The Stovebolt Site Forums The Shop Area Engine Shop New engines

My nephew just had his 2004 Colorado 5 cylinder rebuilt (355k miles) and the shop sent the old pistons back. I was amazed by the tiny piston skirts; probably about a half inch below the bottom of the wrist pin. I have read that they fit some new engines with such close tolerances that 5wt oil is recommended so I guess with fitment that tight piston rock is not a concern. Still scary to look at.

I know what you mean, when I pour that 5W20 into my wife's Jeep Liberty, I always do a double check on the label. The stuff looks like water!

Some cars, mostly Toyota and some Honda models, are calling for 0w20. Talk about pouring like water!

The guys that have the local repair shop, just one since population is 600, used to work at a big Ford dealer and they said the 4 cam Cobra engines also called for 0-20 but I thought I'd heard wrong.

Newer engines from all manufacturers are using the very light oils. This allows the camshafts to advance and retard quickly, and variable displacement engine lifters to activate quickly. Some will turn on the check engine light and have a code for the oil being to thick and to change oil.

Joe

After pouring SAE 30 into engines for years, I know it seem strange to be using 5w-20, 0w-20, or even 5w-40 in a diesel engine.

The reason for switching to lighter oil was for a couple reasons. One being fuel economy and emmissions. Basically, it takes less energy to turn over an engine with lighter oil.

Another reason has to do with the fact that most new engines are overhead cam, or utilize roller lifters. The tiny needle bearings in the cam followers, and lifters don't need the thick oils of the past. Not to mention, most engines utilize variable valve timing, which is dependent on oil pressure.

Chryslers. I've reset enough of those codes over the years, plus changed the oil to correct 5w20 that's supposed to be in it after the oil change place put in 10w30.