Oil Pan Crack

[emerydc8]

I have been chasing an oil leak for well over a year and could never figure out where it was coming from. All I could tell was that after I parked for the night, oil would appear on the bottom of the oil pan, but nowhere else. Early-on, I changed the pan gasket using a very thin coat of sealant, but still the oil appeared. The perimeter above the pan always seemed to be bone-dry. The quantity of oil leaking has been slowly increasing.

Tonight, I had to change a Bosch voltage regulator that failed after less than 5000 miles (made in Taiwan). Before I started work, I sprayed the oil pan down with brake parts cleaner. It took about an hour to get the alternator out and back in. After I finished, the hairline crack in the pan was obvious--I could see the oil seeping through. I hadn't seen this in the past because I never examined the pan after spraying it down with brake parts cleaner and letting it sit for a period of time. I never would have thought the pan would crack like this. It almost looks like metal fatigue. While troubleshooting this leak over the last year+, I have been running with a rag stretched across the pan and kept from sagging with safety wire. The loss of oil between oil changes was insignificant. I hope the pan is still available. I see it listed at Annapolis for $111.60.

 

[nocfn]

Wow that is something. I too have just removed the Alternator since it is original and dead and whining. NO FUN but to find that is worse.

 

[kwontumspeed]

That's very odd indeed. I wonder if that's why they redesigned the pan. When you receive the new OE part you will notice that the bottom of the pan is different then original from factory. It is ridged.

 

[emerydc8]

I’ll take pics when it arrives.

 

[JC220]

I have never seen a cracked one that wasn't by result of mechanical damage. That is interesting and will be a pain to replace.

Presume this is a w124 chassis. To get the upper oil pan out you will need to disconnect the engine mounts and coolant hoses etc and raise the engine with an engine hoist or similar from above. Possibly need to disconnected exhaust etc too.

Is going to be an involved job I'm sure you know that anyway. Think of other items you could take care of, such as oil level sensor leaks and oil pickup donut etc.

And I'll quietly mention pull engine and trans could be "easier" in long run or at least mot many more hours and considerably less cursing.

 

[nocfn]

I dont think this is the upper pan it is the lower pan.

 

[emerydc8]

Thanks @JC220 The lower pan is all I need to remove. It was quite easy to remove and change the gasket. Nothing like my 1992 Z28 where you do have to unbolt motor mounts and lift the engine.

 

[kwontumspeed]

Yeah, upper would suck and also deepen the mystery of how that could happen. So glad it's the lower.
Easily found a pic, and you can see the indents on the bottom that was originally a flat area. Probably has nothing to do with the sides where your leak resides but I thought it was interesting it was different (and most likely due to the manufacturing process more than anything else).

 

[nocfn]

@emerydc8, since that lower pan was installed was there ever a situation where the pan was supported by wood to jack up engine or anything like that? If you hit something it would have had scratches so I agree it seems like fatigue and in the heat cycles it just broke. Wonder what the COO was. Must be Putin's fault.

 

[JC220]

Thanks @JC220 The lower pan is all I need to remove. It was quite easy to remove and change the gasket. Nothing like my 1992 Z28 where you do have to unbolt motor mounts and lift the engine.

Is the subject car an m119 V8 engine?

I seen your aluminium pan which is the upper oil pan material on an m119. Lower being pressed steel.

At first glance your photo looked like an aluminium surface to me, really bizarre if the mild steel pan has split!!

 

[gerryvz]

Something caused that. It almost looks like it was pushed outward from the inside. Changing the lower pan is easy.

I believe it is a common part number (the steel lower pan) that was used across multiple M119 engine types. For reference, the MB part number is 119 010 10 28.

EDIT: I agree with 281lxm ... that damage COULD have been cuased by strain on the pan from lifting it up from below to jack up the engine, causing fatigue and the bowing out of the metal in the side of the pan. That to me would be the most likely cause.

While you are in there, if you haven't already, you should proactively change the oil level sensor o-rings (there are a couple) as well as the rubber oil pump pickup. The o-rings are notorious leakers, and the pickup is a once-per-ownership change. Both are detailed in HOW-TO articles here.

If you have done those jobs already, then a straight pan replacement is in order. You should not need any sealant other than the gasket, but maybe a thin coat of hylomar wouldn't be a bad idea.

 

[gsxr]

FWIW... I've always had terrible success getting the lower pan to be leak-free after installing, even with an OE gasket, and carefully torqueing/retorqueing in a Kris Kross pattern. Frustrated with the (admittedly tiny) weeping, the last time I did the job, I applied a thin (!) coat of Right Stuff between the gasket and the lower steel pan, and left the upper part of the gasket dry. This resulted in a 100% dry pan for years afterwards, with Red Line synthetic in the sump. I plan to try the same method next time as well. If you try this, don't apply any sealant to the top side of the gasket! The sealant would be miserable to scrape off the upper aluminum pan sealing surface if the pan ever had to be removed again.

