DeTomaso Mailing List: September 2000, Message #96

Richard,

Amsoil makes (or at least made) a high quality bypass oil filter. I had a 
diesel blazer that I ran synthetic oil in. I had to change the $$ synthetic 
pretty often because of the diesel blowby. After investigating options I 
added the Amsoil bypass filter. After a number of miles (more than I could 
run without the bypass filter) I sent an oil sample out for testing, and it 
came back OK.

The bypass filter (remember the old Frantz TP filters?) is supposed to take 
out contaminants much smaller than the full flow filter. It appeared to work 
on the diesel, which I'd guess is a much worse situation than the air in the 
engine compartment (my guess, no data to support). The Amsoil filter used a 
custom element that looked like fiberboard, and cost a bunch more than a roll 
of TP.

Any other experience with bypass filters out there? I forget the exact cost 
of the oil analysis, maybe $30? I also have had great performance from 
synthetics, and am equally surprised by you engine wear. I usually feel 
guilty when I drain the synthetic because it still looks good. I've used 
various synthetics in bikes, diesels, and a Volvo turbo. All with drain 
intervals much longer than recommended, and great results. 

Maybe you should consider oil analysis on the new engine at set mileage 
points? Then you could tailor the drain interval to your specific 
application.  The oil analysis also IDs the contaminants, so if you know 
what's airborne in the engine compartment, you could look for it in the oil.

Ken