Is it time to change oil viscosity?

[TURBO2]

I have a 1986 GN with around 108,000 miles on it. I'm using the factory suggested 10w-30 and have about 70 psi oil pressure when cold, but once it heats up the pressure drops to only about 17-18 psi. Should I switch to 10w-40 or 20w-50?

 

[dynoman]

Same as mine with 10w30 .... 70psi cold -- 18psi hot idle .

 

[THensley]

stay where your at all good

 

[deezdad]

What temp tstat? Stock, 180, 160 ?

 

[TURBO2]

What temp tstat? Stock, 180, 160 ?

160, but it goes beyond that since I put in the front mount intercooler. I have to put in some higher rate cooling fans to fix it.

 

[V6sleeper]

Many dont agree with this but i run Vr1 20/50 in NY summer and 10/40 in the fall/winter for 20 years , with only showing a 3 psi hot idle difference

A front mount will put you over 200 degrees on the streets without good dual fans

 

[deezdad]

Only my opinion but I wouldn't run a thicker oil with that cool of an operating temp especially with the fan upgrade.

 

[KC87]

The manual in my (87) says 5-30. Only used 10-40 from the start.
Back in the day Kenne Bell I would say was the big guru and always used 10-40 and recommended it.
And the 10-40 today is way better then 40 years ago
All those 6.2l engines GM has to recall use 0-20. One of the changes will be to have owners switch 0-40 or perhaps
5-40. Hoping to push it over the warranty.
I guess if you're buying new today you pick your poison and hope for the best.

 

[Ttype6]

I have a 1986 GN with around 108,000 miles on it. I'm using the factory suggested 10w-30 and have about 70 psi oil pressure when cold, but once it heats up the pressure drops to only about 17-18 psi. Should I switch to 10w-40 or 20w-50?

No, never. Also there's no reason to use a 10w30 when you can use a 5W30. 10w30 will be thicker when it's cold that's what the 10 stands for and you don't need it thicker when it's cold. There's nothing wrong with the oil pressure that you have but if you want to bring it up at hot idol, the thing to do would be to add a high volume oil pump. If you're not using Quaker State full synthetic 5W30 oil, you're not getting all the film strength that you might otherwise get by using this product. There's nothing out there that's better. It's the most important thing to look at when you choose a motor oil. Thicker oils do not have higher film strength and they're harder to flow through tight spaces and oils with zinc do not give them higher film strength. The highest film strength oils on the market have the lowest amount of zinc in them and Quaker State is the best but only full synthetic. If it says anything else on the label like ultra protection or super duper don't buy it and the only way to get a good deal on it is to buy it at Walmart.

 

[Turbo6inKY]

At the risk of devolving the thread into another oil holy war, there is no "best" oil. Which is best depends on your application and how you're using it.

But there are a lot of "good enough" oils, and almost everything in a 5w30 or 10w30 you can buy at a mainline store is good enough for a stock engine with regular (3000 miles or once a year, whichever you hit first) oil changes.

ZDDP is a high pressure additive that only kicks in once the film has failed. Most modern oils swap that out for molybdenum because excessive ZDDP tends to acidify the oil and it starts attacking the parts it's supposed to protect. If you've ever seen a camshaft with pitted lobes that didn't spend time under water, that damage was likely from excessive ZDDP in the oil combined with a too-long change interval.

Start tweaking the valvetrain or racing and things can change radically. I run Motul 300V in mine, because I get stuff really hot and it maintains film strength well past 300 degrees while most other store bought synthetics (including Quaker State's retail products) give up around 250-260. It's also $35 per two liter can, so I pay heavily for the feature.

And to reinforce for the OP, your oil pressures appear fine. Keep using the 10w30 in the summer and 5w30 in the winter like the sticker says. If you're really curious, get an oil sample analyzed. that'll tell you way more than the oil gauge can tell you.

High volume oil pumps just waste horsepower and create additional heat. Unless you've built an engine with enlarged clearances, it's not necessary. if you're looking at adding a HV kit to an old engine to compensate for wear, it's a band-aid. You're better off dropping the pan, inspecting everything, and rolling in a fresh set of bearings assuming the crank's OK.