YMMV, etc etc.

Jon, that's depressing about the short lifespan of the Bosch-Taiwan VR's. 5kmi is inexcusable. The MB dealer is selling the same thing but at 8x the cost. You know something had to change when the Bosch-India VR was ~$50 and some of the new Bosch-Taiwan part numbers are <$15.

 

[nocfn]

I will be pulling the cover on both my reman alternators (only have one at the moment) to determine which COO the VR is on both.

 

[gsxr]

I will be pulling the cover on both my reman alternators (only have one at the moment) to determine which COO the VR is on both.

Reman alternators are far more likely to have either UK/GB or Indian VR's unless they are shiny fresh remans.

 

[gerryvz]

I will be pulling the cover on both my reman alternators (only have one at the moment) to determine which COO the VR is on both.

 

[nocfn]

I just got my reman out of storage and will check. I will also check the Partsgeek version I got yesterday. Still waiting on the FCP version that says MB ORIGINAL then it also says Bosch REMAN. When I get it I will edit my owner thread and here as well.

 

[emerydc8]

@emerydc8, since that lower pan was installed was there ever a situation where the pan was supported by wood to jack up engine or anything like that? If you hit something it would have had scratches so I agree it seems like fatigue and in the heat cycles it just broke. Wonder what the COO was. Must be Putin's fault.

I changed the motor mounts in 2013 and didn't have access to a shop crane at the time, so I used a piece of 2 x 4 and a jack. That could have caused it because the crack is approximately where the edge of the wood was positioned. It's puzzling that it took that many years to show up.

@gerryvz , I changed the oil sensor O-ring years ago so I will change it again while I'm in there. . Never did the rubber pick up so I'll add that to my parts order.

@gsxr , I remember @Klink saying that he puts a thin film of sealant on the gasket. I will do that again as the gasket never leaked and I have had problems in the past with pans leaking with just the gasket. The VR started the lights to flicker not only at lower RPM but at highway speeds, so I figured it's time to change it.

 

[emerydc8]

I was checking to see if AHAZ had a factory M119 oil pan gasket (119 014 08 22) to replace the gasket I'm going to use from my spares. When I searched their website with that part number, this kit came up: https://www.autohausaz.com/pn/1170100128KIT

It's listed as a Febi-Bilstein oil pan. Safe?

EDIT: Disregard. I see it's for an M117. It uses the same pan gasket but apparently a different pan. No wonder nothing came up when I typed in the M119 pan number (1190101028).

 

[emerydc8]

Yeah, upper would suck and also deepen the mystery of how that could happen. So glad it's the lower.
Easily found a pic, and you can see the indents on the bottom that was originally a flat area. Probably has nothing to do with the sides where your leak resides but I thought it was interesting it was different (and most likely due to the manufacturing process more than anything else).

Got the pan and other parts today. @kwontumspeed --You're right. The new pan is corrugated--probably in anticipation that someone is going to lift the engine with a 2 x 4 and a jack. Now if I could just get motivated to do the work.

 

[nocfn]

I used an 12'x12'x8" piece of red cedar to lift my engine. that corrugated pressed steal design was introduced to strengthen the pan, especially on the 126 which had notorious clearance issues hence the hardened steel belly pan cover - a far superior savior of the lower engine than the noise encapsulation panel Maybe the aluminum pan was contraband?

 

[emerydc8]

A few pics of the damaged oil pan. Who knows how it was dented and pushed in. What is interesting is that the hairline crack occurred at a point other than where the main swell was located in the pan and it ran perpendicular to it. As per @gsxr, @Klink and others, I used a thin film of gasket dressing only on the oil pan side of the gasket, ensuring that the other side was clean prior to installing. I criss-crossed the pan bolts and torqued them to 11 nm.

 

[TerryA]

@emerydc8, Interesting crack, I could see the crack coming from the pan possibly flexing but where did the dents come from?

How do you think the pan was damaged?

Do you know if your car ever ran over a
curb or a parking stop?

I could see the dents if you drove on a
gravel road with no engine tray installed.

I’m not pointing a finger just curious

lol

 

[emerydc8]

@emerydc8, Interesting crack, I could see the crack coming from the pan possibly flexing but where did the dents come from?

How do you think the pan was damaged?

When you have two drivers of a car, it's hard to tell. I have been behind vehicles on the interstate (usually semitrucks) that have kicked up objects that bounce and hit the bottom of my car. I'm not using the lower splash guard, so I could imagine a rock damaging the pan. In any case, I'm glad I found the leak and addressed it.