Consumption with thin vs. start up wear with thick

[byez]

So whats worse, using a thin oil and having consumption or using a heavy oil and more start up wear?

Is oil consumption bad for the engine or just bad for your wallet?

With all being said, I am in a relatively cold climate compared to most of the US and would probably never use a 40 weight. Manual specs 5w30, considering trying out 0w20 or 5w30.

 

[Titan]

I guess you are looking at different HTHS values, rather than just viscosity. IOW, I do not hold your view that "thin" oil is necessarily consumed at a higher rate than a "heavy" oil. In my engines, there is no significant consumption of "thin" oil...but, I would not be completely surprised if certain "heavy" oils would result in a higher rate of consumption.

 

[Pablo]

Originally Posted By: Titan
...... I do not hold your view that "thin" oil is necessarily consumed at a higher rate than a "heavy" oil. In my engines, there is no significant consumption of "thin" oil...but, I would not be completely surprised if certain "heavy" oils would result in a higher rate of consumption.


You don't know how correct you are. My Volvo consumes essentially zero 0W-30, XW-40 it drinks.

 

[d00df00d]

If I absolutely had to choose, I'd much rather have better wear protection than slower consumption.

 

[Delphi]

Originally Posted By: Pablo
You don't know how correct you are. My Volvo consumes essentially zero 0W-30, XW-40 it drinks.

Do you have any explanation why is it happening?

 

[Pablo]

Originally Posted By: Delphi
Originally Posted By: Pablo
You don't know how correct you are. My Volvo consumes essentially zero 0W-30, XW-40 it drinks.

Do you have any explanation why is it happening?


I cannot say for certain, but I think it's:

1) perhaps the thicker film strength actually leaves more oil on the cylinder walls and is burned in combustion.

2) the composition of the oil itself is more easily broken down because the 40 has more VII's.

3) I'm on crack.

 

[Oilgal]

 

[BennyL]

Pablo, you gotta kick that crack habit

What does the volvo manual spec?

 

[Pablo]

I believe the manual ranges from 5w30 to 15w40 for the 1996 850. (I'll check when I get home)

Per the guidebook:

Quote:
Engine Oil
Grade 1......API*
SAE 10W-40 XL Synthetic Motor Oil
SAE 10W-40 Synthetic High Performance Motor Oil
Synthetic 5W-40 European Engine Oil
-4 to 104°F......10W-30
Above 0°F......15W-40
Below 68°F......5w30
Below 104°F......5W-40

 

[Oilgal]

Originally Posted By: Pablo


1) perhaps the thicker film strength actually leaves more oil on the cylinder walls and is burned in combustion.



Last year, I ran an OCI of 5w30 Redline, in my Mistsu 3.0. Oil consumption went way up, and I thought the same thing at the time. My ring packs however, though I didn't know it then, were badly coked up. I wonder what would happen, a few OCIs after, I finish this second ARX treatment?

 

[BennyL]

Pablo, what oil do you use in it now?

 

[Pablo]

SSO 0w30 for the last 6K or so and hasn't used a drop.

It has almost 120,000 miles on it.

 

[edhackett]

I think it has a lot to do with the oil composition. I ran Mobil 1 10w30 (pre Tri-Syn formula) in my 1995 Subaru and it always used 1/2 quart per 5K OCI no matter how it was run. The first and second OCI on the 10w30 Tri-Syn formula resulted in 2 qt per 5K consumption. At that point I wrote off Mobil 1 permanently and went to Delo 400 15w40. The oil consumption immediately returned to 1/2 qt per 5k and was still at that rate when I sold the car at 200K.

Ed

 

[Max_Wander]

Originally Posted By: edhackett
...[M1] formula resulted in 2 qt per 5K consumption. At that point I wrote off Mobil 1 permanently


Your observation of Mobil 1 burning off is not unique, however you got a step ahead of most people in recognizing the problem, and ceasing usage. I've known people who have raced with Mobil 1 in low mileage engines, only to have the oil burn off, and the pump suck air.