Over two decades ago I walked away from Castrol GTX Oil and religiously used Valvoline VR1 Racing 20/50 for its ZDDP levels.
Well, the Valvoline seemed to vanish from my local stores and this Castrol GTX "Classic" appeared in my local Walmart so, I purchase 16 qts.
It states it's designed for my flat tappet cam engine. I called Castrol and the rep told me it had 1400 ppm of Zinc.
Sooooo, few days ago out comes the Valvoline VR1 Racing oil and in goes the Castrol GTX Classic.
I notice coming out of the bottle the Castrol GTX Classic seems more 'sticky' or 'clingy'
Within 20 some miles with a good amount of idling I noticed my 'at Idle' psi was down to 20psi.
That NEVER EVER happened before... yes, it comes-up with RPM.
Could it be a coincidence or, was the Castrol GTX Classic 20/50 a bad choice?
Well, the Valvoline seemed to vanish from my local stores and this Castrol GTX "Classic" appeared in my local Walmart so, I purchase 16 qts.
It states it's designed for my flat tappet cam engine. I called Castrol and the rep told me it had 1400 ppm of Zinc.
Sooooo, few days ago out comes the Valvoline VR1 Racing oil and in goes the Castrol GTX Classic.
I notice coming out of the bottle the Castrol GTX Classic seems more 'sticky' or 'clingy'
Within 20 some miles with a good amount of idling I noticed my 'at Idle' psi was down to 20psi.
That NEVER EVER happened before... yes, it comes-up with RPM.
Could it be a coincidence or, was the Castrol GTX Classic 20/50 a bad choice?