Flushing oil accidently added to coolant res.
 

1991 300SE Replaced w/pump, no leaks, Little old lady I got it from accidently put qt.oil in coolant res., flushed, but still oil, am flushing again as we speak. Idles for a while then won't restart, like flooded or gas starvation, could be sensor trying to shut it down. Ran it w/just water to flush, didn't want to restart. Gonna let it cool overnite & finish flush & refill to propers. Found loose vacuum line under reservoir while replacing bad hose, no idea where 3rd line goes. Engine shimmys, but all parts tuned, bad motor mount bushing? Is fine auto, 3rd owner, but hopefully no real issues. I am not afraid of this used auto, just concerned. BTW, no coolant in oil, no excesive oil usage, no leaks, may have a keeper. Any words of comfort? Thanks-JW

BTW, symptom of head gasket failure seems to be oil in coolant, clean oil in crankcase. But, just to clean cooling system, Tide detergent in water is recommended system flush. May need several repeats. If oil is in the cooling system any length of time, expect failures of hoses and other rubber parts. Once system is clean, it's best to replace them all.

I don't know why oil in cooling system would itself cause no-start or rough running, but then I'm not familiar with the S.

Steve

Found bigger problem...
 

Have coolant in oil and steam coming out of exhaust pipe. Gonna pull the head tomorrow. If no cracks in head or block gonna replace gasket and hope for the best. Will I have to remove the timing chain for this? Had put on a new water pump recently and wasn't that bad. Have done this type of work before (78 Corvette) but not a M/B. Can anyone refer me to a thread that covers this in detail for the 91 300 SE? Thanks in advance.

Will get a manual...
 

Please tell me that it is nothing like 71Rcodes 95 E320. Right now I am hoping for a simpler removal with no signs of warping or cracks. BTW, which is the correct torque, 54 or 41 lbs.? I am sure the manual will tell me, but that won't come til tomorrow. Thank You for a great site and informed advice. I won't forget this.