So I recently discovered that I had a blown head gasket on my 2012 C250, and absolutely love this vehicle. I had purchased it used with 35k miles, and at 178k miles, have finally had my first problem with the vehicle which is my blown head gasket. Had performed a “Combustion leak test” twice, and both times the fluid remained blue, and have performed 2 oil changes, and both times had drained about 7-8 quarts of oil/water out of the oil pan, and that’s after I filled the cars coolant reservoir with water, and overnight the reservoir would be near empty, and realized that the water was leaking into the engine, and I’m guessing via the “head gasket”, unless there’s any other way that water could go from the coolant reservoir/hoses, and end up in the engines oil pan when I drain the cars oil? Anyways, since I’m replacing the head gasket, I have also purchased a timing chain kit, and am replacing the timing chain, with the TC sprockets, but I have a slight problem, and need advice on how I can go about with the rest of the engine tear down, since I have removed almost everything except for anything past the valve cover coming off, because I have an aftermarket UPD lightweight crank pulley, and it does not have the the markings on it, so unlike having an OEM crank pulley, I cannot rotate it to determine when cylinder #1 is at 0 degrees, and at TDC. With the spark plug removed, would I be able to use a long screwdriver to determine if cylinder #1 is at TDC, or is there another way to check, possibly by lining up the markings on the timing chain sprockets to the TC cover, or camshaft retainers? Please lmk if there is another way, because I cannot proceed with the timing chain removal, or even replacing the head gasket until #1 is at TDC. Also I wanted to know if their is any recommended solvents/cleaners to use on the head? Would using acetone with a soft bristle tooth brush be ok to use? And are there any recommended additives/Lubes that should be applied to the camshaft bearings/journals? And any other advice is greatly appreciated. I really love this vehicle, and was surprised (and a bit upset lol), having paid extra for an Extended warranty, and never having any problems where I could’ve exercised a warranty claim on my car,
especially after having installed almost every bolt-on. Made for the M271, and now I want to keep it running since I’m planning on doing some fabrication, and can hopefully bring something functional/useful to the members on this forum. Only thing I can remember happening was the OEM alternator went out at 130k, and at that point I also swapped out the plugs, coils, flushed all the fluids, and had a dealership flush/fill the transmission fluid, and even with the racechip piggy backs, engine modifications, etc, had no issues with this vehicle, and all i did was preventive maintenance, and now that I’m tearing down the engine, I’m glade that I’m able to clean, and am wanting to replace any other parts that I should replace while the engine is apart, so any other suggestions would also be appreciated. Thank you.

Tested the combustion for the exhaust leak twice, and was negative.

Cap had some foam, which could either be an indication of a blown head gasket, or someone who drives very short commutes which doesn’t allow time for the engine to warm up completely.



Is there a way to determine TDC for cylinder #1 from the markings on the TC sprockets, and CS retainer from lining up?

Oil change gave me 2 pans of this watery oil. The pans are 6 quart pans, and would estimate that I had about 9-10 quarts since both pans I used were filled up to same Height.

Really love this car, and hope to make it into a project car.

My crank pulley has no markings since it’s an aftermarket one, so am unable to tell when I’m at 0 degrees.