Would it be safe to use 0w40 Mobil One in an LT1? I ask because I can get it for free at work.

 

It is better them 5w30 in most lt1. I have been using it for the past 15000 miles. It is a little thicker, which makes it a got choise for higher mileage lts.

 

Yes that is a better oil than the 5w-30 Mobil and a good oil according to PAtman. I ran it for one oil change before I switched over to the German Castrol 0w-30.

 

Sweet, thanks for the replies.

 

But a 0w40 oil is going to have a lot of additives in order to achieve that 40 point delta. It should be fine as long as you don't run it until it breaks down, or put it under too much stress which would cause breakdown.

 

I usually change my oil every 2K so I should be ok.

 

i was just going to ask that question also because it just came into work and this was the first time i have seen it, i think i am gonna give it a try

 

I have seen Mobil 1 go for 14000 + miles with no trouble. yes, they tested the oil every few thousand miles. You do, by the way, have to change oil filter at every 4.000 mile and top off the oil. There is no need changing you oil that soon. It is a waste of money and can be harmful to the engine. You can run 8000 miles with one filter change with no troubles..

 

You do NOT need to change your oil with this M1 0w40 every 2,000 miles...Unless you're mostly dragging it...If it is a daily-driver that you occasionally get on it, it can go much longer than that. Otherwise, you're just wasting oil that is still good and not to mention $$$ (if you ever have to pay for it).

BTW, M1 0w40 is much better than M1 5w30 or 10w30...If I wasn't using the German made Castrol Syntec 0w30 (which has tested out a little better), I would probably be using M1 0w40...

Mike

 

I just put in some M1 0W-40 this weekend. It is indeed a very good oil. Being spec'd for a couple German OEM standards, I think it's ideally suited to an aggressively driven street car, and yet it can handle 5000+ mile oil change intervals.

I am using German Castrol 0W-30 in my Caprice and I'm going to run it for 7000 or more miles...the next oil change after that I'll put in some M1 Truck & SUV 5W-40, which is an even better oil than the 0W-40.

 

To all of you that are saying M1 0W40 is much better than M1 5W30, what are your reasons/evidence? I'm not trying to argue, it's just that I would consider changing but would like to find out exactly why first.

 

I was running the 0-40 M1 for a year or so. Went to do a oil change a couple of weeks ago and no one carries it any more ( O'Reiley's, Autozone ). They said it was being phased out So i went with the 5-40 which was plentiful.

 

That's not true. The confusion may have been due to the new API standard that has recently gone into effect. We went from the "SL" standard to "SM." The SM 0W-40 is the new bottle style.

For me, I read on the BITOG Oil Forum that the SBC (including LS1s) "prefers" a heavier weight than 30. This comes from people doing used oil analyses and seeing lower wear metals in the thicker oils. M1 0W-30 (at least the previous SL concoction) has a 100°C viscosity that is on the low side for a 30 weight. It's a good oil, just a little thin, especially for harder driven cars. Fortunately, the oil system is good enough that I don't personally think it matters. 0W-40 makes me feel better. It's also better because of the "0" rating. This means it has a lower viscosity than the 5W-30 at really low temps (we're talking -45°C here though). 5W-30 has also not passed the various rigorous european OEM standards from Mercedes, Porsche and VW. They are high temp/high rpm durability tests and extended drain interval tests. In short, the "European Formula" on the side of the bottle is no BS.

 

Can you also get a free short block?

There has been LOTS of talk about which oil to use on this site and I don't believe that trend is going away anytime soon.

But...this is just my opinion: 0W is a really thin oil and even slicker if synthetic. Most damage is done on initial start up and at high RPMs.

Granted, thin, good quality oil that won't break down at high temps would seem to be the ideal. I don't believe the LT1 runs all that hot and I have seen a lot of engines (on this site) that have spun bearings, etc.

There is alot of hype out there about which oil is the best, but obviously there are lots of different opinons too.

I am currently using 10W-40 Dino juice. I switched from Mobil 5W-30 after a few problems with spun bearing and valve train (I believe that my lifters might have been bleeding down too fast with the thinner oil.)

I can guarantee you that most, if not all my fellow Z guys will disagree with my assessment, but seeing cars on the road with tons of miles on them and all they used was 10w-30/40 oil accompanied by timely oil and filter changes and no problems prompts me to assume that they must be doing something right.

Just food for thought.

 

The M1 synthetic oils tend to be thinner in my experience than dino oils of the same weight. If this is true and I'm just not thinking wrong based on my limited experience, then a 40w synthetic might be very close to a 30w dino... do you think? I haven't compared the two. I tried M1 30W synthetic in my truck once and the valves knocked. Now I can't explain exactly what was going on but the engine in that truck is very strong and has never done that with dino oil.

PS That experience with my truck was in South GA during summer.