Coolant looks like chocolat milk - diagnosis?

Posted by Jed Sheehan On 2010/5/23 11:13:00

I am looking for some advice in diagnosing a problem with my '56 400. I just returned from a Blue Ridge Packard tour and heard a hissing noise from under the hood. When I opened the hood I saw what looked like chocolat milk bubbling out from around my radiator cap and a puddle under the car from the overflow vent.

The car ran absolutely perfectly on the tour with no overheating problems at all. I checked the oil and, while it was at the low mark on the dipstick, it looked normal. I checked the transmission fluid and it doesn't register on the dipstick although Bob Aller rebuilt ransmission shifted perfectly during the tour.

So, I'm thinking I have a leak in the transmission cooler allowing the tranny fluid to get into the coolant system. I'm also wondering what the "chocolat milk" mixture will do for my cooling system and if I can flush it all out. And I'm also wondering if I have that same mixture in my transmission and what it could do in there. Nothing registered on the dipstick which could be a good thing (no chocolat milk).

Any thoughts or advice on what to do next?