Hernando wrote:
> I heard somewhere (maybe here?) that the use of synthetic oils in older
> cars, my '73 TR6 in particular, may lead to some damage. I remember
Didn't we just go through this? I'm sure that I last heard the rumor on
b-c. Anyway, I was at the time in the process of trying to decide
whether to make the switch to Mobil 1. I took the seemingly unusual
step of calling Mobil and asking them.
Just so it's all in one place (in case anyone ever looks in the
archives) here's the sum of what I found out:
When Larry Colen took the engine-building class taught by Dema Elgin,
the Redline rep showed up as a guest speaker one evening to tell them
all about oil technology. Larry specifically asked about synthetics
in older British cars (Dema Elgin, Formula Fords, Cortinas, you get
the picture). The RedLine guy said that the problem stemmed from
early batches of Mobil 1 that didn't have the sealswell in them; this
caused the seals to shrink, not dissolve, but with equivalent results
as far as spewing lubricant goes.
The Redline Guy (TRG?) said that Mobil had addressed this in subsequent
batches of their product; since he was saying something nice about a
competitor, I figure it's probably legitimate. He also of course said
that Redline oils had been used in various British race cars for years.
This didn't satisfy my. I looked at the bottle of Mobil 1 and found a phone
number: 1-800-9MOBIL1. I called.
The guy asked me very carefully about the proposed use: in my case, an engine
that hasn't been taken apart since 1967. Bottom line - they didn't
recommend I switch. Basically what they see is that seals and gaskets
that old have started to harden and crack, and are sealing mostly
because of deposited sludge. A synthetic oil will clean the sludge from
the engine, and then start to clean the sludge away from the seals. And
then it will start to leak. And then people will call and complain that
Mobil 1 ate their seals.
The general rule seemed to be that if you have oil consumption due to
leakage or burning, switching to Mobil 1 (or any synthetic). will
increase that consumption. Whatever it is about synthetics that makes
them cling to metal better also makes them find cracks better.
If you've switched, and you don't see increased consumption, keep right on
using it.
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