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Good afternoon y’all, this is a question for those that did the m273 engine swap on the w204, so we ran into a little problem about the oil pan, since my friend that I bought the project from got the s550 engine, I was told to get the e class oil pan and I’ll be fine, well the e class oil pan has 4 bolts but the s class has 3, now it probably won’t fit. I know of somebody that also used the s class engine but lost contact with him so I am hoping there is still somebody out there that knows the exact correct oil pan I can use. Your help will be very appreciated.
The first picture is the 2010 e class oil pan and the second picture is the s class oil pan, still on the s class engine (not sitting right because the sump is in the front)
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
I just completed a w204 engine swap with an s550 engine. I ended up using an e550 pan and don't remember having any issues with the bolt patterns. If you look at the upper pan on your engine, there are actually more bolt holes that should line up. I can get under the car this weekend and get a picture for you if you need one.
It's possible that MB changed the bolt pattern between years. I used a 2007 s550 engine, and unfortunately I'm not sure what year e550 pan I got. It was not in the eBay listing.
Last edited by Quadprism; Feb 13, 2025 at 11:45 AM.
I just completed a w204 engine swap with an s550 engine. I ended up using an e550 pan and don't remember having any issues with the bolt patterns. If you look at the upper pan on your engine, there are actually more bolt holes that should line up. I can get under the car this weekend and get a picture for you if you need one.
It's possible that MB changed the bolt pattern between years. I used a 2007 s550 engine, and unfortunately I'm not sure what year e550 pan I got. It was not in the eBay listing.
oh wow, I did a lot of research and thought none of the pans will still fit, I turned to getting a custom oil pan made, please send pictures as soon as you can, thank you. This really gives me hope, finding someone that used the same engineto, I thought I was cooked.
If im understanding correct those two pans you show will mount to the engine. The bottom photo shows the bottom pan, but above that inside the pan are the 4 bolt holes to mount to the engine. The bottom photo showing "3 bolts" are the bolts going to the upper pan.
Im not familiar with the M273 but I have the M272 and I know there are two different pans depending on if its 4matic vs RWD.
Heres the top view of the pan in the 1st photo: Forward on right side
Heres the top view of the pan you show on the bottom. Forward on the left side.
If im understanding correct those two pans you show will mount to the engine. The bottom photo shows the bottom pan, but above that inside the pan are the 4 bolt holes to mount to the engine. The bottom photo showing "3 bolts" are the bolts going to the upper pan.
Im not familiar with the M273 but I have the M272 and I know there are two different pans depending on if its 4matic vs RWD.
Heres the top view of the pan in the 1st photo: Forward on right side
Heres the top view of the pan you show on the bottom. Forward on the left side.
So basically what I’m getting is that the sump bolted to the front is what makes it seem like it has 3 bolts instead of 4 and if the sump is removed, I will find where the 4 bolts fits? Thanks so much, makes a lot of sense, I will keep yall updated.
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Originally Posted by Mike4l
oh wow, I did a lot of research and thought none of the pans will still fit, I turned to getting a custom oil pan made, please send pictures as soon as you can, thank you. This really gives me hope, finding someone that used the same engineto, I thought I was cooked.
I got the C550 up in the air today and got a picture of the front of the pan for you. It's kinda hard to see in there with the full radiator stack in place, but you can see the 4 bolts on it. C550 Front of oil pan
I got the C550 up in the air today and got a picture of the front of the pan for you. It's kinda hard to see in there with the full radiator stack in place, but you can see the 4 bolts on it. C550 Front of oil pan
you are correct, currently in the process of taking it off.
I went on eBay and searched for "Mercedes M273 oil pan". Then scrolled through for all the different oil pans that are shown.
This pan has part# 2730142202
This pan has part# 2730142302:
thanks so much, this made me confident that I should be fine, I was about to start looking into getting a custom pan made, thanks so much, I will keep yall updated.
I got the C550 up in the air today and got a picture of the front of the pan for you. It's kinda hard to see in there with the full radiator stack in place, but you can see the 4 bolts on it. C550 Front of oil pan
also congrats on the completion, any new mods coming? Exhaust or anything? Are you looking into gaining more power?
