You thin oil guys are a baddd influence :^)

[ericthepig]

That chart reaffirms my own "freezer test" findings. 10w oils under -10degF are molasses. If there's a chance your winter temps could dip there, I wouldn't have it in the crank case.

Meanwhile, what's up with that asterix note cautioning against 5w20 for extended high speed driving ?

 

[sunfire]

Originally Posted By: aquariuscsm
I took some much needed vacation days (heading up to Nashville for the Nascar race). So I`m bored at home and started thinking how bad I wanted to tinker with my car! Sooooooo,I had some Valvoline 10W40 dino sitting around and well,out goes the 20W50 and in goes the 10W40. How do you say night and day diference????? Feels like a different car! Engine is so smooooooth and quiet! It felt really weird when I broke the rear tires loose accelerating in 3rd gear! Did the 20W50 really rob my car of that much power? If I`m really brave,I may drop down to their 10W30 next oci. Don`t know if I`m brave enough to try a 5W30 though,since the factory fsm says not to,although there`s a guy on one of the Z32 forums that uses Pennzoil dino 5W30 in his twin turbo Z and swears by it.


You are going to the Dark Side!

Be a man and use a synthetic 5W-20 like PP.

 

[MrWideTires]

This is what I would do if I was you to protect that prescious car:

1. Buy two 5gt jugs of 5W30 SUPERTECH synthetic, they are only $17 each. Run them for a really short OCI because it's going to clean out any [censored] the heavy 20W50 left behind..
2. Then buy either Mobil-1 0W40, or GC 0W30 (GC is a more like a 0W40) and drive your car happily with however long OCIs you wanna go. Your car is going to run so much better with those oils and once all the [censored] is cleaned out of it.

 

[BuickGN]

Originally Posted By: MrWideTires
This is what I would do if I was you to protect that prescious car:

1. Buy two 5gt jugs of 5W30 SUPERTECH synthetic, they are only $17 each. Run them for a really short OCI because it's going to clean out any [censored] the heavy 20W50 left behind..
2. Then buy either Mobil-1 0W40, or GC 0W30 (GC is a more like a 0W40) and drive your car happily with however long OCIs you wanna go. Your car is going to run so much better with those oils and once all the [censored] is cleaned out of it.


Yes, because 20w-50 leaves all kinds of junk behind...

 

[Drivebelt]

That chart that recommends not using 5W-30 in below 59F weather is outdated, and really only applies to the old Group I based 5W-30's that were in use in the 1980 - 1990's.

The current Group II (+) based conventional SM/GF-4 5W-30's are in a completely different ballpark as far as performance goes. They use almost synthetic quality base oils. You can use them towing a 6,000lb trailer in 110F weather, and they hold up just fine.

 

[MrWideTires]

Originally Posted By: BuickGN
Originally Posted By: MrWideTires
This is what I would do if I was you to protect that prescious car:

1. Buy two 5gt jugs of 5W30 SUPERTECH synthetic, they are only $17 each. Run them for a really short OCI because it's going to clean out any [censored] the heavy 20W50 left behind..
2. Then buy either Mobil-1 0W40, or GC 0W30 (GC is a more like a 0W40) and drive your car happily with however long OCIs you wanna go. Your car is going to run so much better with those oils and once all the [censored] is cleaned out of it.


Yes, because 20w-50 leaves all kinds of junk behind...

It did in my dad's car, I made him change to 0w30 in a 200,000 mile car... it couldn't be running better now, what seemed like a car that was apparently dying of age, it's now a car that can take some abuse and comes back for more.

 

[BuickGN]

Originally Posted By: MrWideTires
Originally Posted By: BuickGN
Originally Posted By: MrWideTires
This is what I would do if I was you to protect that prescious car:

1. Buy two 5gt jugs of 5W30 SUPERTECH synthetic, they are only $17 each. Run them for a really short OCI because it's going to clean out any [censored] the heavy 20W50 left behind..
2. Then buy either Mobil-1 0W40, or GC 0W30 (GC is a more like a 0W40) and drive your car happily with however long OCIs you wanna go. Your car is going to run so much better with those oils and once all the [censored] is cleaned out of it.


Yes, because 20w-50 leaves all kinds of junk behind...

It did in my dad's car, I made him change to 0w30 in a 200,000 mile car... it couldn't be running better now, what seemed like a car that was apparently dying of age, it's now a car that can take some abuse and comes back for more.


I'm not trying to sound harsh, my other post came across that way after reading it.

