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My 2008 C300 needs an engine. I'm looking at scraps for a used replacement one and thinking of getting a 3.5L upgrade. Every mechanic locally is hesitant on the swap working but people on forum seem to have done it and the C300 ECU will run the 3.5 without problems? I need to be sure they fit so I'm not stuck with a 3.5L that doesn't run properly..
Anyone? The scrapyard has an engine from a 2012 GLK350 with 67 000km and they only want 1200$CAD. I need to know if the stock ECU from my 2008 C300 3L will run the 3.5L before I make that investment.
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
I am interested as well, but don’t like your chances it will work out well with out a lot of faffing around.
You have to remember even if it mates up and starts the C300 ecu injects enough fuel for a 3L engine not a 3.5L engine.
Next thing you have to ask yourself who do I have to carry out the engine swap and would they know how to correct the above problem.
I am interested as well, but don’t like your chances it will work out well with out a lot of faffing around.
You have to remember even if it mates up and starts the C300 ecu injects enough fuel for a 3L engine not a 3.5L engine.
Next thing you have to ask yourself who do I have to carry out the engine swap and would they know how to correct the above problem.
Looking at this, there appears to be a selection for the type of engine with Xentry. My car does not support DAS with the scanner I have so I would need to do this in Vediamo instead.
Yea, you'd need vediamo, and this should be an easy swap.
What happened to your engine?
I talked to a local shop that guarantied me it will work since he's swapped 3.5s in c230s and c300s before. Apparently i will just need to go in with my Xentry and do an engine reset/adaptation once the engine is in. Theres no going back now, I checked out the engine today before they pulled it out of the car and it basically brand new. 2012 glk350 that got rear-ended with only 62 000km so I couldn't pass that up. It will be a nice upgrade over my 292 000km 3L.
Let's just say I wasn't nice too it and it was one red line too much. Its unfortunate since it didn't burn any oil and it ran so good for having just about 300k on it. I haven't confirmed exactly what went wrong but cylinder 4 has zero compression, my guess is the timing chain skipped a tooth at redline. If you are going to be pushing these engines, I recommend a minimum of a timing chain tensioner replacement at 250k and have the chain inspected.
I talked to a local shop that guarantied me it will work since he's swapped 3.5s in c230s and c300s before. Apparently i will just need to go in with my Xentry and do an engine reset/adaptation once the engine is in. Theres no going back now, I checked out the engine today before they pulled it out of the car and it basically brand new. 2012 glk350 that got rear-ended with only 62 000km so I couldn't pass that up. It will be a nice upgrade over my 292 000km 3L.
Subscribed and interested to see this develop and your final feedback and review of the 3.5 compared to the 3.0 you are used to. Best of luck and take pics for us.
I managed to make it work before our city was put on lockdown. Anyone with a C230/C250/C300 equipped with the m272 can fit a 3.5L from anything like a GLK350 / E350 / S350, etc..
Everything was bolt up except a bracket for the differential was slightly different(4matic only) for the GLK350 so I had to reuse mine from the C300. The dipstick is also a little different so make sure you get one with the donor 3.5L. Otherwise, a very easy swap that bolts up and no need for ECU tuning. Just make sure to have a Xentry scanner at hand to reset the engine and transmission adaptions and you are good to go.
You definitely feel a little more torque and top-end power over the 3L m272.
I managed to make it work before our city was put on lockdown. Anyone with a C230/C250/C300 equipped with the m272 can fit a 3.5L from anything like a GLK350 / E350 / S350, etc..
Everything was bolt up except a bracket for the differential was slightly different(4matic only) for the GLK350 so I had to reuse mine from the C300. The dipstick is also a little different so make sure you get one with the donor 3.5L. Otherwise, a very easy swap that bolts up and no need for ECU tuning. Just make sure to have a Xentry scanner at hand to reset the engine and transmission adaptions and you are good to go.
You definitely feel a little more torque and top-end power over the 3L m272.
Oh wow! Congratulations. I didn't expect it to be this simple and I'm surprised you didn't have to change the engine model in Xentry. You only had to reset the adaptations and that's it?
As you drive the car more, let us know how gas mileage is affected in relation to the bump in horsepower and torque.
[QUOTE=xsever;8015717]Oh wow! Congratulations. I didn't expect it to be this simple and I'm surprised you didn't have to change the engine model in Xentry. You only had to reset the adaptations and that's it?
As you drive the car more, let us know how gas mileage is affected in relation to the bump in horsepower and torque.
