UOA with bypass filter - additive loss?

[smsag04]

I have read that filtering under 3 microns can strip VI improvers and antifoam additives from oil. Does anyone running Franz or Amsoil bypass systems test for viscosity at 100F and 210F or test for defoaming?

 

[Doug Hillary]

Hi,
smsag04 - By-pass filter additive loss? I have used centrifige oil cleaners (by-pass) over many millions of kms and on a number of engines. These filter down to <1 micron and in the hundreds of used oil analysis I have stored over many years there was no evidence of "additive loss" due to filtration!

 

[D-Roc]

Haven't noticed anything in my used oil analysis.

 

[LateArrivalforLSU]

Negatory ghost rider.

 

[Gary Allan]

George of CLS reported this side effect of ultra fine filtration. Although he gave his testimony (he apparently designed the filtration systems for his customers that had found UOA showing different visc after the installations), he's shown no real data to my knowledge. That is, the before and after installation used oil analysis were never listed. Many, as you would imagine, were skeptical of the view. Schultz, of PALL filtration, offered that a molecule of anything in oil would have to be HUGE to get snagged by a filter.