Synthetic oil for I-5s

[benswann at comcast.net]

Dave,

I have had nothing but positive results using Castrol Syntec 5W50 year round
for over 10 years.

For non-synth Castrol 20W50 has been good, perhaps a good idea to switch to
10W40 in winter.  I have had problems with viscosity breakdown on other oils
even other brands of 20W50 where the engine runs hotter and the oil pressure
switch trips because oil thins out even in under 1000 miles of driving.

Ben

[From: David <duandcc_forums at cox.net>
To: quattro at audifans.com
Subject: Synthetic oil for I-5s
Date: Tue, 19 Aug 2003 9:13:53 -0400

I've been running 20W50 dino oil in my CGT and doing MMO treatments before
oil changes. I was thinking of switching to synthetic for it's cleaning
properties and to help keep oil temps down (in high speed/agressive driving on
 the highway my oil temp goes as high as 150*C, cruising is around 130*C and in
town around 90-100*C). I realize there is a chance that the synthetic will
clean out the engine so well that it will begin to leak or burn oil. My plan
was to switch to synthetic for 6 months or so to clean it out then switch back
if it leaks or consumes oil. So, what are your thoughts on this?

What weight is appropriate for I5s? Is it available in 20W50? Do I even need it
that thick with synthetic?

Dave
2002 Jetta 1.8T (hers)
1993 RX-7 R1 (weekend play toy, soon to be for sale)
1987 CGT Special Build 2.3
in SE Virginia]