german castrol syntec is not available to everyone, including where i live. We do have access to 5w50 mobil. If its like their thinner 5w30, should be like a 0w40. Mobil 5w30 is more suited motors with tighter tolerances, like my '05 sunfire

 

When I switched to Castrol Syntec 0w30, I notice that everytime I pull my valve covers, I smell fresh oil and everything is nice and clean, when I used other oils I would always smell a hint of burnt/old oil and my new front cam bearing had wear signs with mobil 1.

However, anyone notice that in the last 6 month castrol syntec 0w30 is no longer a green oil like it used to be? What did they change? Hmm...

 

Yeah, it is differant. I just can not find the German blend around here anymore. Maybe that is what you are seeing.

 

They aren't importing it anymore is what I read.

 

I heard that is typical with oils from Pennsylvania. They have a parrafin base in their molecular construction. It turns to wax (i.e. sludge) when it is burned off. It's an excellent friction modifier, but can lead to a thick, gooey sludge if not changed regularly.

 

yea they have changed from green to the gold. Suppodly on all the oil tests I seen there really close on perforamnce. If your going to use MOBILE one for an ls1 please use 40weight the 30weights tend to thin out. Mobile one is a good oil not the best but good. GC 0-30W is hard to find, but also a very good oil and most people think better than M1. Just be sure to get the german and not american. Amsoil is very excellent oil.

Good Luck.

 

the synthetics are all very good but it goes by preference. we could argue for days on what is better. quaker state and pennzoil used a pariffin base in thier oil(i don't know the cuurent oil though) this is a good additive that will hold up fine IF you change it regularly and don't overheat it. i would or do not recommend it to people with high performance cars that are going to be beating on their cars and getting oil temps high.
with sonme of the newer cars that have a aluminum blocks and heads the inside temps of the surfaces are also greater (use a temp gun and check the aluminum versus cast once) staurns and some old caddy engines are pretty bad at coking the oil inside(even mobil one)
it is recommended to use fully synthetic on all these especially saturns for oil useage.

i would use teh 0w30 in the colder chicago winters and 5w30 or 5w40 in the summer. use whatever brand you like because they are all so close. i know the amsoil seems to be the best for hp. free hp is cool. but getting it is as hard as german oil in some places. so good luck

 

There is a Mobil 1 5w50 blend available for "performance motors", its pour point is -51 which is actually lower than the 5w30 blend (-40). At any temp over 0 degrees, the 5w50 is much thicker than the 5w30.

 

I too dyno tested Amsoil back to back with Mobil 1. Amsoil showed NO DIFFERENCE.. my car actually can repeat numbers quite well rarely showing more than .3 difference btw pulls.

I concluded that Amsoil is best if you like to pay for the shipping and not have to go out shopping for oil.

I am at 87K miles now and have been using Mobil 1 ever since I finished my tests back at 13K miles. I have had no issues.

 

Mobil 1 5w-30 Synthetic is the way to go.

 

I switched from mobil 1 5w30 to 0w30 castrol and my valve train is noisier. I've tried about everything but Amsoil. Seriously, who on these boards is going to go 15,000 miles between oil changes? As I said, I've used most all of them and I don't have a bit of sludge. My engine is clean. I don't waste my time looking for any particular brand of oil any more. But I won't use the 0W30 castrol again.

 

Why are you running 0 weight oil? Even in Canada, 5 is about as low as you go (unless you live way up north near Alaska)

 

I'm sold on amsoil 0w-30w..have run it in many vehicles 91 454 burban ran it over 200,000 miles on 0w30, 91 roadmaster 350 210,000 miles, 95 roadmaster 196,000 , 95 caprice 139,000 all on 0w30 amsoil..

i remember changing the roadmaster to 0w30 at about 8,000. went from 24.5 mpg tp 26 mpg...
love the stuff
i run the HD diesel and marine amsoil in my cummins 2500 turbo..

 

I wouldn't do 15k, but based on this long term study, I don't think 7.5k is a problem with a quality synth:

http://neptune.spacebears.com/cars/s.../oil-life.html


I scored some GC 0w-30 and used it on my last change. Not because I "need" 0w down here, but because GC shows excellent UOAs on bitog, always highly recommended. I've heard a lot of wear occurs at startup, so an oil that flows quickly to the bearings probably helps. In the case of GC, certainly doesn't hurt.

 

Ever thought of reading the owners manual and use the GM recommended oil??????