Synthetic to Conventional

[dowsewashere]

So I changed my oil around 2,000 miles ago. I've used conventional my 15,000 or so miles with the truck. This last time I switched in her old age to full synthetic. The truck has used damn near a half quart when with conventional it never so much as used a drop...

Has anyone had this happen, I'm going back to conventional valvoline 5w30 from max life 5w30 but this is stupid.

 

[df2x4]

Never used synthetic in my trucks, but that is interesting. IMO this is a great reason for the old saying "If it ain't broke, don't fix it." My trucks have been on regular Pennzoil 10W-30 since they rolled out of the factory. Whenever they eventually require engine rebuilds I'll definitely consider switching to Amsoil synthetics, but until then they'll continue to get the yellow bottles.

 

[poncho62]

There is a theory that synthetic is able to get into tighter places than conventional, thus tends to cause leaks by seals sometimes. Going back to conventional may stop it....may not.

 

[SkyHighColorado]

your truck has problems, its for sure not the oil. fyi, its somewhat normal for 350's to burn upto a quart over 3000k

 

[rosco]

I had an old Camaro with a 305 in it years ago. I used Castrol HD 30 since I bought it. Well, there was one time it was due for an oil change. They were out of HD 30, so I went with the conventional 10W30. It smoked (literally) a full quart the first 100 miles after that oil change. I went back to the HD 30 and it never happened again. Reminded me of what my Grandpa, who was a life long mechanic, to stick with one weight oil. If you change the weight or type, you'll have issues, so don't do it.

 

[Chris6060]

Changing weight due to different temperatures will never hurt anything. (We get +30C in the summer and -40C in the winter here)
Changing types of oil and stuff, can cause small issues (burning), but burning oil is fine as long as its not smoking hard. My boss had an LS7 Corvette Z06 that burned oil from the day he bought it, never complained or had a single issue, and he abused the s*** outta it.

350's commonly burn oil, mine burned a liter of whatever I put into it, within a week, before I finally switched to a full synthetic Diesel 0w-40 made by Mobil, which it burns maybe half a liter between changes, leaks a bit of that too, so. Wouldn't recommend a diesel oil in a Vortec though, the TBI's seem to like it due to the higher ZINC content (flat tappet cam).

 

[RyanMerrick]

your truck has problems, its for sure not the oil.

^THIS

 

[RyanMerrick]

http://www.royalpurpleconsumer.com/synthetic-oil-myths/