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I have a e63s amg m157, no tune but do have down pipes, all o2 sensors plugged out for the car to run richer. My car is currently blowing blue smoke, yes I know it’s burning oil, I have checked the intakes no oil, I have checked both sides for the PCV valves, plugged them out and still continuing to blow smoke, I have done a compression test all pistons are running at 160 psi. I had taken out spark plugs, I will attach a photo of the order I’m going in, piston 1,4,7 & 8 have oil residue on them, clear indicator that’s it’s burning oil, if it was the rear of the turbos leaking there wouldn’t be any oil residue on the spark plugs, no oil leaks visible, I was thinking it was the valve stem seals but no smoke when you first start the car only when starting to rev the car. I am stuck in this situation and don’t know where to go from there.
ps: make sure to unplug the oil pump actuator sensor, Mercedes done a stupid job in putting one to lower oil pump pressure at low RPM to save fuel. Just a nice little heads up ruins the engine. Photo off the web 1 2 3 4 5 6 7 8 Photo off. Wen
Last edited by creative khal; Dec 30, 2025 at 08:37 AM.
I would boroscope the cylinders. Wet pistons can make compression appear higher than it really is. These engines have an issue where if the last person didn’t do short oil change intervals and let the car properly warm up, it likely has stuck rings or dirty rings and needs to be cleaned up. I personally used all the different types of chemicals safely with the caveat that I know exactly what I’m doing and how to use safe procedures. Also, despite many people’s feelings in the younger days of this engine, the valves do deserve a cleaning before they drop their carbon chunks into our delicate cylinder walls.
Last time I watched a video of a compression test on an M157. The cylinders were all 190-200 psi.
I had done some research, typically the compression would usually be between 130psi and 170psi, 170 indicates good of course, also if compression isn’t good then they all wouldn’t be showing the same readings due to the fact cylinder 1,4,7 & 8 has oil residue on the spark plugs, that given I wouldn’t think rings are the problem…. Or am I wrong
Last edited by creative khal; Dec 30, 2025 at 11:17 PM.
I would boroscope the cylinders. Wet pistons can make compression appear higher than it really is. These engines have an issue where if the last person didn’t do short oil change intervals and let the car properly warm up, it likely has stuck rings or dirty rings and needs to be cleaned up. I personally used all the different types of chemicals safely with the caveat that I know exactly what I’m doing and how to use safe procedures. Also, despite many people’s feelings in the younger days of this engine, the valves do deserve a cleaning before they drop their carbon chunks into our delicate cylinder walls.
i will be going to try get a camera today to check them out, I’m from Australia Melbourne, I’m very familiar with performance work and people in the industry ( garage Worx, RPM performance group, very known ) I’ve been told 160 is very good and I shouldnt worry about piston rings. I can try cleaning everything but what kind of product would you recommend and where exactly should I be cleaning?
Last edited by creative khal; Dec 30, 2025 at 11:12 PM.
i will be going to try get a camera today to check them out, I’m from Australia Melbourne, I’m very familiar with performance work and people in the industry ( garage Worx, RPM performance group, very known ) I’ve been told 160 is very good and I shouldnt worry about piston rings. I can try cleaning everything but what kind of product would you recommend and where exactly should I be cleaning?
I’d say wait until you scope to think about cleaning. Then, you can do a piston soak, with whatever chems people use locally. If not a sludge engine, also something like Liquimoly engine flush. For the upper end, you need physical cleaning of the valves, then gdi cleaners after for maintenance. Also, using a pea additive in the fuel can help clean the rings. Most people might say to do short oil change intervals with a premium brand oil that has good cleaning capacity, but for me, I wouldn’t want to drive around for potentially the next 10,000 miles hoping things would clean up.
I say that the compression might actually be unknown now because those wet cylinders might lower if they were dry. The scope will show you the full picture there…
I’d say wait until you scope to think about cleaning. Then, you can do a piston soak, with whatever chems people use locally. If not a sludge engine, also something like Liquimoly engine flush. For the upper end, you need physical cleaning of the valves, then gdi cleaners after for maintenance. Also, using a pea additive in the fuel can help clean the rings. Most people might say to do short oil change intervals with a premium brand oil that has good cleaning capacity, but for me, I wouldn’t want to drive around for potentially the next 10,000 miles hoping things would clean up.
