What oil are you using?

[SteveC]

Something else for me to consider that you already mentioned is that I'm only buying engine oil. I have no plans to run Amsoil in any of the gear boxes or differentials. I already have a routine that works for that stuff. Plus I've found that dino oil works best on differentials, even your gear manufactures and positraction manufactures don't recommend synthetics in their diffs "AT ALL"

Apparently Eaton claims the synthetics are too slippery and won't allow the clutches to lock up properly. Two of the gear manufactures I like to use (Richmond and US Gear) don't recommend synthetic for their ring gears, and if I recall it has something to do with the oil properties aren't formulated for the high stress these gears see, but my memory is fuzzy on that.
On a side note, I've dealt with a local differential guy up the street from me over the last 3-4 years. He's been building them since the 60's, been around a long time. He won't warranty any diff that goes out the door unless you run good ole fassion dino gear oil with a G5 rating. He is completely against any synthetic in a rearend, which falls right in line with what I've been told from Eaton and Richmond.

I suppose if you run a locker of some sort without the use of clutches it wouldn't matter, but there is still the issue of the ring gear though. Something to think about.

I have a Zexel-Torson unit in Sara, and I run 85W-140 dino oil in her rear end.

The shop that did the gear swap (Pro Gear) cautioned me NOT to use synthetic oil with ANY LSD.

Now in my 2013 Yukon (non LSD) I run 75W-90 full synthetic oil.

[98TransAmWs-6]

I use vavoline synthetic in my rear 75w90 I believe it is with the LSD additive but mine is the stock rear end atm I might switch back once I get my Dana S60 unit. I switched to it a couple years ago without any issues in fact it seems to run better than it did with Dino oil.

To each their own though but I am not trying to start a synthetic vs Dino oil debate. Whatever you use it is important to ensure it is high quality regardless especially if the car is put under stress or a heavy load meaning hard driving or racing conditions where a lesser oil wouldn't hold up under that load properly.

[98ramairguy]

I always use amsoil in my Ls1. I only drive it in the summer so I go with 15w50, my car has 70k on it and Ive always used amsoil and it still runs like its new.

[98TransAmWs-6]

I always use amsoil in my Ls1. I only drive it in the summer so I go with 15w50, my car has 70k on it and Ive always used amsoil and it still runs like its new.

I have been thinking of switching from the 10W 30 to something heavier since I only drive in the late spring and summer months and only a max of 3k a year on it, usually only about 1k miles though.

[98ramairguy]

I have been thinking of switching from the 10W 30 to something heavier since I only drive in the late spring and summer months and only a max of 3k a year on it, usually only about 1k miles though.

I highly recommend the Amsoil. It's not cheap but its pretty much the best oil you can get. Try to find a friend with a dealer license and you can save a bunch of money. My work has one so I use their membership to order at a good discount

[98TransAmWs-6]

I am a dealer and I use amsoil lol. I was just thinking of switching from 10w30 dominator racing oil to their 15w50 weight of the same oil.

[kingls1]

I will play devil's advocate here...

Does it really matter at this point about oil? These cars are pushing 12-15 years old now and it's likely any other oil that has been used for that long has already did whatever it was going to do. If you haven't seen an issue yet, you probably aren't going to.

No?

i would have to disagree with this also as with my car having 124k on it it was 100% stock when I bought it and was owned by a girl bought new and I mean every thing was stock, belts, hoses, shocks everything and a lot of it new GM stuff. She took very good care of this car and I would think oil changes also. However I have changed a lot of parts with bolt ons and now putting more stress on parts and hoping to do some track days. So will it be run harder! Will the oil suffer more break down! I would have to say yes. We use to run super late model asphalt car and was on a every other race change interval and it would run out like water. We went to Mobil1(this was 7yrs back) and we would Change twice a season and the motor held up and looked like new when checked for new season like never before.
I can't change or even know what was done to my car before me but I can fill her with the best parts, oil, fuel, etc. and try and save a great running 15yr old car with 124k on the clock and if she breaks then I'll go from there but know I used the best.

[kingls1]

This thread takes me back to a non oil related test I read on helmets after I had a bad bike wreck and was in intensive care for 3 days with a head injury.
Test stated that helmets with the Snell rating was some times the reason for head injuries due to their strict testing the shells were being manufactured too stiff and that the less expensive D.O.T helmets were better because the softer testing standers the helmets would crack and give and would dissipate more energy thus not sending your brain slamming into your skull and causing injury/bleeding. Now I don't know if this would be true and somewhat makes sense but look at all 5 helmets in my garage and you will see the Snell rating on them all. Sure you can get the same use from a $99 helmet that you can from a $350 one and your engine will run on a $3 quart of oil just like it would on a $10 one but at what cost!

[35th-ANV-SS]

You guys are missing my point. If an oil has been used in a car for 15 years and has caused zero damage, it likely isn't going to. If damage has already been done, changing to a different oil isn't going to remedy that damage. I'm talking about the case where you are buying one of these cars for the first time and have no idea what's been done to it or used prior. Most 15 year old used cars are high mileage and oil would have already did damage if it was going to.

[98TransAmWs-6]

You guys are missing my point. If an oil has been used in a car for 15 years and has caused zero damage, it likely isn't going to. If damage has already been done, changing to a different oil isn't going to remedy that damage. I'm talking about the case where you are buying one of these cars for the first time and have no idea what's been done to it or used prior. Most 15 year old used cars are high mileage and oil would have already did damage if it was going to.

