What causes oil consumption change when changing oil types?

[doitmyself]

In a few posts several weeks ago, several members talked about increased oil consumption in their engines when they changed to a particular oil weight/brand/type. John Browning had problems with John Deere plus 50 and Buster had problems with M1 EP (went away eventually?). Another said they had problems with GC.

What causes this? And, one site I visited claimed that after two or three OCIs, the problem usually goes away. Is this true?

Thanks.

 

[luvs2drive]

Here are some reasons for oil consumption. With regards to switching brands, a thicker oil may cause too high an oil pressure.

http://www.performanceoiltechnology.com/motor_oil_consumption.htm

 

[GROUCHO MARX]

It's burned off in the combustion chamber.

 

[doitmyself]

Great article, thanks. At the beginning, it states:

"The balance of the problems are all mechanical and have nothing to do with the choice of motor oils."

So, according to this article, the real problem is the engine, not the change of oil type. So, some oils must be able to "accomodate" defective engines better than others by having lower consumption?

 

[Jeffrey]

I don't mean to take this thread in a sideways direction, but I wonder how much consumption is actually oil leakage from an area that is not easily noticeable.

For about 2 years now I thought I had a consumption problem in my Dodge Neon. It did appear to vary with different weights of oil. Recently I had to pull the crank pulley from the car. While inspecting the crank snout I noticed that the front crank seal has a slight leak, not dripping, but perhaps just weeping a bit during operation.

I intend to monitor the amount of oil loss. I will put in a new seal this summer and then check to see if my "consumption" problem goes away.