It's not the weight of the oil but the quality. I would bet money that a high quality synthetic 50wt would keep an engine cleaner than a dino 30wt.

 

[Calvin]

" Did the 20W50 really rob my car of that much power ? "

Many years ago I made a mistake and bought a case of Kendall SAE 40WT when I thought I was buying SAE 30WT......... I then changed my oil on my solid lifter 427 Chevy...... I fired up the engine and looked at the tach and thought " What the heck "
all I did what change the oil and filter and my idle speed dropped 200 RPM... and the crisp throttle response suddenly just felt a bit sluggish.It was only after that , that I noticed I messed up and bought the wrong oil.After changing back to 30WT my idle speed raised up the lost 200 RPM right back to where it was before.

The heavy oil put enough strain on my Big Block that it caused idle speed to drop that much........ cant help but wonder what a difference it might have made on a small engine.

 

[vxcalais]

Originally Posted By: Drivebelt
That chart that recommends not using 5W-30 in below 59F weather is outdated, and really only applies to the old Group I based 5W-30's that were in use in the 1980 - 1990's.

The current Group II (+) based conventional SM/GF-4 5W-30's are in a completely different ballpark as far as performance goes. They use almost synthetic quality base oils. You can use them towing a 6,000lb trailer in 110F weather, and they hold up just fine.


What happened to 'Follow what the manufacturer recommends' ? Does it only suit when they recommend a 5w30 and someone uses slightly thicker ? When they recommend thicker is it out of date ? 20w50 oil is not poison...... there's Group 3 25w60 oils i know off that can offer better 'bearing' and all round protection than many over the counters here where i am. Quality oil is what counts as what the BuickGN mentioned. Yes it isnt the best for a winter startup, and quick pullout of the driveway, but the proof is in the pudding. All those cars you see out there from 20 years ago, what did they run on ???

 

[BuickGN]

Originally Posted By: vxcalais
Originally Posted By: Drivebelt
That chart that recommends not using 5W-30 in below 59F weather is outdated, and really only applies to the old Group I based 5W-30's that were in use in the 1980 - 1990's.

The current Group II (+) based conventional SM/GF-4 5W-30's are in a completely different ballpark as far as performance goes. They use almost synthetic quality base oils. You can use them towing a 6,000lb trailer in 110F weather, and they hold up just fine.


What happened to 'Follow what the manufacturer recommends' ? Does it only suit when they recommend a 5w30 and someone uses slightly thicker ? When they recommend thicker is it out of date ? 20w50 oil is not poison......


Agreed.

Always follow the manual. The manufacturer knows what's best.......... unless it recommends a heavy oil then disregard the manual lol.

The way I look at it is imagine the oil adds an impossible 10hp. 10hp is not really perceptible to the butt dyno in a 3,500lb car.

 

[vxcalais]

The ecotec v6 3.8 litre first recommended 20w50. Few years later in newer models same engine, recommended 10w30. All the oil stores and Holden service centres retracted it somewhat. It was clear this was an emmisions requirement and marketing MPG. Even in the book it says 'for best fuel economy'.....then is says use a 15w40 in snow areas and 20w50 oils if 10w30 not available. Same engine, diff spec, they would not even use the stuff themselves. Yes some engines may be designed specific for very thin oils, in cold conditions.... but thick is not necessarily bad....any woman would certainly agree....

 

[Johnny]

Originally Posted By: aquariuscsm
I took some much needed vacation days (heading up to Nashville for the Nascar race). So I`m bored at home and started thinking how bad I wanted to tinker with my car! Sooooooo,I had some Valvoline 10W40 dino sitting around and well,out goes the 20W50 and in goes the 10W40. How do you say night and day diference????? Feels like a different car! Engine is so smooooooth and quiet! It felt really weird when I broke the rear tires loose accelerating in 3rd gear! Did the 20W50 really rob my car of that much power? If I`m really brave,I may drop down to their 10W30 next oci. Don`t know if I`m brave enough to try a 5W30 though,since the factory fsm says not to,although there`s a guy on one of the Z32 forums that uses Pennzoil dino 5W30 in his twin turbo Z and swears by it.


It's time to go to school. Now, write on the chalk board 100 times, Pennzoil Platinum 10W-30. When your through, go change your oil. You will be pleasantly surprised.

 

[SpitfireS]

Almost everybody is talking about the viscosity.
What about the API rating that is/was/should be recommended in the 1990-1996 manual?

I mean, a modern API-SM 5W-30 will be better than a 1990 5W-30, or 10W-30, right?

