re: oil in coolant tank

[Jay Negrin <jmnegrin@domain.elided>]

Seems that oil in the coolant tank can come from several places, not
just engine oil in the wrong place.

1 - Could be soluboil (may be a trade name) that is used to lubricate
moving parts in the cooling system (like the pump, for instance).  At
least radiator shops used to use the stuff.

2- might not be oil at all, but some sort of coolant lubrication
additive, either put there by the coolant mfg, or someone else (see #1),
that has come out of suspension, or decomposed into an oily sludge.

3 - if the car is an automoatic, it is possible that there is a trans
cooler incorporated into the coolant radiator.  if this leaks, it will
be trans oil that gets into the cooling system, not engine oil.

4 - IF it is engine oil, it could come from a head gasket which has lost
its integrity or (horrors!) a cracked head.  Either way, if it is engine
oil, a possibility, then it will have to be properly dealt with.
Best o' luck
Jay Negrin
ARO So Cal

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