The only thing I did was a torque converter adaptation, transmission adaption, and engine adaption Just the typical resets after a big job on a Mercedes. I am sure it would've learned by itself, the resets just make it faster I assume.
Gas is so cheap right now, its hard to tell but honestly, the difference in MPG is negligible so far. According to my research, on paper, a 2008 C300 4matic gets 17/25mpg whereas a 2008 C350 RWD gets the same 17/25mpg. My guess is about 1mpg was lost with the 4matic system.
As far as power goes, I've had the 3L for a long time and can definitely tell the 3.5L has a throatier sound to it as soon as I started it. It definitely has more torque and top-end power, I wouldn't say a drastic difference but its noticeable. Il be looking for a tune to get the most out of the 3.5L.
Oh wow! Congratulations. I didn't expect it to be this simple and I'm surprised you didn't have to change the engine model in Xentry. You only had to reset the adaptations and that's it?
As you drive the car more, let us know how gas mileage is affected in relation to the bump in horsepower and torque.
The only thing I did was a torque converter adaptation, transmission adaption, and engine adaption Just the typical resets after a big job on a Mercedes. I am sure it would've learned by itself, the resets just make it faster I assume.
Gas is so cheap right now, its hard to tell but honestly, the difference in MPG is negligible so far. According to my research, on paper, a 2008 C300 4matic gets 17/25mpg whereas a 2008 C350 RWD gets the same 17/25mpg. My guess is about 1mpg was lost with the 4matic system.
As far as power goes, I've had the 3L for a long time and can definitely tell the 3.5L has a throatier sound to it as soon as I started it. It definitely has more torque and top-end power, I wouldn't say a drastic difference but its noticeable. Il be looking for a tune to get the most out of the 3.5L.
Congrats on the successful engine swap. I’m glad I wasn’t aware of this mod back in the day when I had a sup’d up W204 C300 Sport. I would’ve totally tried to pull it off. Please enjoy
Oh wow! Congratulations. I didn't expect it to be this simple and I'm surprised you didn't have to change the engine model in Xentry. You only had to reset the adaptations and that's it?
As you drive the car more, let us know how gas mileage is affected in relation to the bump in horsepower and torque.
The only thing I did was a torque converter adaptation, transmission adaption, and engine adaption Just the typical resets after a big job on a Mercedes. I am sure it would've learned by itself, the resets just make it faster I assume.
Gas is so cheap right now, its hard to tell but honestly, the difference in MPG is negligible so far. According to my research, on paper, a 2008 C300 4matic gets 17/25mpg whereas a 2008 C350 RWD gets the same 17/25mpg. My guess is about 1mpg was lost with the 4matic system.
As far as power goes, I've had the 3L for a long time and can definitely tell the 3.5L has a throatier sound to it as soon as I started it. It definitely has more torque and top-end power, I wouldn't say a drastic difference but its noticeable. Il be looking for a tune to get the most out of the 3.5L.
I have a 2008 C300 4m and brother has 2010 GLK350...yes the 350 definitely is throatier...I know exactly what you mean...smoother as well.
It is cool that you successfully did this swap. Also, parts for the 204s are relatively inexpensive because there are so many of them out there.
The real question is whether you can swap a 2013+ M276 3.5 V6 into a 2008 C300. Obviously that gets a little more complicated with the programming and fitment cause it's a newer gen motor in an older gen car with older transmission. I'm sure some experts on here with the right equipment could do it.
My C300 is in nice enough shape, but worth so little as a pre-owned car that it may just be worth it to swap a bigger engine into it just as an upgrade. Maybe $5K installed? https://www.ebay.com/itm/2013-2014-M...dc84d151cecc32
Keep in mind with a tune the M276 makes 302 hp.
Last edited by LandSeaAir; Mar 27, 2020 at 04:48 PM.
I have a 2008 C300 4m and brother has 2010 GLK350...yes the 350 definitely is throatier...I know exactly what you mean...smoother as well.
It is cool that you successfully did this swap. Also, parts for the 204s are relatively inexpensive because there are so many of them out there.
The real question is whether you can swap a 2013+ M276 3.5 V6 into a 2008 C300. Obviously that gets a little more complicated with the programming and fitment cause it's a newer gen motor in an older gen car with older transmission. I'm sure some experts on here with the right equipment could do it.
My C300 is in nice enough shape, but worth so little as a pre-owned car that it may just be worth it to swap a bigger engine into it just as an upgrade. Maybe $5K installed? https://www.ebay.com/itm/2013-2014-M...dc84d151cecc32
Keep in mind with a tune the M276 makes 302 hp.
