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2012 mercedes s350 engine oil and coolant leak

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Old 02-15-2023, 10:20 AM
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2012 mercedes s350
2012 mercedes s350 engine oil and coolant leak

Hi, new to the group. Thanks for having me. I recently purchased a 2012 mercedes s350 and the engine was seized. The first main bearing was stuck to the crank. Long story short I sent it to a machine shop got the block tested for cracks, they put in oversize bearings new piston rings and installed the bottom half. I got the heads cleaned and checked for cracks. Everything seems to be good. Fast forward I assemble the rest of the engine myself and follow the book for all torque specs. All new parts from mercedes, I used the old head bolts but the measured in spec according to mercedes. I installed the engine and ran the car. Everything seems to be running good except its leaking oil out of the back seems to be between the engine and the transmission. I cant see any oil from the top end it just seems to **** out of the trans hole where you remove the rubber grommet. The weird thing is its also loosing coolant out of somewhere back there. In addition there's a hole that's not threaded on the front of the drivers side block just to left of where the a/c compressor mounts that's leaking oil. My uncle has the same car so i looked at his and his has the same hole no plug or anything and his doesn't leak. I called the machine shop and they claim they tested the block and it isn't cracked. I'm just wondering if i put a plug in the wrong place or am missing something. I didn't end up with any extra parts so I'm kinda stumped. My next step is remove the trans and try to see where exactly the leak is coming from. Weird part is no coolant seems to be getting in the oil pan. I was wondering if anyone has built these engines and maybe has an experience on what I can check or where to start. I'm not a mechanic but i do my own work and I'm pretty good about following the steps. First I thought the rear main seal or the balance shaft rear cover silicone didn't stick or something but i cant explain the coolant. Ive attached a pic of the block and circled the hole where the oil leaking in the front. If anyone has any ideas or experience with this id really appreciate it.


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