I'd removed the right small cover first and an O-ring (with lump) just like the two where the white arrows are pointing showed up and I was cleaning the outer pan. Does it go around the center, larger attachment point? There is not a large O-ring on the rear (left) one.

Moving on the left side: After removing the fasteners, I tried to slip the cover forward since at that point I'd not detached the cables to the coils. From the very front, out popped the large O-ring I placed on the forward area (white arrow pointing to it), The middle one does seem to go back on just above. The one just forward (left) to it has a small O-ring and the one on the rear (right) is intact.

Is it at all possible that the O-ring that popped out when first removing the left cover actually goes on the rear (right) fastener opening?

In any event, where it was was just a hair from going down the timing chain opening.

Red arrow: I split the end when removing the end of the hose (I hate barbed ends). What is the correct name of the hose I should ask for?

I'd like to get this buttoned up today (4:30ish here) so if you have an answer or good guesstimate, please send it along.

Biba

 

Okay, I figured out that the O-rings are roll your own. It's just that MB's clever robots did it so neatly I assumed they were the real deal. However, I'm still curious how that one large 'O-ring' ended up in the oil filler section.

Also, I would appreciate knowing the name of the rear hose which attaches to the rear of the left side's small cover.

Nothing about the small covers, but I figured out that the lump in the front, upper center of the engine which looked like an electric turbocharger is an electric water-pump. Okay, I also recently discovered that there are two spark-plugs per cylinder. Do the connectors to the plugs pull off? They seem pretty determined to not let loose. Yes, I need to print out some of the available shop manuals.

 

Yea, all those "O rings" are really just the old RTV sealant.
The hose in question is the PCV hose, these M112 engines have no PCV valve, just that hose and a tiny hole inside the vent cap. ( make sure that hole is not clogged, but don't use anything that might enlarge it )

According to Rob at NeedsWings, that hose does NOT put any contaminants into the airstream before the throttle body, it more or less allows filtered air INTO the engine to equalize pressures.

I once took it upon myself to cap it off, as well as the connection to the single CAI I have. Bad idea.

 

Read the manual, that water pump is actually an air pump. It pumps air into the exhausts at start up to warm up the cats. It only runs for 30 seconds or so. It is a common cause for problems when the relay for it gets its contacts burnt etc.

 

I believe you are talking about the secondary air injection pump located on the drivers side towards the front of the engine bay. The water pump, is water only.

 

Naturally that's what I'm talking about, as that's what he is describing.
There is no water pump in that area.

 

Lol yea I know you know, I was just trying to clarify for the op.

 

I would pull both main covers off the car to thoroughly clean then before resealing them. doing it on the car is a shortcut that could go bad.

 

As a person that has done this a number of times, Rob (Needswings) is correct. To properly re-seal the breather (small) covers, one MUST carefully remove every last trace of old sealant.
And I mean Every last remnant. And both surfaces must be perfectly dry before application.

Doing it in-place is possible, of course. But I would spend the extra time.

P.S. the rubber valve cover (large) gaskets are re-usable if not damaged.

 

Thanks for the comments. I had no idea there was such an animal as air pump for the cats.

I don't understand the comments regarding not 'doing the cam covers in place vs off the car. Of course I removed the small covers (I'm saving the main cam covers for a rainy day) and thoroughly cleaned them of All of the old sealant as I also did with their mating surfaces. Among other cleaning items (I use lacquer thinner), a huge amount of Q-tips gave their lives for cleanliness.

I'd like to say that if there are no leaks tomorrow, everything should be good. Best I can tell is the problem was right above the hole in the lower panel - the A/C compressor. It is possible that oil came from above, but I doubt it. If I'm correct, no doubt it is the front seal.

I have no idea as to how this break and hole in the lower panel happened, but I didn't see any damage above it - either oil pan or compressor.

There are so many variables as to how long a front seal will last - but they're definitely the weak spot on A/C compressors.

Any advice?

Biba

 

I had a ton of errands to run earlier today, so planned it that about the last 15 minutes I'd be running the A/C compressor. Just now I checked and there was one half dollar size drip on the concrete right in the middle.

When running errands, there were a couple of times when I was turning the steering wheel sharply at low speeds, that I thought I heard what I'd assume was the steering pump. Is that normal?

I say this in that there is a veritable group of possible oil leakers on the left front of the engine: Small cam cover, main cam cover, upside down oil filter, steering pump, and A/C compressor. About the only thing missing is an actual oil rig pumping away.

One trick for cars with less items on the engine is to clean everything well, then shake baby powder all over the area where the leak might be coming from. Unfortunately this area on the XF is beyond seeable, let alone getting baby powder to stick upside down.

If I did install a new A/C compressor and came back from a run and later there was a big oil puddle under the XF, I'd be less than pleased.

Any one else go through this scenario? And if so, which one was the guilty party?

Biba

 

These cars are NOT nkown for oil leaks. From any source but the breather covers.
I was going to suggest what you did. Clean the living daylights out of it and drive/look/drive/look.

If it is the A/C-it should be very clear/obvious very quick.

 

An AC compressor typically only holds a few ounces of oil. If its dripping oil, it won't do it for long before its all out. If it continues dripping its an engine oil leak, not an AC leak.

