame it does neither. Will see what I can find on this forum about more capable OBDii readers.

bluecoupe05

You're welcome! The dpf regen option is available and I understand that a member on the forum did get it to work on their E250 however I was not able to get it to recognize my GLK 250

Anchorman2020

bluecoupe5, have you been able to get a dpf regen done by other means since then?

bluecoupe05

I haven't attempted to force a dpf regen by any other method. I may get a MB Star Diagnostic tool with Xenrty software, if I can find one used for a reasonable price.

Anchorman2020

Update: I brought the vehicle into the dealership after replacing the charge air hose myself because I was still getting the CEL throwing a code P2002. They wanted to charge me around $800 for a regen, I declined. I bought a few different additives, Diesel Extreme by Hotshots, Lucas Diesel Deep Clean, and Liqui Moly Diesel Purge. I opted to try the latter first, since it is made in Germany and is a really popular brand there. Took the GLK out for a "spirited" drive in sport mode; basically driving it like I was 17 again & looking out for police. Ran it for an hour solid, then a few hours later I drove hard heading home, with a cheap OBD reader plugged in. About 30 minutes into my drive back, I noticed there were no current codes and the CEL on my dash had turned off! I am now firmly in the camp of those who use quality additives in their diesel!

srb1194

Thanks for the update.

lovetheglk

Literally just registered today to the forum to resolve this exact set of codes, although they are intermittent. Sometimes it's both, sometimes it's P0101, and others it's P0299. I posted asking for diagrams showing where the MAF sensor is, to start by taking a look at that but can't seem to find photos/resources or a guide anywhere. I am not yet as car-savvy as I could be, but am learning. Any help starting this off would be hugely appreciated. I want to start by removing the MAF and reading some the airflow values. Advice for a complete noob?

Please don't say hire a mechanic. I have to wait until Tuesday, and wouldn't mind a small weekend project to learn more about this!

srb1194

Does this help?

lovetheglk

It does. I'm assuming #5 is the MAF sensor, which means I'd simply have to locate the air-box, and trace back from this diagram. I'm going to start by going underneath the car, and investigating for cracked hoses, as everyone else suggested in other threads with the same issues. Stepping out to grab chocks, and lifts now. Stay tuned!

EDIT: Yup, that's very evident on the diagram. Lol...

Tomcat9969

Funny thing (actually really sad), i could have written your post. My GLK 250 2014, same milage, same problem, Same error codes! The hose has a at least 2 inch tear. Just back in january, i had the same code. MAF. Replaced it, but light came back on right away. After investigating this, i saw a (almost exploded) red hose. this is the one on the passenger side. Got replaced, light came back on. Finally the decision was made to take the car to the dealership and it was on top of the hose...the airbox. So, two problems at the same time! Now, only 6 months later, it is the hose on the drivers side. I can just say, EVERY time the car needs to go for longer than just 1 hour, something brakes!
No i have one more question... both times the car was pulling something. First time a light pop up camper, the second time it was a trailer with a motorcycle on it...could that be an issue?? Any ideas??

lovetheglk

Update: I pussed out and took it to a mechanic to resolve but the research was sound. Told them what symptoms & codes it was experiencing, and that I bet it's the driver-side hose between the turbo (started failing to kick in, and down-regulated itself). Turns out the MAF code (P0101) occurs when you have an under-boost condition at a particular voltage for longer than 4 seconds OR as a redundancy code to P0299. They confirmed there was a crack. They also confirmed that the supplier cost for the driver side is 40% the cost of the passenger's side. Read somewhere that this was caused by the way the hose naturally sits within the engine bay once heat is applied.

They charged me $380 (CAD) all-in where Mercedes-Benz wanted north of $700 for the fix. The hose can be acquired from the likes of Rockauto for around $120. Services are known to be more expensive here in Calgary, AB area. I'm kind of annoyed I paid them for diagnostics, when it only took them an hour to fix the problem (if that). My confidence with repairs isn't quite there given my garage only, going under the car, access to an environment to work on it.

This thread was so valuable. Thank you!

andreigbs

Glad that you sorted the problem. It does seem quite common on these Bluetecs. I've checked both intercooler hoses from above and below at every oil change, including squeezing them with my hands to see if there are any cracks and so far after 122k miles, all is well. I've read that some people experience repeat tears/holes in that driver's side hose partly because of a metal part that may be rubbing on it. If possible, I would make sure there is nothing touching the hose. Good luck and happy dieseling.

srb1194

No i have one more question... both times the car was pulling something. First time a light pop up camper, the second time it was a trailer with a motorcycle on it...could that be an issue?? Any ideas??

Yes! Anytime you're under a load you're using more boost. As long as you're within the limits of the vehicle I wouldn't worry about it. If you're over the tow rating I'd make adjustments.

Thomas Krul

I've had this same issue - it happened while driving to Florida and part of the problem may just be load + heat. Until I could diagnose it as a cracked tube (typical on German cars, it seems, my BMW 3 series had cracks galore in its air tubing) I also noticed that it came and went with changes in temperature: e.g., when it's colder driving conditions, it seems to operate well (the plastic in the hose may be contracted enough to keep the fissure closed, slightly) while in hot temperatures (e.g., above 27C) the fault reoccured with greater frequency and side effects. In fact, it seems that the warmer it is while you have a crack, the more likely that the AC system will shut down as a protective measure. It's fairly idiotic.

slmskrs

I never got an error code (back around 55k miles). I was pulling a 3500# boat when I got a severe lack of power. Took it to the dealer; they identified it as the hose; they said it was a fairly easy fix, but didn't know anything about where it was, etc., at the time and my wife needed the car, so I had them do it (about $300). Now I know....

srb1194

It's one of the easiest and most successful repairs I've ever made.

dynamicax

Hi my GLK 250 started showing P0299 and P0101 , I erased the codes and now it's showing P0101 only. I examined the intercooler connection on the driver side and cannot find and crack yet. Maybe I need to take it off. Instead of replacing the pipe, I am thinking to clean the MAF and the air filter housing first.

I replaced the air filter myself about 7 months ago and should be still good.

I am wondering where the MAF is? In the picture attached, is that the round shape component connecting to the air filter?

There are two screws mounting to the air filter housing. If I take that off, do I have to put some form of sealant when I put it back on?