So your saying you should use subpar oil because you don't know what has been done with it since it can't do any further damage lol? I know that is not what you mean. While if there is damage in the physical variety it won't fix it but it won't make it worse either. It depends what type of damage we are talking about whether it can fix it or not as well. I personally regardless as to what I know about a vehicle will always use a high grade oil since it may increase life expectancy of the engine by protecting it from further damage it it were damaged.

The thing is you don't know whether an engine is damaged internally or not from subpar oils when buying a car unless it is severe but you still may not know then.

[35th-ANV-SS]

No, I understand what you're saying and I agree. I'm saying I think you would know whether an oil was doing its job or not after 15 years of use.

[35th-ANV-SS]

How long exactly will it take for bad oil to have adverse affects on the motor, if at all? Any guess? Lots of variables there.

I didn't use anything special on my 96 V6 Camaro and beat the shit out of that car. Sold it with 210,000 miles, so I put 185,000 hard miles on it. I was using Quaker State regular oil. Regular oil changes every 3K miles.

[pajeff02]

I am guessing that oil change interval and quality of filtration has more of an impact than the type of oil utilized. An engine that only saw 3,000 miles change intervals with cheap oil and filters may be in better shape than one that had the "good stuff", but went a year or three between changes. We have a neighbor that does not believe in oil changes -- his vehicles all run with the same oil and filter that they received from the factory until the day they expire. Go figure.

[98TransAmWs-6]

I am guessing that oil change interval and quality of filtration has more of an impact than the type of oil utilized. An engine that only saw 3,000 miles change intervals with cheap oil and filters may be in better shape than one that had the "good stuff", but went a year or three between changes. We have a neighbor that does not believe in oil changes -- his vehicles all run with the same oil and filter that they received from the factory until the day they expire. Go figure.

Depends on the oil, filtration used and what the condition of the oil was when changed. Obviously there are many more variables though. Some oils you can go a year without changing and they are still good, I wouldn't do it but Amsoil has some designed for that. Also an oil that doesn't protect adequately to begin with will cause much more premature engine wear than perhaps a much better than a high grade oil going longer intervals maybe not a year though. Regardless going long intervals is not a wise idea unless the oil is designed for that and the best choice for ones not designed for that is to use a high grade oil and filter for every 3k miles. Obviously, a racing grade oil like I use is not necessary for just a DD that is not heavily abused. But I would still suggest a high grade oil over the cheap stuff and the same with the filter.

Oil does not expire per say but it does stop protecting the engine adequately due to the additives no longer being present due to the oil deteroriating. Not sure how long that specifically takes since there are a lot of variables that would affect that.

[Firebirdjones]

I am guessing that oil change interval and quality of filtration has more of an impact than the type of oil utilized. An engine that only saw 3,000 miles change intervals with cheap oil and filters may be in better shape than one that had the "good stuff", but went a year or three between changes. We have a neighbor that does not believe in oil changes -- his vehicles all run with the same oil and filter that they received from the factory until the day they expire. Go figure.

Jeff, this is where oil annalys comes into play. The only way for any of us to know if the oil we are using, or the change intervals we decide on are working, is to send a sample to Blackstone and see what info comes back. Otherwise it's just our best guess.

Using an oil annalys could tell you how well the cheap oil is working and how long you can run it before it should be changed. The answers might just tell you that the cheap oil is doing just fine at 3,000 or even 4,000 mile intervals and there is no need to step up to a better oil unless you want to stretch your change intervals, that's one thing the better oil may allow you to do.

[Firebirdjones]

To Jon oil does not expire per say but it does stop protecting the engine adequately due to the additives no longer being present due to the oil deteroriating. Not sure how long that specifically takes sense there are a lot of variables that would affect that.

Oil annalys is the only way to know for sure. Each engine will be different regardless of oil because of how the engine may be used or the shape it's in, state of tune etc.... If you want to extend your oil changes it can be done safely with an oil annalys, once done it gives you an idea how long the oil and filter will do it's job. Then you'll get your money's worth out of your oil changes.

What I've done at 3,000 miles is send a sample in. They will tell you if it's time to change it based on many variables. If not, they'll give you an idea of how much longer to run before another annalys should be done. Might be 1,000 or 1,500 miles. So on and so forth.

In the end you may find your oil and filter can go 5,000 or 6,000 miles based on your driving habits, or possibly find out that it's time to change it at 3,000 miles.

[98TransAmWs-6]

Oh yeah I forgot about oil analysis for some reason. So yeah I am in agreement with FBJ the only way to tell what us exactly happening to your oil is to get it analyzed. Can't some oil analysis companies also tell you based on your results if you need to run a thicker or thinner oil as well?

[DADCRUISER]

I have used VALVOLINE 5-30W synthetic for more years then i can remember. just switched to max life 10-30w. I bought the car with 7k on it and now have 254k miles on it. This was until last may my deliver car for my publication delivery business. More times Than not I had so many publications in it, it looked like a low rider. Its been a real work horse. I also since 100k been using a Product called Restore. Car has never leaked oil. It doesnot burn oil neither did my Mercedes sl,sold at 185k, BMW 325e sold at 179k. I change oil aprox. every 3500-4000 miles. I damaged my oil pan last year and had to replace it and the rear main seal.

[kingls1]

I was thinking about our new Chevy Sonic we bought new in fall 2011. It has a change interval of get this 10,000 miles. I have not followed this factory recommendation and have change it between 3-5,000 miles. Said in the book it would monitor driving habits and adjust itself but that's not for me I keep track of mileage and change when due.

[35th-ANV-SS]

Yea, I've always went by the 3K mile rule myself as well. On occasion, I will let it ride out to 4 or 5K, and even then the oil monitoring system shows 40% or so left on my oil life.