 

MoparFreak69, I'm aware that there is little oil in the compressor, that is why I waited to turn on the A/C until I thought it could circulate enough to leak, or not. For now, it's working fine as far as cooling goes. I'll add that even in the Winter here cars get fairly warm inside after sitting in the sun.

maxcichon, I haven't pulled the filter unit off to see how my breather resealing handiwork is doing, but I will tomorrow.

However, I remain concerned that the oil around both the filter unit and steering pump might fall under what has happened to me way too many times for me to dismiss these as not being a problem. The far too many times is when the answer is, "Gosh, I've never seen this problem in this place before."

And while I can see that if the A/C compressor's seal is out, there are oily places (mostly cleaned up) around the oil filter unit and definitely the steering pump, that most likely would not get oil if it is solely the A/C compressor.

But, yes, I'll keep checking.

Biba

 

I've ruled out (for now) the steering pump. I did a hail mary and attached some paper toweling to a bent wire, dipped it in lacquer thinner, and ran it underneath the pump. It came back looking 'sooty' but no sign of fresh oil on it.

I'd cleaned the A/C pump before taking my roughly 12 mile trip yesterday. And as mentioned, only ran the A/C for about 10 minutes. I'd cleaned it prior to driving, and this is what it looked like. About a 12" puddle on the floor underneath it.

To repeat, since I can see oil between the pulley and pump, apparently the front seal did decide to let go.

However, check out the bolt head that the red arrow is pointing to. Is there any chance that the hole for it could go all the way through the block? Once I cleaned things off, it looked like there was black around the head - similar to the small cam covers silicone.

I could undo the bolt, but should it go through (doubtful), I need to be ready to change the oil/filter.

 

It would be good if I included the pitcher.

 

If it leaks much more you will need a pitcher.
I'd say you have an oil leak from the rocker cover myself, but what the heck do I know?
If you are going to run two threads on the same basic subject then members will just not bother to follow them, so keep it simple.
With all the leaks how much has the power steering level dropped? This should be the way to your answer.

 

onehundred80, by rocker cover, do you mean cam cover? I'll recheck it. but I did my best to clean both the cover itself and around the edges.

There are times when I don't check something first. Okay, there are a lot of times I don't check thoroughly first before making assumptions. In this case it was the steering pump, so felt it deserved its own thread - which it didn't.

Being on another major forum, I'm aware it is a no-no to post in two different places. However - and I've not done this ...yet - say I'm looking for info on a head unit. Logic says to go the the audio, electrical, etc. forum. but there are a lot more folks that are frequently on the XF Coupe forum. I have to admit, I find it hard not to post both places since the thread gets more eyeballs that way.

You, along with others, show up on most every forum I've been on. But I'm sure that a lot of members just go to the forum for their specific model. Then go to say the Engine forum, only when they have a specific engine problem.

Perhaps it is my lack of keying in the 'correct' term/terms on Search, but seldom has anything shown up that fits the info I need. An example of the one time it worked was the small cam cover thread. Whereas, I can't find a thing on the A/C compressor. I even visited a couple of Mercedes forums which catered to SLK320's and they also had nothing on A/C compressors - however, since I wasn't a member, perhaps it ignored my request.

I just want that danm oil leak to go away as quickly as possible.

 

The search function here (and other forums) leaves a LOT to be desired. It seems to take some time to know what terms to plug into it (with so many people mis-spelling words and using the WRONG terms to describe things).

But don't feel the need to post in several places - most of us look the forum over pretty completely when we come here. 100/80 more than most, too; not much escapes his attention.

You get extra points for knowing enough to search SLK320 on the MB forums! Don't be discouraged, the cars share enough in common that the MB forums CAN be of assistance.

 

I am sooo discombobulated. A little light went on, then got brighter, then it was just a matter of finding my quite nice combustable gas leak detector. With engine running and A/C turned on I snaked the long adjustable arm with red LED down past the A/C compressor's pulley, right up near to the shaft. This detector acts just like a geiger counter in that you let it run in clean air with a steady but slow clicking sound, once it detects a gas leak, the clicking increases, a lot if a bad leak.

The unit just kept clicking at the same speed. If oil is getting out, so should the 134. It was about 70 out when I did this and the interior was Very cold when I shut the motor off.

I really cleaned the compressor yesterday, except of course the area behind the pulley. There is a 2" oil spot directly under the center front of the compressor. Oy. I have the lower panel off so I could pinpoint where the leak was coming from.

Prior to this I revisited the left cam cover and short of a few dirty spots, there was no indication of leaking oil, nor was there any on the header cover. Yes, if hot, it would burn it off.

Very few of the cars I work on have A/C, but one that did, when I removed the entire A/C system, a ton of oil came out. Remember the compressor doesn't have its own oil reservoir, the oil goes in the same way the refrigerant does, then circulates through the system. But of course, the oil will eventually stop, as will the compressor if I keep running it. It varies but about 7 ounces of special compressor oil is pretty normal.

I don't think that I'll have anymore aha moments, anyone care to come up with one? Short of just replace the compressor on the basis of hey, it's only money and time.