Re: Oil in coolant - 2 litre

[Scott Fisher <sfisher71@domain.elided>]

--- David Masters <david@domain.elided> wrote:
> Fellow Alfisti,
> 
> I had the sickening experience of finding emulsified
> oil in my overflow tank on the mighty 2l Twin Spark 
> over the weekend.  

Caveat: the lore I'm about to pass on is for
single-plug 2L engines; I don't know what other
advances may have been made in the Twin Sparks, but
I'm sure I'll find out...

I had my first exposure to this three years ago, a few
weeks after purchasing my '74 Spider.  Flushing the
coolant, using a proper water/glycol mix for the
climate (60% water/40% glycol) where I lived at that
time, and replacing the oil with a higher viscosity
took care of it then, and I haven't had a repeat
since.  I've taken to managing the condition of my
coolant pretty aggressively, but haven't had any
further problems (except the first drive after a shop
replaced my coolant with one with too high a
concentration of glycol for 100-degree-plus
operation).

In other words: you can probably relax, but not all
the way. :-)

> Refilling it with new Coolant, there is now no
> evidence of there ever being a problem.
> What are the leading causes of oil getting into the
> coolant, and are any of them repairable? 

The problem is in the oil passages between the block
and heads in 2L Alfas.  There's less metal around the
oil passages than in earlier engines due to the
increased piston size, and the 2Ls (at least the
single-plug engines) "all do that" to some extent.

There have been improvements to the O-rings used to
seal the oil passages since the early 1970s; if you
replace your head gasket, be sure to check for the
"new and improved" (material at least, and shape too? 
I can't recall -- it's one of those things I know I'll
need one day but don't need YET) O-rings when the time
comes.  For now, though, let's see if the time can be
put off a bit, if the rest of your engine is still
strong.

And that's the best news: a once-in-a-blue-moon trace
of oil in the coolant is not necessarily a sign of
disaster in a 2L Alfa.  Fortunately, oil in the
coolant is not nearly so dangerous as coolant in the
oil.

However, you should monitor this for a number of
reasons.  First, of course, is simply that this may
NOT be as benign a symptom in your Alfa as it was in
mine; like finding lumps under the skin, sometimes
it's a mosquito bite and sometimes it's more serious. 
So you should get in the habit of checking your
overflow tank regularly, at least once a week and more
often in hot weather.

In addition, I've heard it suggested that the presence
of oil in the coolant will cause rapid deterioration
of the cooling system hoses (the rubber softens in the
presence of oil), which can lead you to a potentially
expensive breakdown.  If you don't know how long your
car was like this, you may want to consider replacing
all the hoses as a preventative (or more likely,
"pre-emptive") measure.

> There is no sign of any
> oil contamination in the sump.

There usually isn't (assuming you mean coolant
contamination in the sump) -- oil pressure being much
higher than coolant pressure, the typical leakage goes
only one way.  

One thing I did that I attribute to helping (whether
it does or not will no doubt be the source of endless
debate by those who allegedly know better; meanwhile,
I'm going to keep doing what works): dumping the
lightweight oil that was in the car when I got it and
replacing it with Castrol 20W-50.  I've found that,
for whatever reason (viscosity, additive package,
Motor Oil Voodoo, I don't know), Castrol 20W-50 has
demonstrated more resistance to seeping past seals in
older engines.  It's my "house brand" for that reason.


> I can't help thinking it is a head gasket that would
> let oil into the coolant, but it might only happen 
> under high load conditions.

Not entirely high load (though the higher oil pressure
at high RPMs will contribute).  More important, this
probably happens under high heat, allowing the oil's
viscosity to thin out, particularly if the head gasket
is older.  If the temperature gets very high, the
metal expands AND the oil thins out, leading to an
increased ability for high-pressure oil to seep into
the low-pressure cooling system.  Which brings me to:

> Any comments?

100,000 miles -- is that on the original head gasket? 
Might be time to start saving up for a replacement
anyway.  I think that 100,000 miles on an Alfa 2L head
gasket may be some kind of record...

--Scott Fisher
  Tualatin, Oregon
.
Yahoo! - Official partner of 2002 FIFA World Cup
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