1999-2009 [Subscribe to Daily Digest] |
When I bought my 1991 Alfa Romeo Spider, I had done a lot of research on the car. I knew that the basic engine and drivetrain were the same as the original 1966 Alfa Romeo Duetto Spider Dustin Hoffman drove in "The Graduate". Of course when I bought the car I dutifully read the owners manual and noticed that the recommended oil was 10W-30 with 10,000-mile change intervals. I mentioned this to a couple Alfistas and Alfa mechanics and they just laughed. Their recommendation was don't use any oil thinner than a 20W-50 or the oil usage will be horrendous. Even with 20W-50 expect oil usage of 1-2 qts between the 5,000-mile oil changes.
I figured they were just old school and decided to use Mobil 1 10W-30 after the first 5,000-mile 'break-in' period. For those who don't know, the Alfa Romeo spider engine is a twin cam, hemi-spherical head, all-aluminum engine (engine block, head, pistons, etc.) with 'wet' steel liners (liners are surrounded by the coolant). The engine holds a whooping 7.5 qts. of oil a massive finned aluminum oil pan.
With 10W-30 oil, the engine would 'burn' about a quart of oil every 1000-1500 miles when used for frequent around town trips. Oil usage on long trips was not noticeable. It was just insane. Going back to the Alfistas and Alfa mechanics they pointed out that the engine design was 35 years old. Alfa was not known to have the best machining practices and tolerances. What with the deferential expansion of the steel liners and the aluminum pistons, and the engineering methods available to Alfa in the 1960’s, the piston ring gap was huge when the engine was cold but provided a nice tight seal after the engine warmed up. Switching to Mobil 1 15W-50 minimized the oil loss to around 1 quart every 2500 miles in around town driving.
So why did Alfa change their oil viscosity recommendation to 10W-30 oil in the first place?
Why to wring a couple more MPG out of the vehicle during the EPA tests, of course.
Rob Mustard (aka REM in Seattle)
1991 Alfa Romeo Spider convertible; 5-sp; 88,000 miles
1998 Saab 900SET 5-door; automatic; 53,000 miles
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