Add transmission fluid to engine oil?

[DMZ]

Originally Posted by bronsin

In my experience the engines Ive owned that Ive taken apart to rebuild (VW Beetle and Bus) were just tanned a little inside the crankcase. No buildup, sludge etc at all. I changed the 2.5 quarts of oil every 2000 miles and commuted to work 30 miles away.

I dont know what to make of sludge buildup in the engine. They claim to have changed the oil.

Now that I drive my Yaris 3-4k miles a year with mostly 6 mile trips the oil comes out clean every six months...

I agree. Sludge build up?????

I am old enough to remember the days before non-detergent oils. Those old paraffin based oils would build up sludge under the valve covers and in the oil pan. I was like a thick, black grease and would eventually impede the oil circulation in the engine. That is one reason why those old engines rarely went 100k with our a re-build.

I have pulled many a head on more modern engines with a lot of miles and have never seen sludge. I have seen black/brown residue on engine internals, but never what I think of as "sludge."