Oil in Coolant?

[1991 300SE Owner]

My 91 300SE died on me as I was pulling into my garage. When I was driving it home from the gas station, I noted that on the dash the ABS and whatever the light is next to that were on. It has been about 6 hours since this happened. I went down to the garage just a few minutes ago to check on it. The interior and exterior lights work, but the engine won't turn over except for maybe 1 time. It is also stuck in park. I looked the coolant overflow and it looks a little yellowish in there. Could that be oil in the overflow? Would that make the car totally shut down? It did not shake or anything, it just stopped. It was perfect timing since I just happened to pull into the garage.

[oldsinner111]

check transmission oil to see if milky. The built in radiator transcooler have been known to fail,head gaskets to one these engines can fail,when over heated.I run lower thermosat a 170F .Plenty heat for winter.
If transcooler try changing fluid after buying a external trancooler, or new radiator. Good Luck

[duxthe1]

The alternator has died, maybe just a voltage regulator will revive it.

[1991 300SE Owner]

I did some research online and I think it is the alternator as well. The last few nights I drove home from work the lights on the dash were so dim I could hardly see it. From what I read, that is a red flag for an alternator failure. I'm guessing I probably drained a lot of power from the battery.

I'm glad this happened when I was pulling into my garage. It was perfect timing. I have another vehicle so I will tow it into the shop when I can. I still can't get it out of park. Any ideas how I can get the thing into neutral?

[duxthe1]

Key in the on position and foot on the brake should be all it takes to get it out of park.

[1991 300SE Owner]

Thanks again duxthe1. I wonder why that would not work last night? I guess maybe because I was a bit frazzled!!

[pawoSD]

Having it die as you pull into the garage is quite lucky!

I second the bad voltage regulator or alternator. Its probably the regulator making poor contact from worn brushes as if it had completely failed it would have run out of juice/stopped running much sooner than over a period of multiple drives.

[Ferdman]

Remove the voltage regulator from the back of the alternator and check the length of the brushes. They are probably worn down to nubs. If so, replace the voltage regulator and you should be good to go. Also, you will need to recharge the battery or use jumper cables to start the engine.

[1991 300SE Owner]

Thanks again everyone. I took it into the shop on Friday and it was indeed the alternator. Yes I was very fortunate that I happened when I pulled into the garage. The only place better than my garage would have been if it happened when I was going to the mechanic shop for something else.

We charged up the battery at the shop and hooked up a voltage meter, but after a very short time the meter took a nose dive. At least now I know what the signs are if that should happen again (dash board lights getting dim).