How does Heat NOT affect Oil selection? 0W-30 vs ?

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halseywales

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Im confused here. I just passedup some GC 0W-30 and went with 20W-50 (full synthetic 20W-50, for flow) in my car. What would have happened if id have chose 0W-30?

This is the 1994 LHS.

And im also sure my engine DOESNT like 5W-20.. anything could make it blow up! No idea how hot it runs, but its older and i think it likes its thick Oil. I drive it a lot, too.

Did i make the right choice?
 
Originally Posted By: justinf89
Yea id go back and get the gc. 50w is way too thick.


All manufacturer recommendations aside.. why?

Isnt 20W-50 better?
 
I'm sure their engine engineers are more qualified than us. I'd go with what is recommended.
 
Originally Posted By: halseywales
All manufacturer recommendations aside.. why?

Isnt 20W-50 better?

You only want your oil to be as thick as necessary. Thicker doesn't necessarily mean better protection... in fact, it means the oil will not flow as easily, especially during cold startups. That means increased wear.

Each engine has an operating oil pressure specification, though you may need to buy a shop manual to know what it is. Ideally, every vehicle would have an accurate oil pressure gauge so you could check against the standard... and pick the thinnest oil that gives an oil pressure that meets the standard.

Since the vast majority of cars don't have OP gauges, the best thing to do is stick with the recommendation in the owners manual, with the possible exception of going up one grade in extremely hot locations, or down one in extremely cold locations.
 
Originally Posted By: halseywales
Originally Posted By: justinf89
Yea id go back and get the gc. 50w is way too thick.


All manufacturer recommendations aside.. why?

Isnt 20W-50 better?

No offence, but what part of "way too thick" didn't you understand?

For starters, your oil pump will be in by-pass mode most of the time further reducing the all ready reduced oil flow. During cold starts you're at serious risk of oil cavitation if you rev the engine too high.
 
Define better?

a thick [censored] viscosity oil is not better,maybe in certain applications it's more desired but better? no.
 
Well...let's remember that the specified viscosity for the new Mustang Boss 5.0 is 5W-50. So there must be some validity to more protection at higer viscosities. This, after Ford has recommended 5w-20 for much of their product lineup for years.
 
.....and your oil filter was specd. for a particular oil weight. When the oil's cold, 90 percent of that 20/50 is likely bypassing the filter and even when hot, a good portion is bypassing.
 
Originally Posted By: halseywales
What would have happened if id have chose 0W-30?

Your engine would have been better protected at cold startup because 0w-30 doesn't thicken up as much as 20w-XX when cold.

On top of that, Xw-30 flows better than Xw-50 at operating temp. All you're doing is robbing your engine of power and not really getting any benefit of thicker oil if your engine doesn't require it.
 
Well, it is a 17 year old engine...
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But I've been running oil that is "too thin" in our Chrysler since 5000 miles without any issues.

A significant portion most automotive forums will tell you that the Neon SRT/4-PT Cruiser GT engine is a "piece of [bad word]" and anything can make it "blow-up". Certainly running a 5W30 when a 10W30 is spec'd for temps over 100° meets their specious criteria.

I just drove it. Still pulls hard from 2000-3000rpm and real hard from 3000 to 6000. No knocks no rattling valvetrain.

So, what's the most likely scenario running 0W30 in your LHS over 20W50? a smidge more fuel economy and a little better cold engine start-up oil circulation. The 20W50 could be a lot more detrimental.

Besides, how hot is it there really? I went to college up north. The Great Lakes area gets humid but not really hot....certainly not 110° daytime high and 95° overnight low for a month or two straight. Those are the conditions my tightly packed turbo Chrysler endures on 5W30
 
Use viscosity as a bandaid for excessive oil temps or heat produced by higher horsepower engines.

Use viscosity as a bandaid to sometimes help reduce oil consumption.

So, what are the issues that you're trying to band-aid? Did you bolt on twin turbos or a supercharger or something? Are you burning a quart or two a day?

If not stick with the 30wt oil. If you want a little more visc, then the Castrol Syntec 0w30 and Mobil1 0w40 are excellent choices. 5w40 is another easy choice. Mobil1 has a great 10w40 highmileage oil. Castrol still sells a 5w50. I wouldn't jump to 20w50 in a northern climate.
 
Originally Posted By: beechcraftted
Well...let's remember that the specified viscosity for the new Mustang Boss 5.0 is 5W-50.

Correct, as stated with certain applications. but the OP is specking in general.
 
Originally Posted By: halseywales
All manufacturer recommendations aside.. why?

Isnt 20W-50 better?


Grease is a lubricant and even thicker yet. Can you think of reasons why you wouldn't want to use something as thick as grease in your engine?

Now apply that same thinking to something like 20W-50. In some applications and circumstances it's appropriate, but probably not yours.
 
Worse than the 50wt is the 20W. Why would anyone buy a 20W50 these days, and in Michigan of all places. Even if someone incorrectly thought their standard passenger car required a 50wt oil for whatever reason, there are 5W50's available.
 
Originally Posted By: unDummy
Use viscosity as a bandaid for excessive oil temps or heat produced by higher horsepower engines.

Use viscosity as a bandaid to sometimes help reduce oil consumption.

So, what are the issues that you're trying to band-aid? Did you bolt on twin turbos or a supercharger or something? Are you burning a quart or two a day?

If not stick with the 30wt oil. If you want a little more visc, then the Castrol Syntec 0w30 and Mobil1 0w40 are excellent choices. 5w40 is another easy choice. Mobil1 has a great 10w40 highmileage oil. Castrol still sells a 5w50. I wouldn't jump to 20w50 in a northern climate.



concur - did you happen to look at Dr. Haas' articles? See chapter 5: http://www.bobistheoilguy.com/cms/index.php?option=com_content&view=article&id=79 But I recommend that you read all of the oil 101...thicker ain't always better....
 
Originally Posted By: daman
Originally Posted By: beechcraftted
Well...let's remember that the specified viscosity for the new Mustang Boss 5.0 is 5W-50.

Correct, as stated with certain applications. but the OP is specking in general.

It may say 50wt on the bottle, but the Motorcraft 5W-50 shears to a light 40wt if not a 30wt almost immediately in service. I guess Motorcraft can't formulate a shear resistant 5W-40 oil.

Whenever a manufacturer spec's an oil heavier than a 40wt it is for intended possible track use.
 
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