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Originally Posted by Mike4l
you are correct, currently in the process of taking it off.
You'll also need an e550 or cls550 oil pump. I think that the pickup tube will bolt to the s550 pump, but I just bought a whole pump assembly to be safe.
You'll also need an e550 or cls550 oil pump. I think that the pickup tube will bolt to the s550 pump, but I just bought a whole pump assembly to be safe.
yea I figured, is it the black plastic type of pick up tube? Just trying to know if I got the right one.
You'll also need an e550 or cls550 oil pump. I think that the pickup tube will bolt to the s550 pump, but I just bought a whole pump assembly to be safe.
Did yours look like this? Or you had the metal tube?
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Originally Posted by Mike4l
yea I figured, is it the black plastic type of pick up tube? Just trying to know if I got the right one.
You'll need the long one. The pump stays at the front of the engine, but the sump moves to the back when you swap the e550 pan on. Cls550 oil pickup tube
You'll need the long one. The pump stays at the front of the engine, but the sump moves to the back when you swap the e550 pan on. Cls550 oil pickup tube
thanks, just got the pickup tube a couple days ago, the oil pan fits perfectly, new problem is the motor mounts, the offset is not right so the bolts are not allied, what did you do? Did you get custom mounts? Or what part number did you get? Thanks. Can’t really get a good picture but yea it doesn’t sit right.
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Originally Posted by Mike4l
thanks, just got the pickup tube a couple days ago, the oil pan fits perfectly, new problem is the motor mounts, the offset is not right so the bolts are not allied, what did you do? Did you get custom mounts? Or what part number did you get? Thanks. Can’t really get a good picture but yea it doesn’t sit right.
You'll need the V6 motor mount brackets and C350 motor mounts. The brackets directly replace the V8 brackets minus the rear AC compressor brace. I just cut that part off the V8 brackets using a hacksaw. You'll see what I'm talking about when you look at the brackets.
Don't do what I did initially and use an abrasive based cutting disk or tool on the aluminum brackets or you'll ruin it. The aluminum is soft and just fills the gaps in the abrasive instead of sparking/burning off the way steel does.
Last edited by Quadprism; Mar 11, 2025 at 03:08 AM.
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Originally Posted by Mike4l
also congrats on the completion, any new mods coming? Exhaust or anything? Are you looking into gaining more power?
I guess I just missed this last time I checked the forum.
The V8 is the only power mod I plan to do. If I wanted more performance, I would've found a C63. I'm really just building it to be a fun but comfortable daily driver with good performance and good reliability. I picked up the C350 base for cheap since it's engine had skipped time, and I already had the M273 on hand, so I figured I'd stuff it in and call it a day. Besides the engine and a trans tune to make it run right, it'll be stock. The only hint it's not a regular C350 is the 5 I stuck on the back to make the badge read C550.
I may put an exhaust cutout on at some point to let out the awesome sound! The m273 is probably the best sounding engine I've driven besides the M156.
You'll need the V6 motor mount brackets and C350 motor mounts. The brackets directly replace the V8 brackets minus the rear AC compressor brace. I just cut that part off the V8 brackets using a hacksaw. You'll see what I'm talking about when you look at the brackets.
Don't do what I did initially and use an abrasive based cutting disk or tool on the aluminum brackets or you'll ruin it. The aluminum is soft and just fills the gaps in the abrasive instead of sparking/burning off the way steel does.
Sorry, can you explain the ac compressor brace part a little better? Are you saying I have to cut it? Thank you.
I guess I just missed this last time I checked the forum.
The V8 is the only power mod I plan to do. If I wanted more performance, I would've found a C63. I'm really just building it to be a fun but comfortable daily driver with good performance and good reliability. I picked up the C350 base for cheap since it's engine had skipped time, and I already had the M273 on hand, so I figured I'd stuff it in and call it a day. Besides the engine and a trans tune to make it run right, it'll be stock. The only hint it's not a regular C350 is the 5 I stuck on the back to make the badge read C550.
