Hello. I am servicing my 98 z28 for the first time and need to know the kind of oil that you guys use. my manual says to use the GM brand 10w 30, but what only seems to be available is the 5W 40 Mobil brand and 15w 40 of Shell. Apparently 5W is for low temperature weather, and 15W is for higher weather temp. Temperatures are usually high where I live (approx 30 C)The last digit 30 or 40 means a higher the number the higher the quality grade. Three questions though, is it okay to use the above suggested oils?
Secondly, they say Mobil 1 is the best for performance cars. Should I go for that or would Shell be okay? Will I hugely benefit from Mobile 1 compared to Shell or BP?

Thirdly: what is the best way of servicing? Once the old oil is drained and the new oil is put in, do we drain the new oil and finally again put in the remaining new oil? or do we simply drain the old oil and put in the new one?

I would appreciate some advice. Many thanks

 

I personally use 0w30 _German_ Castrol Syntec. I'm a recent convert from Mobil 1 5w30. You will find that Mobil 1 thins out a little too much for our cars once it reaches operating temp.

Simply drain oil, change oil filter, put in new oil. No need to redrain unless you like wasting $ and oil...

after 3 months or 3k mileage, I'd get an oil analysis done to your oil to see where you stand as far as wear is concerned.

Here's a guide to oils and filters for our cars.

http://tfbm.org/faq/oil-filter.html

 

You won't really gain anything from using specific oils, you can use any brand you want.

Drain oil, replace filter, refill oil and make sure you check to see if its full or overfull.

 

IIRC, assuming you're using 5-30w, the first number (5) is the weight that the oil is when it's cold, i.e. on start-up. It is thinner that way it is able to quickly lubricate the metal surfaces since the oil tends to drain down to the pan when it isn't running. The second number (30) is the weight that the oil has after the oil has reached operating temp, when the engine should have a thicker weight to deal with the high temperature.

Check this out if you want to know more.

http://auto.indiamart.com/auto-consu...viscosity.html

People will still debate now over which grade to use, but in general you're definently not hurting the engine running 5-30 or 15-30. The problem can come from running too thick an oil (20-50), or one that grows too thin when the engine warms up (some of the lower quality 0-30s from what I've read)

 

Pull the drain plug from the oil pan and drain that oil out.
Take off the old filter and drain that oil out.
Fill the new filter with new oil.
Install the new filter good and snug but my hand only, no tools.
Put the oil plug back in.
Fill the crankcase back up with 5.5 quarts of oil thru the cover on the motor that says OIL.

 

Hey thanks all of you. Just got it done. used the synthetic BP Visco 5W40 oil. Couldnt find anything closer to what was recommended. Thanks.

 

well.. you dont want anyhting thats too thick or too thin b/c of the surfaces and hte tolerances in LS1's. our mirror smooth metal surfaces on our internals look like the himilayan mountian chain under a microscope. you want an oil with a viscosity that will fill the cracks and crevaces to make oil on oil friction instead of a thining layer that shears your "mountian peaks" and speews metal bits into your oil.
But thats just the story behind oil, if that helps you decide... private NON-ADVERTISING-influenced tests have shown that Castrol and mobil are best for antifriction and holding up to heat. But the older graded oils work best because they contain less detergants and more metal-coating additives (like the "extended milage" blends). some of those can violate your warranty--if u had one-- because it has more "enviromentaly damaging" effects and reaps about 1000 miles off your catylitic converter life. (not with every oil change!! i mean long-run life)
hope that helped..?