HTHS questions

[RF Overlord]

Originally Posted By: steve20
I thought the 10-30 started life as a 30, not a 10--you sure about that?
Yes. All multigrade oils start life as a 5 or 10. The added viscosity index improvers make them behave like a 30 when hot.

 

[dailydriver]

Originally Posted By: CATERHAM
BTW, the reason that our good freind A.E. Haas can run the RLI 0W-20 in his wife's Lambo is because it has a HTHSV equal or greater than 2.95cP.


Also, because it is probably ever driven at 4/10ths of it's potential, MAX, and even at that level for only very brief periods of time.
Even if it would shear (or the VIIs shear down), it does not get used hard enough for this to happen, save for maybe some very slight fuel dilution.

 

[dparm]

Oil temperatures and overall pressure in the bearings is still enough to pummel that oil.

 

[Tempest]

Originally Posted By: RF Overlord
Originally Posted By: steve20
I thought the 10-30 started life as a 30, not a 10--you sure about that?
Yes. All multigrade oils start life as a 5 or 10. The added viscosity index improvers make them behave like a 30 when hot.


This little bit of in accurate information from Haas' misinformation piece is killing me.

Finished oils are a mix of different base oil to get the desired end results. Some maybe 10 grade, and others maybe different.

 

[edhackett]

Yes, as Tempest mentions, it's much more complicated than that. Most multi-grades will be a base stock, more than likely a mix of two or more single viscosity base stocks. VI improvers are used to stretch the high end and pour point depressants are used to stretch the low end. The amount and type of each will depend on the desired grade and viscosity characteristics of the end product. The additive package will vary to achieve the desired goal based on the viscosity and viscosity index of the base stocks used.

That's still just a basic explanation of what's involved with formulating a multi-viscosity oil.

Ed

 

[iunderpressure]

I ordered the red line 0w20, so we'll see.

 

[Geonerd]

Looking at http://new.volvocars.com/ownersdocs/1996/1996_850/96850_901.htm it seems Volvo is leaning toward the thicker end of the 30w spectrum. RL's 0w-20 is no doubt a great oil, but it's a hair thin for my comfort level. A blown engine will place a lot of load on the bearings at at lower RPM, pushing you further to the left on the Striebeck curve, a place you don't want to go. Will this cause your engine to explode? Probably not, but I really don't know - I'm not a Volvo engineer! (And neither is anyone else on this board.) In the absence of real information, I'd rather err on the side of caution.

Honestly, I think you're barking up the wrong tree. Using thinner oil may save you half an MPG (if that), but small changes to your driving habits will save you many times more. Slow down on the freeway. Anticipate traffic and lights in town. Have you checked your tire pressure lately? Consider running your tires a few PSI over the factory value - this along will do more than any oil change.

 

[CATERHAM]

Originally Posted By: Geonerd
Looking at http://new.volvocars.com/ownersdocs/1996/1996_850/96850_901.htm it seems Volvo is leaning toward the thicker end of the 30w spectrum. RL's 0w-20 is no doubt a great oil, but it's a hair thin for my comfort level.

10W-30 is spec'd for temp's up to 104F.
M1 10W-30 has a HTHSV of 3.0cP.
RL 0W-20 has a HTHSV of 3.0cP, plus it's POE/PAO based with zero VIIs.
Seems like an excellent choice to me and anything but too light.

 

[Geonerd]

I'm seeing RL's 0w-20 HTHS at 2.7 Not a huge deal, but is IS lower than what Volvo have in mind. Yes, it's got gobs of additives and won't thin with use, but it is still a hair 'thin.'

The fact that Volvo show different temp ranges for the 5 and 10W-30 oils suggest that they are worried about oils with more VIs (the 5w-30) shearing below grade. Since Xw-30 is nominally >= 2.9 it seems prudent, IMO, to be sure your oil isn't any thinner.

 

[dparm]

That's the old debate about shear-proof oils. Do you safely go for a thin one knowing that a regular oil would've sheared to that level? Or do you stick with the "correct" viscosity from the start?

 

[CATERHAM]

First don't believe every thing you read.
While the RL 0W-20 is RL's lightest street oil it is anything but a true 20wt oil. It is a 30wt oil in everything but name.

Originally Posted By: CATERHAM


Two reasons why I believe it is 3.0cP instead of the claimed 2.7cP.
The oil has been tested by a very reputable lab' and it came in at with a HTHSV of 3.0. Since I didn't pay for the info I can't reveil the name of the lab'.
Secondly, if you read the product description on an actual bottle of the RL 0W-20 it says the following:
"Red Line 0W-20 provides more bearing viscosity than most petroleum 5W30s......Formulated to suit the requirement for ACEA A3, and B3/B4"
Bearing viscosity is sort of a layman's reference to HTHSV.

 

[iunderpressure]

The rl 0w20 was put in the volvo yesterday.

 

[zoli]

Originally Posted By: iunderpressure
The rl 0w20 was put in the volvo yesterday.

I'm very curious about top up oil amounts - seems to me extremely thin for this '96 turbocharged Swedish car...

 

[CATERHAM]

Originally Posted By: zoli
Originally Posted By: iunderpressure

I'm very curious about top up oil amounts - seems to me extremely thin for this '96 turbocharged Swedish car...

What's thin about a HTHSV 3.0cP, VII free oil?
It meets Volvo's viscosity requirements.