Unfortunately, swapping an m276 would be much more involving. The fuel pumps are different because of the direct injection, thats the first thing that comes to mind. You would definately need to program the ecu for the swap unlike just going 3L to 3.5L. Getting the ecu with the m276 then hack it to vin code it to your car, if thats possible. Regardless, the swap would be too involving, you would be better off just buying a 2012+ c350 or 2013+ c300.
The next swap would be with the m273. Next time I see one, I will look if the wiring harness is the same because everything else is bolt up to our cars if you have a m272. If the m272 ECU can run the m273 v8, that would be a very easy swap as well.
Unfortunately, swapping an m276 would be much more involving. The fuel pumps are different because of the direct injection, thats the first thing that comes to mind. You would definately need to program the ecu for the swap unlike just going 3L to 3.5L. Getting the ecu with the m276 then hack it to vin code it to your car, if thats possible. Regardless, the swap would be too involving, you would be better off just buying a 2012+ c350 or 2013+ c300.
The next swap would be with the m273. Next time I see one, I will look if the wiring harness is the same because everything else is bolt up to our cars if you have a m272. If the m272 ECU can run the m273 v8, that would be a very easy swap as well.
So from my research on m276 to m278 swap from the same generation C300 and E550, the wiring harnesses are different because you do have two additional cylinders in the m278; however, the pin socket is the same. I talked to some xentry specialists over the past 2 months (because i really really want to stuff that 4.6L Biturbo in my C300) and he said it will be a matter of re-programming the current ECU as Mercedes in the same generation share the same ECUs.
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
Well done, 10 out of 10 for successful completion of your engine swap.
Great news finding all the software was already there just needed selecting on to change engine capacity.
My 2010 c300 is nearing 200k miles and was actually considering this swap. Where are you located? Curious which shop got it done for you.
Any shop can do it really, I'm just good friends with a mechanic and I didn't have a lift otherwise I would have done it myself. It's very easy to remove/install engines on these cars, about 1000-1500$ in labor at most. It's a plugin play install, you won't need any reprogramming. Almost every shop will be hesitant about mixing engines on a Mercedes but I've done almost 25 000km since the swap and its been great.
Any shop can do it really, I'm just good friends with a mechanic and I didn't have a lift otherwise I would have done it myself. It's very easy to remove/install engines on these cars, about 1000-1500$ in labor at most. It's a plugin play install, you won't need any reprogramming. Almost every shop will be hesitant about mixing engines on a Mercedes but I've done almost 25 000km since the swap and its been great.
Thanks for the advice. I will definitely visit this later down the road. My alternative would be to find a used c350 but it's getting hard to find a fully equipped one. And a c63 is just not suitable for a daily for me. There's the w205, but I'm really not a fan of the w205 with the exception of the interior.
Would love to hear more about your update on how the car has been since the swap. I think the 300 and 350 motors have different compression ratios and have just been wondering if that would require ECU coding for proper fuel economy. Have your MPGs been normal?
Reason I am asking is cause I recently just learned that Mercedes made a tuned version of the M272 350 motor for the SLK350 that makes 300hp. It's basically the same as the C350 motor with minor changes. If possible, it'd be awesome to swap into my high mile C300.
From 2009 SLK brochure...somehow just learning about the existence of this engine now. Oh and most notably, it revs to 7200rpms instead of 6250. So clearly the 300 ECU would need to be modified. Still working on figuring out if changing the RPM limiter via developer mode is possible.
Last edited by LandSeaAir; Nov 11, 2020 at 11:22 PM.
Would love to hear more about your update on how the car has been since the swap. I think the 300 and 350 motors have different compression ratios and have just been wondering if that would require ECU coding for proper fuel economy. Have your MPGs been normal?
Reason I am asking is cause I recently just learned that Mercedes made a tuned version of the M272 350 motor for the SLK350 that makes 300hp. It's basically the same as the C350 motor with minor changes. If possible, it'd be awesome to swap into my high mile C300.
From 2009 SLK brochure...somehow just learning about the existence of this engine now. Oh and most notably, it revs to 7200rpms instead of 6250. So clearly the 300 ECU would need to be modified. Still working on figuring out if changing the RPM limiter via developer mode is possible.
Funny, I was just looking at SLK350 intake manifolds for a little more power. I have since put an X-pipe on my car and removed the torque limiter via Xentry (DAS). Car is running great and smooth as ever and with manual mode programmed and the paddles working, its a blast to drive. I was always weary for an aftermarket tune to get more power but I also drive a lot so reliability and mpg is important to me. The slk350 intake manifold would be a nice upgrade but I am not sure how well and reliably it would work without a proper tune. If the SLK350 only had the different intake, you could jsut go in with Xentry and change the engine tune setting to the SLK350 but it seems our m272's have 10.7:1 vs the slk's 11.7:1. The intake must be good for about 15-20hp tops, im sure the compression difference makes up for most of it.