I say that the compression might actually be unknown now because those wet cylinders might lower if they were dry. The scope will show you the full picture there…
I use 10-40 hi tec liquimoly oil with the oil ceramic wear and protection additive, I put close to 9 litres of oil and 2 bottles of the additive, that’s my first service ever since I’ve bought the car. I have some more ready to go for next service I’ll try doing an engine flush & try clean the bores out after doing the bore scope. Let it run for a tiny bit after finishing cleaning, then instantly do a service. Ill try update you guys tommorow, thank you for the help i really appreciate it.
I use 10-40 hi tec liquimoly oil with the oil ceramic wear and protection additive, I put close to 9 litres of oil and 2 bottles of the additive, that’s my first service ever since I’ve bought the car. I have some more ready to go for next service I’ll try doing an engine flush & try clean the bores out after doing the bore scope. Let it run for a tiny bit after finishing cleaning, then instantly do a service. Ill try update you guys tommorow, thank you for the help i really appreciate it.
make sure you are using only an SP rated oil. without cats, you can use something that has a little bit of higher zinc, but I would recommend not to use anything with a ceramic additive because it will clog your rings. It did clog my rings if you want to research my post that says cylinder walls at 72K miles.. consider that once you are starting with a little bit of blow by, the ceramic is cooking into the wrong places, ie rings.
make sure you are using only an SP rated oil. without cats, you can use something that has a little bit of higher zinc, but I would recommend not to use anything with a ceramic additive because it will clog your rings. It did clog my rings if you want to research my post that says cylinder walls at 72K miles.. consider that once you are starting with a little bit of blow by, the ceramic is cooking into the wrong places, ie rings.
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This Is the oil I use for both my m157 and my m156, it’s worked amazingly with my c63 with the adative, is there any oil you recommend for the m157, I’m just getting in the world of the engines so I don’t know what to exactly use. I’ll check out your page now.
update: just checked the page, is shows recommending using 5-40/10-50 oil either one. Not exactly sure which brand. Also seen that using engine flush isn’t good for the engine, I will definitely need to give the engine a good clean. Plus to notify youse all I will be trying to do e85 fuel, intakes, down pipes plus a little pops, I am wanting power looking around 450 to 500kw on the wheels. What should I use going from here.
Last edited by creative khal; Dec 31, 2025 at 01:01 PM.
@creative khal That is the oil I started to use two oil changes ago...and, two fresh bottles in the garage I need to get into the car. For me the engine is all around quieter since I changed from the 0-40 to the heavier weight Moly .
@creative khal That is the oil I started to use two oil changes ago...and, two fresh bottles in the garage I need to get into the car. For me the engine is all around quieter since I changed from the 0-40 to the heavier weight Moly .
my engine is very smooth, no problems (I think). Just blowing smoke from burning oil.
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This Is the oil I use for both my m157 and my m156, it’s worked amazingly with my c63 with the adative, is there any oil you recommend for the m157, I’m just getting in the world of the engines so I don’t know what to exactly use. I’ll check out your page now.
update: just checked the page, is shows recommending using 5-40/10-50 oil either one. Not exactly sure which brand. Also seen that using engine flush isn’t good for the engine, I will definitely need to give the engine a good clean. Plus to notify youse all I will be trying to do e85 fuel, intakes, down pipes plus a little pops, I am wanting power looking around 450 to 500kw on the wheels. What should I use going from here.
There are many good brands, which is why I did not recommend one. The oil solenoid thread probably has the most amount of valid oil information for our engine. I would choose the highest viscosity recommended, especially for areas that are warm all four seasons. I use 5/40-5/50 down to 0°f. I only recommended the proper grade (sp) which is determined and invented to be cleaner than SN rated oils. What the manual says is no longer valid considering technology has progressed and we see the negative consequence of SN oils in GDI engines. My negative experience with ceramic is directly with liqui-moly and blow-by on an m157. And not to be negative, but your opinion on engine flushes is not scientifically valid. There is a process to everything and for the people that can’t follow the process or don’t have the willingness to learn the proper processes, those people should not use chemicals. For those people, if it’s available for those cars (it’s not for ours), they can use something like restore and protect. And for context, I did these things to my car when the only hint of smoke was at full throttle after first start after the car sitting for multiple days, and it was not even what I would consider was a puff of smoke, so the fact that you are blowing smoke points to extremely poor prior maintenance and you need to do whatever you can before you pull apart that engine to include properly executed chemical flushes.
All, of course, in my very honest opinion
As for the number five cylinder, just Google M157 engine and number five cylinder. Lots of history there which you do not want to be a part of…
Last edited by Baltistyle; Dec 31, 2025 at 03:21 PM.
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ruins the engine.
