Oil smells like fuel
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 38
Likes: 0
C43
Oil smells like fuel
Hey guys,
I'm in the middle of re-sealing my lower oil pan and noticed that my oil smells like fuel. Generally I associate this with something like a stuck injector but the car runs fine as far as I can tell. No CEL's. Very few miles on this oil so that doesn't bode well.
I just finished doing plugs/wires, gaskets, etc etc.
Is there anything Mercedes/C43 specific that I should be testing/looking for? Anyone else experience this?
I'm in the middle of re-sealing my lower oil pan and noticed that my oil smells like fuel. Generally I associate this with something like a stuck injector but the car runs fine as far as I can tell. No CEL's. Very few miles on this oil so that doesn't bode well.
I just finished doing plugs/wires, gaskets, etc etc.
Is there anything Mercedes/C43 specific that I should be testing/looking for? Anyone else experience this?
MBWorld Fanatic!
Joined: Jan 2007
Posts: 1,152
Likes: 29
From: Sydney, Australia
190D 2.5 (x2), 190E 2.6, W202 C240,W202 C43 (C55), W210 E55, W212 E250CDI
One thing comes to mind, did you replace the rocker cover gaskets? When you did them did you remove the fuel line from the rail? If you did then it leaks fuel into the cylinder head whilst the rocker cover is off.
Other than that there is nothing common at all for this one. Shorter trips can add a little more fuel to the oil, I would change the oil and recheck after a few weeks.
Other than that there is nothing common at all for this one. Shorter trips can add a little more fuel to the oil, I would change the oil and recheck after a few weeks.
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 38
Likes: 0
C43
I did have that all apart but I put the oil in afterwards. I'm pretty sure I drained the dribbles out before I put the new in as well, though there may have been some residual. It smelled pretty strong for such a short mileage on the oil.
I'm leaning towards FPR or injecors. Injector testing is about 20-25$/per. I haven't been able to find a FPR yet, I don't suppose anyone has a PN on that? It almost looks like you have to get the whole rail?
I'm leaning towards FPR or injecors. Injector testing is about 20-25$/per. I haven't been able to find a FPR yet, I don't suppose anyone has a PN on that? It almost looks like you have to get the whole rail?
MBWorld Fanatic!
Joined: Jan 2007
Posts: 1,152
Likes: 29
From: Sydney, Australia
190D 2.5 (x2), 190E 2.6, W202 C240,W202 C43 (C55), W210 E55, W212 E250CDI
The fuel pressure reg is part of the fuel filter, It's not in the rail.
If the injectors were that bad you'd smell it in the exhaust on cold start pretty easily. I'd say it's just spillage from when you changed the rocker cover gaskets.
If the injectors were that bad you'd smell it in the exhaust on cold start pretty easily. I'd say it's just spillage from when you changed the rocker cover gaskets.
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 38
Likes: 0
C43
Boy I hope so. I really don't want to put fresh oil in and have it contaminated immediately. When I get it started I'll check at the back for any fuel odor. I'm right about 135k miles and I'm guessing by the state of the rest of the car that the fuel filter is original. I will probably go ahead and do that soon. I feel like if any sensors were out far enough to be dumping that much fuel in that it would throw a CEL (on a German car at any rate)
Thanks for the heads up on the FPR/fuel filter, I was wondering why I couldn't find it!
Thanks for the heads up on the FPR/fuel filter, I was wondering why I couldn't find it!
MBWorld Fanatic!
Joined: Apr 2006
Posts: 1,101
Likes: 40
From: Bay Area, CA
98 C43, 15 Alfa 4C LE, 18 Tesla Model 3 DM Perf, 08 Duc S1000, 02 Duc 998, 98 Duc 748, 01 Miata
Run some cheaper oil in there if you're just planning to run it and flush it. No need to spend $60 on throw away Mobil 1. Once the situation is solved, then put the Mobil 1 back in.
There aren't very many situations where fuel and oil would interact. You can try the injector cleaning service. I had the injectors on my bike cleaned by RC Engineering and they did before and after flow charts which was kind of cool. Turned out one injector was good and the other benefited from the cleaning.
There aren't very many situations where fuel and oil would interact. You can try the injector cleaning service. I had the injectors on my bike cleaned by RC Engineering and they did before and after flow charts which was kind of cool. Turned out one injector was good and the other benefited from the cleaning.
Trending Topics
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 38
Likes: 0
C43
I didn't smell any fuel at cold start up at the tailpipe after I put the oil in. Idles fairly smooth and drives smooth. When I get the injectors out I may go ahead and pull the plugs to see if anything is obviously too rich. I did run a tank of Techron through but the gas was about 8 months old so I'm not sure how much good it did- in terms of potentially sticking injectors.
What I'm seeing is witch hunter, and RC for injector cleaning services. Witch hunter is slightly cheaper I think.
What I'm seeing is witch hunter, and RC for injector cleaning services. Witch hunter is slightly cheaper I think.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Junior Member
Joined: Oct 2012
Posts: 38
Likes: 0
C43
I got the new fuel filter/fuel pressure regulator in. The clamps on the old one looked original at 130k miles so hopefully that is eliminated as a potential issue. Next is injectors. It's kind of hard to tell if you've fixed it without going through a million quarts of oil, haha!
