I suggest you use oil that has the proper amount of ZDDP which is a combination of Zinc and Phosphorous.

AFAIK almost all non-racing multiweight engine oils DO NOT have enough ZDDP as it has been determined that ZDDP is harmful to catalytic converters and has been almost completely eliminated from those oils.

You can buy an additive, but most manufacturers of 30w engine oil still put enough ZDDP in their oils.

We use Napa 30w which is manufactured by Ashland in Texas who makes Valvoline. And I took the time to verify with Napa that the amount of ZDDP is suffcient for normal street driving. Napa did recommend higher levels of ZDDP for high performance engines.

The camshaft and lifters will suffer premature wear if you don't use an oil with enough ZDDP.

Less than 2 years ago we rebuilt an engine for an 1800E. The customer did his own oil changes using Mobil 1 and did not use an additive. About a year after the engine was installed, we had to change the camshaft and lifters due to massive wear. I should have taken pictures, but I returned the camshaft to Isky for analysis and my salesman said the camshaft material was not to blame.

He now uses only VR1 Valvoline racing oil which has tons of ZDDP.
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Eric

Hi Performance Automotive Service (formerly OVO or Old Volvos Only)

Torrance, CA 90502