Considering switching from a 10w30 to 15w40 (Delvac, Delo 400 or Rotella T)during the summer since my oil consumption increases in the summer as well as to hopefully lower the amount of engine clatter (valve train?). Anyone have any negative experiences using the diesel oils? Other suggestions welcomed.

 

I've used Delo 400 15W-40 in older, higher mileage cars and it's outstanding. I think it works better than a synthetic in that application because of the reduced tendency to leak past seals. It'll help reduce engine noises and should reduce consumption.

One thing I noticed, though, is that it's a very high detergent formula. If you haven't run it before, I'd suggest changing the oil and filter after 1K miles of Delo. It's so effective that the filter could clog, the bypass open, and unfiltered particulates would circulate doing more harm than good. Of course that means using an OEM Toyota filter with a properly calibrated bypass valve and anti-drainback valve. My 2¢.

 

Ok, I have been reading through many MANY threads on what weight/brand/ type of oil to use for high mileage engines .... never got a very clear answer so my question is: What weight is best .... synthetic or dino? OPINIONS WANTED PLEASE!