Originally Posted by pyatka

Hello everyone, we also just finish a swap. We put m273 RWD in 2010 c300 RWD. manual transmission.

Originally Posted by peanutpckrupper

Obviously it depends on the condition of your transmission, but I haven't had any issues with mine and I go wide open throttle every day.

Originally Posted by peanutpckrupper

Right.
V8, 6 speed GLK.

Originally Posted by ltwargssf

Unfortunately I ended up putting a 3.5L m272 from a GLK350 and its was bolt up and ran with the C300 ECU. I still switched the engine type in Xentry/DAS to 3.5L and its been great since.

As for the m273 swap, I've read through a lot of E550 and S550 owners having issue with the front yoke coming out of the transfer case snapping. The newer 4matic AMG's appear to have a similar 4matic design but don't appear to suffer from the same issue.



That splined shaft is very thin and I'm not sure how well it can hold up with the torque of a v8 if you drive the car hard a lot.

Originally Posted by Abass Diya

heyy ! i’m actually interested in this swap, i’m now doing a 6-speed manual from the c300 into my c350 , and need to know if the M273 can be swapped to the manual transmission! btw why don’t we just use the ECU of the M273 when we’re doing this swap ? or it has to be M272 ecu into the M273 engine ?

Originally Posted by Kompressor_5.5

Okay, question time.

First off, I just want to say coming from experience as an indie MB tech, you are guys over complicating it. Quit it. In hindsight, it is way easier than you think. Just relax.

Here are some acceleration videos: https://www.youtube.com/channel/UCpf...kTXlP-nxlzqhgg

UNLISTED VIDEO ON REVVING, WATER PIPE, SOLO ENGINE MOUNT TEST: https://youtu.be/1YaTQ142yBw

Motor mounts are a little broken? Huh, I wonder why?!

I don't have too many pictures or videos of the engine bay, some things got very interesting very quickly, and needed immediate modifications or relocations.
If the item/topic was not mentioned, it's probably stock/unchanged.
Keep in mind, I have full access to dealer level Xenry crap, as well as Abrites Mercedes stuff, ALL at my disposal. They are mine, saved my money, and bought them.
I have SEVERAL pictures of a friend's 2011 E550 4Matic, and if you were to cut off everything forward from the crash bar. It's identical. You can't tell the difference.

Here are the details for anyone wanting to do this yourself.

Body car: 2009 C300 4-Matic 155000 miles
Donor car: 2011 E550 4-Matic 60000 miles


The very first thing I did was fix what was already wrong with the car. The transfer case was leaking, oil change, thermostat, oh wait that's it. Then once that was done, I bought the motor from one of those pull-apart guys on eBay. $2k. Came with everything. Coils, plugs, intake, idlers, harness, but not A/C comp/Alternator/ECU.

Drop the motor in and saw what fit, and what didn't fit.

ALMOST everything lined up. Exhaust, harness, fuel line, axles, diff, oil pan, firewall were plug n' play. There were a few funky parts though.


NOTE: The distance FROM the firewall to the back of the heads is EXACTLY the same as the V6. With that being said, The oil pan and axles, bell housing, converter, heater core, and everything else on the back end, fit in absolutely no problem. The V8 moves the additional cylinders FOWARD in the engine bay. The excess room up front is taken up by the two extra cylinders.

SLIGHT Issues:

1. The power steering cooler, which was initially bolted to the upper oil pan, has been relocated to hiding underneath the oil pan, above the subframe, it's literally just resting there. Yes, it was put there for a reason, I live in a coldish climate, it's metal, and not touching any sharp things, not able to snag on-road debris, so I'm not too worried about it. Not too much I can do about it either because there is no room.

2. A/C low-pressure line bracket was unbolted from the body near the brake booster/front sam and the aluminum line was GENTLY molded to its new location. The engine moved forward. The original line was threaded in between the ABR and body perfectly centered. Now with the V8, the A/C comp is moved forward and I need the line that isn't there. Bend it! carefully!

3.The original upper hot side main coolant hose was pinched too tightly against the fan shroud, NOT the fan blades. This was how I drove the car for the first week or so. Left the coolant SLIGHTLY lower than where it so-post to be and left the coolant cap a little loose so I would build too much pressure. I might have blown this hose off twice before I narrowed down the reason why it was blowing off. Luckily I was joyriding it 1000 feet from my house and 1000 feet from the shop. No harm done. I had a welder friend weld me a custom water line. This line was Frankenstein from an M273 E55 A209 upper water tube and an M275 E60 W220 water tube. I cut the thermostat side from an M273 and the water outlet side from M275 and he welded them together. I should have used the M273 water outlet, M275 was too large. BUT WHY can't you just use the M273 A209 upper hose?! It was too small for the radiator fitting and the quick disconnect was 90 degrees off, so the clip won't even slide in. PLUS the engine sits too high to use that hose. The top of the aluminum water tube is PERFECTLY flush with the radiator fitting.

4. Vacuum lines. The original vacuum line on the W204 was gently heated to mold it to go on the intake manifold vacuum port, instead of the vacuum pump fitting. Drove on that for the first week or so. It's hard gooey plastic, wasn't worried about anything snapping. Already had the improved solution sitting on my toolbox. The solution was to buy 2011 E550 4matic brake booster vacuum lines, the ones behind the false firewall. The brake booster on w212 had n A212 part number. The brake booster on w204 has a A204 part number. DUH. BUT! The vacuum female fitting has the same exact location as the 2011 E550 4-Matic.

