Strong oil burning smell but no visible leaks
#1
Strong oil burning smell but no visible leaks
2014 C250 (W204)Luxury. 1.8t.
Was serviced about a month ago and no leaks noted then. About two weeks ago it has started to give a strong oil burning smell but I am not finding any leaks. I need to get under the hood and find it. I am thinking it has to be around the turbo. Figure it’s burning off anything before it drips further.
Searching around the web I have seen a Bango fitting with a smaller opening. From previous turbo cars I have worked on I don’t understand why you would ever want to reduce oil for your turbo, but at the same time there has to be a reason why someone came up with a custom banjo fitting like that.
Has anyone have thoughts on the smell for one and the custom banjo for the other.
Thanks
Calvin
Was serviced about a month ago and no leaks noted then. About two weeks ago it has started to give a strong oil burning smell but I am not finding any leaks. I need to get under the hood and find it. I am thinking it has to be around the turbo. Figure it’s burning off anything before it drips further.
Searching around the web I have seen a Bango fitting with a smaller opening. From previous turbo cars I have worked on I don’t understand why you would ever want to reduce oil for your turbo, but at the same time there has to be a reason why someone came up with a custom banjo fitting like that.
Has anyone have thoughts on the smell for one and the custom banjo for the other.
Thanks
Calvin
#2
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Join Date: May 2014
Location: MELBOURNE VICTORIA AUSTRALIA
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w2010 w204 c300 amg sports package
check oyur cam plugs and pcv oil seperator and the brake vacuum pump they are situated near the firewall ....
so ud have to feel with your hand to see if there is a leak, normally it drips onto the exhaust and creates that burning smell
hence why there are no leaks , cuz the exhaust burns it up and thats why u get that burning smell
i had the SAME issue and replaced the brake vacuum pump and all good now...but remember to check the cam plugs and the pcv oil seperator
so ud have to feel with your hand to see if there is a leak, normally it drips onto the exhaust and creates that burning smell
hence why there are no leaks , cuz the exhaust burns it up and thats why u get that burning smell
i had the SAME issue and replaced the brake vacuum pump and all good now...but remember to check the cam plugs and the pcv oil seperator
Last edited by huotalicusC200K; 01-29-2019 at 02:20 PM. Reason: more info
#5
Senior Member
After about 5k miles of oil change I also smell oil in the garage when the car has been driven but I don't smell that after an oil change. So, I think in my case it's the older oil smell that way when it's hot.
#6
Found the issue
So after cleaning, looking, cleaning, looking... Still didn't find anything. Then I had to take the car for a long drive for work, when I finally got to my destination and again I started to smell it after a while of driving. Something caught my eye and when I put my hand on the tube it flexed and that's when I figured it out.
Look at the photo and there is a tube that runs from the Turbo and it appears to run up into the air cleaner. I have not gone thru all the parts of how this turbo system works and what each item does or tubes, but what I "THINK" is that this is part of the Turbo bypass system, as such it releases excess pressure from the turbo and puts it back into the air intake. AGAIN, NOT SURE! If someone can explain it, I would love to know. Either way, I found the issue. That tube and where it connects, the flex tubing of it was cracked. Stopped by a AutoZone and bought come F4 tape (that's what the military calls it) and a couple of zip ties. Its been that way for a couple of weeks now and no more smell, so I am pretty sure that was the issue. I figure it was blowing out into the engine compartment and then coming in from the fresh air vents, being sucked into the cabin.
Now if I could only get JUST that part number I could research it and buy one. Really have no desire to take it to the dealership for it.
What I am afraid of is that this is a cause from another issue that needs to be fixed. I might have a check valve that is NOT opening up and thus, the hose is getting to much pressure. AGAIN... NOT SURE!
The following 2 users liked this post by Calvin4038:
Hakan117 (04-21-2021),
idrnkthekoolaid (11-26-2019)
#7
W204 cgi engine air suction pipe renewed
I had same problem. Changed the hose set. The part w204 cgi engine air suction hose is sold as a complete set. Majority problems comes from one thin hose leaks oil/air. At first I tried to use leak bands, but didnt worked. This part is not as usual soft rubber hoses, its something like hard rigid plastic HDPE and oil resistant.
Last edited by Hakan117; 04-21-2021 at 07:01 AM.
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#9
#10
The little hose you broke and fixed with tape and a zip-tie is part of item #40 in Hakan117's parts diagram list. Mercedes does not sell the 2 hoses separately, only as a single, expensive unit that includes the big hose and small hose together. It is several hundred dollars.
BUTTTTTT... you can buy the small hose by itself for about $6 on Amazon. You may need to use an exactoknife or razor utility knife to slice the softer plastic hose fitting ends to get them off (be careful not to puncture anything else) and then "definitely" use a small film of motor oil over the push-on fitting so that the new hose slides on the fittings as it is hard to push them on.
The part number/Amazon item is:
I saw this hose was cracked at the fitting when I was changing the crazy stupid PLASTIC coolant lines that run from the back to the front of the motor. Those are also expensive at almost $200 at Mercedes but got them for $30 with 2-day shipping on Amazon. Lots of youtube videos on the failing plastic coolant lines. Mercedes vehicles work great, when they work.
BUTTTTTT... you can buy the small hose by itself for about $6 on Amazon. You may need to use an exactoknife or razor utility knife to slice the softer plastic hose fitting ends to get them off (be careful not to puncture anything else) and then "definitely" use a small film of motor oil over the push-on fitting so that the new hose slides on the fittings as it is hard to push them on.
The part number/Amazon item is:
Car Air Intake Pipe Mini Hose Rubber Intake Turb Charge Pipe for Benz W172 W204 W212 2710901929 A2710901629
Car Air Intake Pipe Mini Hose Rubber Intake Turb Charge Pipe for Benz W172 W204 W212 2710901929 A2710901629
I saw this hose was cracked at the fitting when I was changing the crazy stupid PLASTIC coolant lines that run from the back to the front of the motor. Those are also expensive at almost $200 at Mercedes but got them for $30 with 2-day shipping on Amazon. Lots of youtube videos on the failing plastic coolant lines. Mercedes vehicles work great, when they work.