Re: Oil in Coolant

[rdh@genrad.com (Robert D. Houk)]

   Thanks to all of you for the advice. I should have mentioned originally
   that I have a 5-speed manual mixer. This tranny does not route the oil
   through the radiator for cooling. So, if the tranny oil is in the coolant
   then I *REALLY* have somthing wrong...    :-)

You may still have an OIL cooler . . . (mine -- '83 UrQ -- however is an
air-cooled oil-cooler)

   Somebody mentioned cracked head as a possibility. Is this possible with
   aluminum heads??? This is sounding more and more like something I don't
   want to hear about...

Ohhhhh Yeeeesssssssssss Al heads can crack. And do crack. Very Expen$ively,
too, I might add.

Bear in mind that for oil to enter coolant system, you must have a "path"
where the oil-pressure exceeds (first level approximation) the water-pres-
sure so that the oil can flow "into" the water environment. The entire
water (cooling) system is closed and under pressure (when hot, anyways...),
while the oil system is mixed - base resevoir at ambient ("no") pressure,
with assorted oil passages under high (much higher than cooling system)
pressure.

The head contains oil under high pressure, oil not under pressure, and
coolant under low pressure. The head contains by far more coolant "system"
than oil "system" -- it has coolant channels flowing everywhichway to keep
the head from melting, but the only oil would be one or two (?) small pas-
sages to the camshaft bearings [have I missed anything?]. As such, I would
*imagine* that any head problems would most likely manifest themselves as
coolant entering the oil system, and not oil entering the coolant system.
(But I can also imagine a reverse leak - after warming up and stabilizing,
then cooling down the coolant system may develop a "partial vacuum" [nomi-
nally the "radiator cap & resevoir" deal with this] that could conceivably
alternately "blow out" coolant when hot/under pressure, and "suck in" oil
when cooling down again. But this is pretty contrived...)

So, basically, you may have a small leak somewhere . . . hopefully just a
dead gasket . . . probably expensive, just in terms of labor to find it!

I wish you luck! Let us know what you find . . .

					-RDH