No specific info shown on this swap has been found anywhere, so sometimes you just gotta buy stuff and see if it fits. Bought vacuum lines, fed them behind the firewall, and drilled a hole in the firewall blank black plastic tab, boom.

5. ECU trouble. Went for a first start/crank, and it wouldn't crank, and had no CAN COM to VGS, no gated shifter status on the cluster. Ensured power was supplied to my 2007 CLS550 ECU. The problem was the CAN bus. 209/211/219 M.E9.7 doesn't have engine AND chassis CAN like 204/212/221 M.E. SO I grabbed used known bad w221 ECU for troubleshooting, drove it out on 4 cylinders. Solution? Buy 221 ECU. Virgined, personalized, activated. BOOM fired right up and drove it out a week later.

6. VGS. It took some learning for VGS to get used to my lead foot and torque/"boost" by gear. I did a trans service less than 500 miles ago due to a leaking transfer case sealant. It has a fault code saying that it's defective, and once in a while, it will refuse to start. DAS REFUSAL! Wait 5 minutes since the last key cycle and it's happy. The code could also be from getting torque/HP numbers it's not used to getting like it would be implausible to get 220 MAX HP then overnight get 400 HP.

7. Hot water valve. I really don't care about this one yet. I have left the A/C uncharged since the swap because I might change the low side hose out with something else. It's cold out so I'm ALWAYS using the heater. W221 ME has a code for the hot water valve. No CEL. The hot water valve on the engine I got doesn't have an electrical socket, the w212 harness doesn't have an electrical connector for it. So, it is what it is for now. My heat is hot. I'm happy. Might dig into variant coding later when It warms up outside.

8. Fan shroud gently rubs the P/S receiver. No vibrations transferred to the cabin.

9. Lower cold side rad hose "T" fitting would rub on the belt. I have broken motor mounts AND I somehow aligned the belt wrong. Solution? Motor mounts and Cable ties. Cable tied it to the trans cooler line for now. Not stressing the line out it's fine.

Why can't you use the M272 ECU on the V8? I don't know. Seriously. I was mad that I didn't drive it out on 8 so I tried everything. My Xenry won't allow you to change SCN Variant coding on W204's for some reason. Yes, I have developer mode on. You can on a w211 ME9.7 but not W204? Might just be something funky with my laptop. Changed Varient coding with Abrites though. Set it as an M273 W221. Still sounded like it only fired on like 2 cylinders while cranking. Wouldnt start. Can't see wire diagrams for an engine that never existed on a V6 ECU. So who cares.

Front SAM? Rear SAM? Central gateway? VGS? ABR? AAC? Nothing cares in the slightest about the V8. No one cares. Not a single unit. I still have no idea why.

Speed sensitive steering? I guess w221 ME97 doesn't care about it. It's not on the original pump, and the w212 harness doesn't have an electrical connector for it. No Events/Codes.

Original body/engine harness, A/C comp, Alternator, P/S pump+res.

If I wanted to I guess I could change all the Variant coding for every control module to set it as a v8 but what would I gain? Not a single event or fault code. Sooo why change it lol.

M.E and VGS are still adapting to the little monster this car is, so it's getting faster with time.
VGS gets upset when WOT at a standstill in comfort mode. Thuds back into 1st. Expected!
VGS also gets confused at WOT standard drive mode standstill. Just sits there and thinks before it authorizes the power to be delivered.

Stock fuel tune/fuel pump.

The front end is lower than it should be. I need to get some C63 springs. Rear-end slides out more than I want it to. Snow? No different from a 300.

Everything driveability on this car is like a 300. Absolute sleeper.

Some engine bay trim pieces are missing. Relax. Air snorkles whateverrrr..

Yes, I know it's dirty. There are a lot of things cosmetic wrong with this C-class. I don't care about cosmetic things.

I think it was wrecked in the front end.

I hope the power steering doesn't leak!

Customized ruined V6 E30 converter that conveniently stalls out at 3K. And recently shutters at 2k.

3.07 differentials. YES! I do spin the front tires! No, the ECU doesn't care for some reason. W221 S550 4-Matic USA has 2.65. W212 E550 4-Matic USA has 2.47.

I have absolutely no concern about power delivery from the engine to the wheels.
Differentials were probably used in w221 GUARD.
Axles were probably used in W221 or W212
Driveshafts are all W212 or W221
Transmission has a W204 case but W221 internals.

If they made a W221 550 4-Matic, N/A & TT, AND everything has a 221 part number on it, what makes you think it can't handle the power...? I'm not worried about it....

I love the 204's. People see me driving it and they could care less. But when I put my for to the floor, that's when people probably wonder wtf kind of c300 it is.


There is NO effing room between serp belt and fan. like none. Like if anything happens ill need to remove the water hose and fan, just to access the pullies.


NOTHING is rubbing where it shouldn't or doing anything it shouldn't. I could drive it cross country if the gas tank was bigger.


I got REALLY lucky with the car and all I have done to it.
11 MPG. Fuel tank lasts me 4 effing days.16 gallons worth. I love beating the crap out of this car.


NOW, I need to put in the wheel arch liner, New axle, flex disks, custom motor mounts, and some other crap.
I have an SLK230 as a slow back-up.


TOOK ME, AN 18-YEAR-OLD, ONE WEEKEND. If I can do it, so can you.
Just remember! Some guy from Colorado did the first 4-Matic conversion!!!

Originally Posted by smgak

If you simply swap the ECU over (and don’t tune it) then it should pass California emissions. Your biggest hurdle will be to convince the smog technician to ignore the extra two cylinders.