For some strange reason, my LB7 that I bought in Indiana came with a catalytic converter & EGR. I took the cat out last summer & when the blocker plate craze hit the Diesel Place last year, I bought one from kroutman & installed it last winter sometime. I had an oil analysis done with Rotella T 5w-40 synthetic before I installed the blocker plate, & thought I would do another with the same oil after I had installed the plate to see if there was much improvement.

Numbers on the left are without the plate installed, & numbers on the right are with the EGR blocked.

Miles on oil: 8,195/8,023
Aluminum: 2/3
Chromium: 1/1
Iron: 12/10
Copper: 3/3
Lead: 5/2
Tin: 1/4
Silicon: 9/6
Visc@210:76.6/72.2
Flashpoint:430/410
Fuel: <0.5/<0.5
Insolubles:0.4/0.2
TBN: 6.2/10.2

AC Delco air filter & M1-303 oil filter were used during both OCIs.

Using the blocker plate did help keep the viscosity down, which has always been on the high side with this truck, & the TBN is certainly better, but I'm not convinced that the 6.2 reading was accurate, since I've never had another TBN lower than ~9 during other UOAs with this engine. Wear numbers didn't really improve, since I think any decent CI-4/CI-4+ oil can handle an EGR equipped diesel engine, & I think those numbers are pretty good for 8,000 mile oil change intervals.

BTW, I've taken the blocker plate out, since I got tired of my SES light being on, & unfortunately, a finger stick won't work on an LB7.

Interesting

I can beleive the 6.2 without the plate. The EGR is open mostly at idle and the extra heat can cause the oxidation to go up and when it goes up so does viscosity. What are the oxodation numbers?

I just changed oil yesterday and put in the blocker plate (no ses yet) and we will see what happens. Had 17.5K miles on the oil. It was still in good shape but I to wanted to test the blocked plate to see what effect it has on the oil.

Greg

I can beleive the 6.2 without the plate. The EGR is open mostly at idle and the extra heat can cause the oxidation to go up and when it goes up so does viscosity. What are the oxodation numbers? The reason I wonder about the 6.2 TBN is that all my other UOAs have never had a TBN lower than 8.5 (average is 9.1). But I should also say that the 10.2 TBN with the plate installed is the highest TBN I've ever had at an 8,000 mile analysis. And Blackstone doesn't provide any oxidation numbers, so I can't help you there.

Could that be a California truck? My federal truck doesn't turn the SES light on w/the blockoff plate.

Could that be a California truck? My federal truck doesn't turn the SES light on w/the blockoff plate. On the window sticker, it says my truck was originally delivered to a dealer just outside of Chicago, so I presume it was dealer traded to the dealership I bought it from in Indiana. I wonder if vehicles delivered to the Chicago area have to meet tighter emission standards. My build sheet in the glove compartment doesn't have any RPO codes that match California, NE, or Federal emissions, so it must have some other emissions code that I haven't been able to find & match yet.:confuzeld