I may put an exhaust cutout on at some point to let out the awesome sound! The m273 is probably the best sounding engine I've driven besides the M156.
yea I’ve been trying to find people who did the same swap with exhaust modification, I plan on changing the exhaust pipe to 3in diameter for better exhaust flow and more power also put a tune on it from oe tuning even though it doesn’t gain much hp.
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Originally Posted by Mike4l
Sorry, can you explain the ac compressor brace part a little better? Are you saying I have to cut it? Thank you.
You need the V6 brackets to offset the motor mounts to fit the subframe. The left and right brackets bolt directly onto the V8, but because the V8 is longer, the V6 AC bolt hole is too far back. You'll need to add something to mount the rear of the compressor and the easiest way is to just cut the section off of the V8 bracket.
Last edited by Quadprism; Mar 11, 2025 at 12:05 PM.
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Is this a C300 or C350? Those are directly compatible with the M273 with some minor bolt on modifications. I'm pretty sure the C250 has a different subframe and you'll need to swap it for a C300 or C350 RWD subframe.
Is this a C300 or C350? Those are directly compatible with the M273 with some minor bolt on modifications. I'm pretty sure the C250 has a different subframe and you'll need to swap it for a C300 or C350 RWD subframe.
Is this a C300 or C350? Those are directly compatible with the M273 with some minor bolt on modifications. I'm pretty sure the C250 has a different subframe and you'll need to swap it for a C300 or C350 RWD subframe.
can you recall any other modifications after you got past the motor mounts?
2009 C550 M273 5.5 swap, 2006 Chrysler Crossfire SE (M137 swap in progress...)
Originally Posted by Mike4l
can you recall any other modifications after you got past the motor mounts?
I used the engine accessories from the V6. It was easier to attach and route the alternator/starter wiring from the C350. I kept the M273 starter and attached it to the C350 power harness. The alternator could probably be used from the S550, but the power steering pump and AC compressor and lines need to be from the C350.
You'll also need to reroute the cable for the oil level sensor. The S550 wiring harness has it in the front, but the E550 pan has it in the back. It's a single wire, so I just spliced a new wire to add another connector at the rear level sensor location. If you add a wire, you can check that it'll work by checking the continuity between the old connector and the one you add with a multimeter. Other than that, I didn't have to modify my wiring, but your milage may vary.
I used exhaust manifolds from a CLS/E550 since they amazingly have the same geometry as the C350 manifolds. They bolted straight to the stock C350 exhaust.
Another issue you'll have is the cooling hose at the thermostat. The C350 hose will not fit without rubbing on the fan. I solved the problem with a CLK550 thermostat housing which has a pipe that runs behind the oil filter and has a regular hose barb on the end. It's very tight up against the PS reservoir, so I may modify it in the future so that the barb comes out at a different angle. I think the CLK550 has a remote PS fluid reservoir that would solve the issue, but I'm not totally sure if that's the case.
I used the engine accessories from the V6. It was easier to attach and route the alternator/starter wiring from the C350. I kept the M273 starter and attached it to the C350 power harness. The alternator could probably be used from the S550, but the power steering pump and AC compressor and lines need to be from the C350.
You'll also need to reroute the cable for the oil level sensor. The S550 wiring harness has it in the front, but the E550 pan has it in the back. It's a single wire, so I just spliced a new wire to add another connector at the rear level sensor location. If you add a wire, you can check that it'll work by checking the continuity between the old connector and the one you add with a multimeter. Other than that, I didn't have to modify my wiring, but your milage may vary.
I used exhaust manifolds from a CLS/E550 since they amazingly have the same geometry as the C350 manifolds. They bolted straight to the stock C350 exhaust.
Another issue you'll have is the cooling hose at the thermostat. The C350 hose will not fit without rubbing on the fan. I solved the problem with a CLK550 thermostat housing which has a pipe that runs behind the oil filter and has a regular hose barb on the end. It's very tight up against the PS reservoir, so I may modify it in the future so that the barb comes out at a different angle. I think the CLK550 has a remote PS fluid reservoir that would solve the issue, but I'm not totally sure if that's the case.
don’t the cls and clk 550 use the same thermostat?
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