 

[Ttype6]

At the risk of devolving the thread into another oil holy war, there is no "best" oil. Which is best depends on your application and how you're using it.

But there are a lot of "good enough" oils, and almost everything in a 5w30 or 10w30 you can buy at a mainline store is good enough for a stock engine with regular (3000 miles or once a year, whichever you hit first) oil changes.

ZDDP is a high pressure additive that only kicks in once the film has failed. Most modern oils swap that out for molybdenum because excessive ZDDP tends to acidify the oil and it starts attacking the parts it's supposed to protect. If you've ever seen a camshaft with pitted lobes that didn't spend time under water, that damage was likely from excessive ZDDP in the oil combined with a too-long change interval.

Start tweaking the valvetrain or racing and things can change radically. I run Motul 300V in mine, because I get stuff really hot and it maintains film strength well past 300 degrees while most other store bought synthetics (including Quaker State's retail products) give up around 250-260. It's also $35 per two liter can, so I pay heavily for the feature.

And to reinforce for the OP, your oil pressures appear fine. Keep using the 10w30 in the summer and 5w30 in the winter like the sticker says. If you're really curious, get an oil sample analyzed. that'll tell you way more than the oil gauge can tell you.

High volume oil pumps just waste horsepower and create additional heat. Unless you've built an engine with enlarged clearances, it's not necessary. if you're looking at adding a HV kit to an old engine to compensate for wear, it's a band-aid. You're better off dropping the pan, inspecting everything, and rolling in a fresh set of bearings assuming the crank's OK.

Only one thing you said is true and that is that there are many oils that are good enough but they all cost more than Quaker State full synthetic 5W30 if you buy it at Walmart and none of them have the film strength that Quaker State does.

 

[turbocamino1]

At the risk of devolving the thread into another oil holy war, there is no "best" oil. Which is best depends on your application and how you're using it.

But there are a lot of "good enough" oils, and almost everything in a 5w30 or 10w30 you can buy at a mainline store is good enough for a stock engine with regular (3000 miles or once a year, whichever you hit first) oil changes.

ZDDP is a high pressure additive that only kicks in once the film has failed. Most modern oils swap that out for molybdenum because excessive ZDDP tends to acidify the oil and it starts attacking the parts it's supposed to protect. If you've ever seen a camshaft with pitted lobes that didn't spend time under water, that damage was likely from excessive ZDDP in the oil combined with a too-long change interval.

Start tweaking the valvetrain or racing and things can change radically. I run Motul 300V in mine, because I get stuff really hot and it maintains film strength well past 300 degrees while most other store bought synthetics (including Quaker State's retail products) give up around 250-260. It's also $35 per two liter can, so I pay heavily for the feature.

And to reinforce for the OP, your oil pressures appear fine. Keep using the 10w30 in the summer and 5w30 in the winter like the sticker says. If you're really curious, get an oil sample analyzed. that'll tell you way more than the oil gauge can tell you.

High volume oil pumps just waste horsepower and create additional heat. Unless you've built an engine with enlarged clearances, it's not necessary. if you're looking at adding a HV kit to an old engine to compensate for wear, it's a band-aid. You're better off dropping the pan, inspecting everything, and rolling in a fresh set of bearings assuming the crank's OK.

I’ve had mine over 280 a couple times. This was at a hill climb contest close proximity to Death Valley, and there are times when we’re the hottest place on earth. Car runs like shit .. can't imagine how you would get to 300* unless hot lapping a huge engine? Take an average of film strength, sheer rate and viscosity breakdown tests and QS full synth wins the psi test..nothing being more important than film strength. All cover by Rat 540 oil tests. However ,we all know, it can develop oil leaks..been there done that so may not be the best go to for our Buick engines?

 

[THensley]

Some of the best pissing matches are oil topics.
If I need something from Walmart that will cover my ASS ill buy underwear not oil.

 

[TexasT]

I love these oil threads! I know what I use, Many others know what they use and then there are the "what do I use" guys. It is oil and an engine definitely NEEDS it to keep spinning. Next up! oil filters! hahaha