Hi!

Looks like I have an oil leak...I don't really see it in the front of the engine. But I do see it on the lower side in the back of the engine. The top of the engine doesn't leak but I see oil residue in the picture below.
What do you think is the cause of the leak and how can it be fixed? Car only has 25,000 miles so surprised there is an oil leak already. I guess to fix this engine would need to be lifted out of the engine block. Seem like it's a lower valve cover leak?

Thanks for any help with this!

 

Oil level sensor maybe ??

 

Could you elaborate just a little? Does the oil level sensor lead to oil leaks? Thanks for your reply.

 

Don't panic. It is highly unlikely the engine would need to be removed to do a high percentage of the most common repairs. Your leak appears to be minimal and could be coming from the valve cover gasket. This is a common problem but I would wait a while and keep monitoring it. Most oil leaks are related to leaky seals or gaskets. Remember, even though your car only has 25k miles it is 16 years old. Some gasket materials degrade when immersed in oil over time. Once you find where the leak is coming from I would recommend you have a local MB repair shop verify the leak and have them fix it if you are not mechanically inclined. Do not go to a Chrysler dealer as most on this forum will tell you. They know nothing about our German cars.
Cheers

 

have you checked the transmission electrical connector on passenger side of trans ? Connector o rings fail and cause leak in that area

 

Your pictures are TOO close up for my taste, but I looks like breather/valve cover leaking to me. So common, it's no longer considered a surprise OR a big deal.
You will be fixing this twice, the first time, you will do the repair without really paying attention to the experiences of those of us who TRY to tell you how to do it.

THEN, in six months, when it starts leaking again, you will take your time and do it right.
(I, of course, read Maxchion's warning, like the one I just wrote to you, and did it right the first time. I probalby had six hours in the fix, but here we are, six years later, and my engine is a clean as the day I did the fix).

IF it IS the valve/breather covers, start reading:
https://www.crossfireforum.org/forum...over-leak.html

 

If you can indentify that the breather covers are leaking , re-torque your valve cover bolts to 7 ftlbs , then remove and re-seal both breather covers with a good RTV sealant it's also the age of the sealant and not just the mileage that leads to failure. Here's a video on our M112 engine also shared with Mercedes

 

We had better your statement a little clearer.
You use 7 ft lbs on the large cover bolts and 4 ft lbs (48 in lbs) on the (2) or (3) 6 mm aluminum screws. If the aluminum screws have been replaced by steel screws as the aluminum screws are only used once, I would still use 4 ft lbs, remember it is the material and size of the thread that the screws are screwed into that figures into the equation as well.
Using the aluminum screws more than once is risking breaking a screw in the cover.

 

The valve cover bolt torque is 7 ftlbs , the torque for the aluminum screws on the breather covers is covered in the video

 

True, but I think that all the info should be in one place as it is in many threads on the forum.

 

When I put my engine back together, that was, at age 56, the FIRST time I used a torque wrench.

You see, it's the only time I was concerned about over tightening a bolt. I don't do that much mechanical work, and I knew there was a great possibility I'd screw this one up.

So many years later, still no leaks. When I take my time and really try, I'm actually pretty good at this wrenchin' stuff.

Photo from last summer.

 

Yeah, when I inherited my father's '04 XF with 50K on the clock that had been sitting for 2 years with a dead battery and a wasp nest in passenger wheel well (got stung replacing the battery), I started it up and a few minutes later it started to smoke as oil was burning off the exhaust manifold. Leaking valve cover. However, I didn't worry about it. I saw the oil residue there and figured the seal had dried up and separated a bit somewhere and car just needed driven again for a while. So, fast forward 1-1/2 years and just getting hot oil flowing around the inside of that valve cover and that cover's sealant combined with overall engine heat the leak sealed right back up on its own immediately... No more leak, no more smoke, no more problem. I personally don't worry about any oil leaks unless it gets to the point that oil needs top be added between oil changes and even then I'm not overly concerned. Old cars can burn oil and leak oil. Oil is cheap, the European auto repair shop is expensive if you're not a DIY'er willing to get into that level of repair.

I'd take an XF that has been driven relatively regularly with 100K on the clock over a dry-rotted garage queen with 10K on the clock all day long... Probably couldn't drive the garage queen home without leaving 1/2 the vital fluids on the road along the way.

 

Thanks very much for everyone's input. It's definitely the lower valve cover. Top valve cover is perfectly fine and no leaks..
Been reading up on the job and DEFINITELY don't want to do it wrong/twice 🤣.
Now the question is should I fix it or wait till it gets worse. Post above makes it sound like as long as oil doesn't need to get topped off between oil changes it's probably fine.
I don't want to tackle this now but would rather push it off for another 6 months or so if not immediately necessary.
Gives me more time to really make myself familiar with this job and dedicate enough time to do it right the first time. Plus I'll have access to a garage at that point and don't have to do it in the parking lot in the Florida heat.

 

Try the simplest first, re- tightening the valve cover bolts, they loosen over time: torque is 7 ftlbs If you do replace the valve cover gaskets it would be the perfect time to replace your spark plugs if needed, makes it a lot easier

 

Going to do that first this weekend. But need to buy a torque wrench that is capable of low torque numbers. Mine starts at 14.5 lbs ft. I'll see if that helps before tackling the valve cover resealing.

 

Get yourself a quarter inch drive torque wrench in inch pounds. 1 foot pound is 12 inch pounds.
Handy torque wrench especially if you are working on motorcycles, wouldn't be without one.
Don't risk over torquing, you'll be sorry.
Good luck.

 

If the actual gasket is leaking between the valve cover and block, I'd bet tightening things up will do it.

Just WATCH IT, the smaller bolts in the breathers screw into the valve cover, leave them alone. Just tighten the larger bolts that go thru to the block.

 

Drive the car more. From the pics you posted I see no signs of any oil leak that requires immediate service. If there were a leak that caused reason for concern you'd spot oil on the ground under the car where it was parked, you'd smell or see smoke from oil burning on the exhaust manifold. Next time you park the car since it is in a parking lot that generally has stains all over the pavement from various cars being parked in various spaces put a big piece of clean cardboard under the area from a box and see if you find any drips on it the next day or over several days. No significant drips seen on the cardboard = no major problem in my opinion. I think you're worrying about nothing (but I could be wrong of course).

 

WRONG. If he shows up at a meet and we see a dirty engine, he will be shamed, cursed, laughed at and talked about when he leaves.

He's gotta fix this and clean the engine off fast, before anyone sees it.

 

LOL! Well, remind me NEVER to bring my XF to any meet! My inherited XF has somehow become my wife's daily driver (not sure how that happened but it did). It's a cool car and I'm happy she gets to drive something fun and unique every day that turns heads. These aren't vintage garage queen Porches or Ferraris or something... They are vintage Mercedes SLK's with a cool Chrysler wrap and that's all they are.