What single item is the most important engine wear

[Cutehumor]

the most devasting to an engine

1) antifreeze leak into the engine = sludge
2) leak in the air intake/filter = dirt
3) driving with superlow oil in the engine (1 qt in 6 qt cap)
4) cold starts with short trips. 1-2 miles = sludge

 

[Matt89]

I think it also has a lot to do with the driver. IE my mother who jumps in, turns the key and floors it can't be good for an engine.

 

[Cyprs]

I agree Matt89, I believe the "magic heat pedal" (my favorite phrase learned from Bitog) is culprit considering high wear metal zone is when oil temps are below 160F, how one consistantly/daily drives after starting our engine in this heat range is large factor in engine life IMO.

Cyprs

 

[Steve S]

The airfilter, run your car without it and see how long your engine lasts .

 

[andyd]

Air filter. I suppose, follwed by a reasonable OCI interval. Oil is pretty much equal in performance, if the OCI is proper to the oil. Checking the dipstick occasionally isn't a bad idea either.

 

[Scott_Tucker]

What 'dirt' gets in the engine oil anyway?