As for the intake manifold, I am curious what exact part number the throttle body to know if its specific to the SLK350. I was looking at m273 v8 thorttole bodies and they appear to be larger.
Funny, I was just looking at SLK350 intake manifolds for a little more power. I have since put an X-pipe on my car and removed the torque limiter via Xentry (DAS). Car is running great and smooth as ever and with manual mode programmed and the paddles working, its a blast to drive. I was always weary for an aftermarket tune to get more power but I also drive a lot so reliability and mpg is important to me. The slk350 intake manifold would be a nice upgrade but I am not sure how well and reliably it would work without a proper tune. If the SLK350 only had the different intake, you could jsut go in with Xentry and change the engine tune setting to the SLK350 but it seems our m272's have 10.7:1 vs the slk's 11.7:1. The intake must be good for about 15-20hp tops, im sure the compression difference makes up for most of it.
As for the intake manifold, I am curious what exact part number the throttle body to know if its specific to the SLK350. I was looking at m273 v8 thorttole bodies and they appear to be larger.
Did you install the paddles? Was it just plug and play + xentry enabling or did you have to add wiring?
That'd be cool swapping the SLK intake manifold in. If/when I get an SLK350 motor I will let you know the throttle body numbers. And yes, I'm not sure about the parameters of Xentry tuning and programming a 300 ECU to work with SLK350. But look above--the regular C300 motor has a different compression than the C350 motor (11.3:1 vs 10.7:1). I'm guessing by now you changed your 300 ECU to C350? But above you noted your 350 motor ran fine with a 300 ECU so who knows maybe compression isn't an issue.
Benzninja who responded in above thread i think is saying he could adjust the individual ECU parameters as opposed to just selecting the model type in xentry.
Did you install the paddles? Was it just plug and play + xentry enabling or did you have to add wiring?
That'd be cool swapping the SLK intake manifold in. If/when I get an SLK350 motor I will let you know the throttle body numbers. And yes, I'm not sure about the parameters of Xentry tuning and programming a 300 ECU to work with SLK350. But look above--the regular C300 motor has a different compression than the C350 motor (11.3:1 vs 10.7:1). I'm guessing by now you changed your 300 ECU to C350? But above you noted your 350 motor ran fine with a 300 ECU so who knows maybe compression isn't an issue.
Indeed you are correct, i wasn't aware about the 3L having a higher compression compared to the 3.5. It did run fine with the stock 3L ECU with no error codes but I did change the engine setting in Xentry, there is an option that allows you to put whatever engine you want, it didn't change the way it drove.
As for the paddles, every w204 has the wiring and connectors from factory, for some, they just plug it in and it works and others like myself, requires coding. The problem is the factory paddles will act like your tiptronic and show as D1-D2-D3 ... I was lucky enough to find someone that was able to program the transmission and give me Manual mode, probably the best thing I ever did to my car since I always drive it in manual mode now. The shift speeds are night and day compared to the tiptronic/normal paddle setting. I just had to sacrifice my Comfort option so now when I press the C/S button on my shifter, I only have Manual mode or Sport.
Last edited by W204Motorsports; Nov 12, 2020 at 11:32 AM.
Indeed you are correct, i wasn't aware about the 3L having a higher compression compared to the 3.5. It did run fine with the stock 3L ECU with no error codes but I did change the engine setting in Xentry, there is an option that allows you to put whatever engine you want, it didn't change the way it drove.
As for the paddles, every w204 has the wiring and connectors from factory, for some, they just plug it in and it works and others like myself, requires coding. The problem is the factory paddles will act like your tiptronic and show as D1-D2-D3 ... I was lucky enough to find someone that was able to program the transmission and give me Manual mode, probably the best thing I ever did to my car since I always drive it in manual mode now. The shift speeds are night and day compared to the tiptronic/normal paddle setting. I just had to sacrifice my Comfort option so now when I press the C/S button on my shifter, I only have Manual mode or Sport.
I'm looking into this now--manual mode with or without paddles. Apparently there's a fourth mode called "Agility" or A. They sell OBDII plug and plays apparently. It seems like you may be able to have all four modes activated at once but we'll see. I think A is the speed of the manual shifts but D1-D2 etc.
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