Diesel Oil Additive

[ftm1776]

I would like to use an oil additive to boost pressure a bit, especially during the hot weather. I'm using Delo 400 15w-40. Pressure has dropped after 300,000 miles. I'm not interested in any "magical potions". Or could I just add a "weightier" single grade???
Any suggestions??? I might try a heavier single grade if I could find one. Are there any precautions about doing this???
Comments, please.

[ORCoaster]

Doesn't Delco make a straight 40W oil?

[mtrans]

on hot weather...
how about 20w50 or for real hot 20w60?

[Dakotakid]

Just out of curiosity, how much of a pressure drop are you having and what sort of pressure gauge are you using to determine?
And, where on the engine are you measuring it?

I mean, is this a real problem or.....imaginary?

If the cam belt has been run too tight and you are flaking the front int. shaft bearing and it is accumulating behind or in front of the pressure relief valve in the oil pump, and leaving the pressure valve somewhat open.....well, running a heavier oil may actually aggravate the problem more as the initial start up will shove that pressure valve open even more. And then, the valve will not close all the way and will result in lower oil pressure.

Generally, decreased oil pressure in these engines have their "roots" in the int. shaft bearings...at least initially.