hey i got a 98 neon 80k miles sohc. i was planning to put mobil 1 synthetic 10w 30 oil in my car instead of what i use now castrol gtx 10w 30. i was curious tho if it would be ok to run this type of oil seeing how i have kinda high mileage on my engine. i have no oil leaks or anything the only problem is i kinda have to add oil every so often cuz i guess i burn some off. i don't go low or burn it off fast its just i loose some over time. i figured it was normal for how i drive. if any one has any input before i go out and spend the money on this oil that would be great.

 

Synthetic oil has been blamed for finding oil leaks on hig mileage engines. The theory is that it the dyno oil will form hard deposits in small passages (which it does), and the synthetic oil will break down those deposits (which it should), resulting in higher oil consumption as the new stuff slips through.

The clearances on the Neon were very tight, considering when it was designed. There really shouldn't be much buildup of deposits to begin with. I switched over to full synthetic at 70k miles or so and didn't have any problems. Dozens of others have switched over higher mileage neons without issue. But there will always be those 3 or 4 guys that pipe up and scream bloody murder about the rear main seal letting go within a week or wiping all their main bearings on the way to work the next day. Dunno... anythings possible.

The most likely spots for leakage after the switch would be the aforementioned rear main seal and possibly the head gasket. If they do leak, chances are they weren't all that far from letting go in the first place.

Best of luck!

 

Just to add, conventional oils make seals swell, and synthetics, which are PAO oils, cause seals to shrink.

 

syn. oils should really and theorectically only be used when the powerplant does not have natural rubber seals. ANY type of syn oil will destry the NATURAL rubber seal. If the seal has and type of synthetic rubber in it you should be fine. That is what I was told when I was in my powerplant classes for my A.P. license.