Manuals are the first place to look for oil recommendations.
But don't forget to look at the date/age of the manual and adjust oil selection accordingly.
IMO!

 

[Art_Vandelay]

Originally Posted By: aquariuscsm


Here`s a page from the 1990-1996 Z32 fsm:

This chart suggests that almost any weight oil is acceptable as long as it is temperature appropriate.

Use German Castrol 0W-30. It replaces everything on that page. A lot of knowledgeable people here consider it one of the best oils in the world. Especially when price is considered. It's more robust than any 5W/10W-30. It's a heavier 30 weight with a pour point down to -54C. It's a perfect match for your car.

Almost every thread written about GC states that it is practically a 40 weight oil. Given your concern in trying a 10W-30, this oil may as well have been custom engineered just for you. Read all about it on here.

 

[wannafbody]

5W30 isn't recommended for use above 59 degrees F? That doesn't make sense to me

 

[ADFD1]

That chart leaves a lot to the imagination.

AD

 

[Drew99GT]

The chart is for a 1996 vehicle. Many oil viscosity charts for cars of that time frame had different viscosities for different temperature ranges. This was back in the day when VII weren't nearly the quality they are now, and bsae oils weren't nearly as refined. NOACKS are probably 50% better for modern passenger car oils. Hence, a 5w-30 is probably just fine because it won't break down and vaporize from heat during high speed diving.

 

[ikeepmychevytoo]

My chart form 1984 (with API SF specification) is similar. Only 5w 30 is acceptable up to 100°F. 20W-20 is similarly suitable for hotter weather.

While 10W-30 is acceptable the whole hot side and 5W-30 is only up to 59°F looks like what they are suspecting about is the stability.

 

[BuickGN]

Originally Posted By: Art_Vandelay
Originally Posted By: aquariuscsm


Here`s a page from the 1990-1996 Z32 fsm:

This chart suggests that almost any weight oil is acceptable as long as it is temperature appropriate.

Use German Castrol 0W-30. It replaces everything on that page. A lot of knowledgeable people here consider it one of the best oils in the world. Especially when price is considered. It's more robust than any 5W/10W-30. It's a heavier 30 weight with a pour point down to -54C. It's a perfect match for your car.

Almost every thread written about GC states that it is practically a 40 weight oil. Given your concern in trying a 10W-30, this oil may as well have been custom engineered just for you. Read all about it on here.


GC is more robust than any 10w-30??? Not so sure about that.

 

[Drivebelt]

Originally Posted By: BuickGN
Originally Posted By: vxcalais
Originally Posted By: Drivebelt
That chart that recommends not using 5W-30 in below 59F weather is outdated, and really only applies to the old Group I based 5W-30's that were in use in the 1980 - 1990's.


What happened to 'Follow what the manufacturer recommends' ? Does it only suit when they recommend a 5w30 and someone uses slightly thicker ? When they recommend thicker is it out of date ? 20w50 oil is not poison......


Agreed.

Always follow the manual. The manufacturer knows what's best.......... unless it recommends a heavy oil then disregard the manual lol.


Obviously my post should have read "not using 5W-30 above 59F" ..oops.

If you just want to blindly follow the chart then that's fine. But then that is just not doing any analysis or thinking about the recommendations on the chart.

Notice that 10W-30 is recommended in all-weather conditions, even above 100F -- the same range as the heavier viscosity oils. So a 30 weight oil is OK above 59F if it is a 10W-30, but a 30 weight is not recommended if it is a 5W-30? Now why would that be -- they're both 30 weight oils. What could possibly be wrong with a 5W-30 compared to a 10W-30?

How about that the old 5W-30's when using lower VI Group I base oils, loaded up with VII's, just didn't hold up that well in hot weather. It was the same problem with the GI based 10W-40's back then too. They were poor oils because they had to be loaded up with VII's to make the viscosity spread. Factor in that GI base oils back then weren't very good base oils to begin with, and you have concerns about a 5W-30 or 10W-40 GI based oil holding up in hot conditions.

As I already pointed out, with the Group II+ base oils being used in 5W-20, 5W-30's these days, this is not an issue any more. Look at Ford and their 5W-20 recommendations for the F-150. Even if towing a 7,000lb trailer in 115F weather, Ford says the current 5W-20's are good enough to handle it.

The current GII based SM/GF-4 oils are in a whole different league performance wise compared to the previous GI oils they replaced, so using a 5W-30 in place of a 10W-30 these days it not and issue anymore.