which one is better???
I am in SF bay area

 

which one is better???
I am in SF bay area

 

Do you mean which brand or which weight of oil???

 

search, otherwise thread will grow beyond your wildest imagination

 

I use Castrol GTX, 10w-30... 20w-30 in the winter.

 

Mobil 10w-30 year round

 

Why would you use 20w-30 in the winter, that means that it would be thicker on start up, and the same thickness once it is warm.

 

hey you guys.. whats the story with 15w40

i got some chevron delo 15w40 and Amur_ mentioned that it might not be good for rotaries (because of additives to get the split of 15 and 40)

comments anyone?

 

I just use Castrol GTX. My dad's used it for 20 years and hasn't had a problem with any of his cars.

 

Just run 20w-50, if your oil seals are leaking a little bit than it won't let as much oil threw. Other wise just use 10w-30, and isn't 15w-40 diesel engine oil.

 

yeah 15w40 is for our 15.9L inline 6 CAT turbo diesels.. (at work)

i didnt think there was any difference between that oil and other oil (except for the weight rating)

used to use 15w40 in my other cars with no problems

but were talking about rotary now, so im curious..

 

I wouldn't use it, I'm sure there is a special reson that it is for diesel engines, I'm not sure why it might be just as good as normal oil if not better, but I'll stick with my 20w-50.

 

i was trying to look into it at chevrons website to find out the differences, but i couldnt really find any except those "pitch ads" where people say theyve used it in their fleet for years and crap

 

There have been some people that have said that there are certain additives in it that dont burn well and that it can gunk up your rotors or something along those lines. I personally never used it so I couldnt tell you.

 

Just remove your OMP, and run premix, and you don't have to worry about that.

 

premix for me is still debateable.. from what ive learned (and using logic) the OMP lubricates the apex seals at.. the apex seals! premix lubes up the face of the rotor more i would think.. not that none of it would reach the apex seal, but still..

but so many people have been running premix w/o an OMP for over a year with no problems, so..

im kinda torn..

 

10W30 for temps between -10F and 80F
20W50 for temps between 20F and 140F

And I don't think that 15W50 would have the same problems that 10W40 and 10W50 and 5W30 would have (the extra polymers and additives to get that wide of a viscosity range with such a low base stock weight). But it should be at least a SF or better grade.

 

do i see 10w40 on that sheet? and then 10w50 (on same line)? its a bit blotchy

but my initial thought would be, 15w40 would have less crap to get the split, so if anything, 15w40 is safer and/or better than the factory rating of 10w40?

 

i used to sponsor castrol and i recommend with my life castrol full synthetic 5-50 weight. thats what i use in all my cars and ill never change

 

And see while I love and use only Castrol GTX in my cars and trucks I won't touch the Castrol Synthetic (Syntec)as the ash content is incredibly high (1.2%) and the high amount of Phosphor in the oil (.095%), both of which are proven to cause problems in Rotary engines. In addition there is less than .11% zinc which is really the minimum that should be used in the oil on extended drain cycles (5000-7000 miles).

Compare that to the regular Castol GTX with its .85% of ash after combustion or Amsoil synthetic with less than .5% ash or the Redline with less than .01%. Again the GTX has a nice .12% zinc making it ideal for high performance engines.

Castol Synthetic really is one of the worst out there as far as synthetics for a rotary go, and is compariable to the other poor quality synthetics from Valvoline and Havoline, that caused Mazda to warn against using in rotary engines.

If you are going to use Castrol, use their GTX. But if you are going to use Synthetics, use a good quality synthetic like Amsoil, Redline, Neo, Mobil1, or Royal Purple. All of which have a much better ash and zinc level and should be safe for the rotary engine.

And Black13B That sheet was done before the current oil grades and technology was developed, so yes you will still see 10W40 and 10W50 on it, even though conventional 10W40 and 10W50 oils should be avoided like the plauge. And although I have not looked much into the 15W based oils, it would make sense that the higher base stock would avoid the problems of extra additives and funky polymers that cause problems in so many modern engines.

 

Castrol GTX 20w50

 

Castrol GTX 20w50 Spring Summer Fall
Castrol GTX 10w30 Winter