I was having a problem getting a plain mineral engine oil for my truck so as a stop gap I used a semi synthetic,problem was the oil pressure dropped by nearly 15psi!
Fine when cold but as the temperature rose it was getting dangerously low at idle.

I rectified the problem this morning with 'proper' oil and a new filter for my engine,I'm pleased to report all is back to normal...

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.