to make a long story short, is it bad for your engine to go from synthetic oil to petroleum based oil? i heard that it is from some people.... i have to run synthetic 5w-40 in the winter cuz some mornings its around 0 - 10 degrees and i have no place to plug in. then im bac home for the summer in Baltimore n it gets kinda hot in the summer where i would rather run 15w-40 which is petrol based.

 

Most synthetics are compatible with dino oils now.

 

Which 5w-40 was it? It might be highly refined conventional oil even though the label says synthetic. I'm guessing its Rotella in which case I wouldn't worry at all. I've even run a rotella 5w40/15w40 blend in my bike

 

It wont hurt anything at all.

 

You can switch back and forth as many time as you wish without hurting anything. Been there done that.

 

All motor oil is petroleum based.

 

The early synthetics had a lower 'swell' rate than the non-synthetics and so resulted in instances of the oil getting past the seals. They both now have virtually the same swell rate.

 

The question in my mind is why did a pop up for synthetic oil appear on my screen?!

 

I got it...not a pop up...i'm just an idiot. Sorry!
-Geoff

 

I run a 0W40 synthetic in winter, and 15W40 Dino oil in summer. Changed every 5000 km. Most seem to think this excessive, but oil is cheaper than engines.

I have never had any trouble, I would advise against mixing the two though, complete change each time.

 

thanks guys.

 

No problem. Like I tell my kids the most important thing about oil in your vehicle is making sure you have oil in the crankcase. Next comes proper specs. and weight.

I always have customers worried about changing from one brand to another or from Dino oil to Synthetic oil etc.

I tell them "NO DON'T DO IT" the remaining dino oil in the engine will ban together and refuse to jump into the oil pump pickup. If the two oils do form some type union they may decide to take turns as to which one will jump into the oil pump pickup on Monday and which one does in on Tuesday and so on.

Really though what could be slipperier that two non mixing oils "oil on oil" that sounds like a very slippery substance to me.