Wrenchin... Adventures under the hood... Put em here.

[basinbeater]

Yeah don't. Ive gone in there, and you get confused because they kind of go around in circles. Oil selection is pretty simple I think.
Use synthetic whenever possible. It is more durable, and longer lasting.
Use the viscosity that is specified in the owners manual. Sometimes it is printed on the filler cap.
The engineers who designed the car know what it needs.

sent from Utah.

[bodywhomper]

Thanks. Appreciate the multiple and consistent recommendations.

Sent from my SPH-L710 using TGR Forums mobile app

[basinbeater]

I need an exhaust put on my little convertible. Made me think of this...
https://youtu.be/zUXow3d3-b0

sent from Utah.

[LHutz Esq]

Technically not - under the hood exactly.

But my 94’xr250l was blowing a bit of blue, stopping like a bag of mush, and stumbling at full throttle.

So yesterday she got blown a part.


New pads all round, new bearings in the front, new jets and the top end is off to the machine shop for some love.

Ordered a new coil so hopefully that and the new jets will fix up the stumble.

Now we wait for parts and time.

[MakersTeleMark]

You have your own lift!

[Ted Striker]

I was hoping to not dive into another forum (bob the oil guy).

Yeah don't. Ive gone in there, and you get confused because they kind of go around in circles.

Yeah, I'm not registered there or anything, but there is good info that can be uncovered with a search. The oil filter threads in particular show that there is a wide range of quality-to-crap.

some oil 101:
The first number (with the W) is the viscosity (resistance to flow, aka weight) at 0 degrees F, and the second number is the viscosity at 212 degrees F. So the idea there is to choose the first number for the coldest starting temperature expected, and the second number for the condition of the engine i.e. factory spec or wear (confirmed low oil pressure).

In a conventional (mineral) multi-weight oil the first number is the actual weight of the base oil, and the weight of second number is achieved by adding polymers (known as viscosity improvers) that "thicken" the oil as its temperature increases. In other words, 5W-30 is 5 weight oil that acts like 30 weight at operating temperature. The reason they do it this way is that the base oil from the refinery has a fairly limited temp range at any given weight.

Over time those VIs break down, and you're left with something closer to the first number than the second. And the oils with the greatest difference between those numbers obviously have the most VIs, so all else being equal, a 10W-40 will break down "farther" than a 10W-30. And that's what the old change intervals were based on.

Synthetic is still derived from crude oil, but processed with more hydrocracking (refining). This produces a base that flows better at low temperatures yet doesn't break down at higher temperatures. So when they say 0W-20 they're really describing the range of the base, not VIs. And that's why the change intervals are longer.

[basinbeater]

It's really easy. Every car specifies what oil should be used in the owners manual. To continue using the 100 series Land cruiser example, it spells it out in the owners manual.

The below is pulled straight from the Land cruiser owners manual. Use 5w30. Use synthetic, brand doesn't really matter.

sent from Utah.

[Ted Striker]

Agree.

[Todd Zander]

This is what I have always followed. My Saab guy whom I truly trust switch me off synthetic in a higher mileage 9-5

Sent from my Pixel 2 using TGR Forums mobile app

Disagree.

[Skidog]

Disagree.

Yeah I'm so not a car guy. At least fixing em, but I trusted this guy..he knew Saabs and she's still running strong at over 160k. 2008.

Sent from my Pixel 2 using TGR Forums mobile app

[basinbeater]

Yeah disagree. I would use synthetic, and if it developed leaks because of the switch to synthetic, fix the leaks.

sent from Utah.

[gravitylover]

My car is supposed to use 0W-20 here in the US but in other countries it's 0W-30 and in a few warm spots it 5W-30 and in the middle east it's 10W-30. Here in the US and in Euroland it's the lower viscosities mostly due to fuel economy regs. It's very common for people to run the 5-30 in the summer or for track use, that 0-20 is like water.

[KyleLanTheman]

The only time conventional should be used instead of synthetic is in a wankel, unless the omp is blocked off and you're running 2stroke in the gas.

^the only hesitation I'd have with running a thicker weight than listed in a 0w20 car is how high pressure may get during cold starts. Today's fuel efficient engines are built very, very tight.

Bob is the oil guy is great, here's a quick summary:
Brand doesn't matter, any quality synthetic will outlast filter capacity. Don't use fram filters.
That's about all you need to know

[Skidog]

Yeah disagree. I would use synthetic, and if it developed leaks because of the switch to synthetic, fix the leaks.

sent from Utah.

For the record the Saab hasn't dripped a drop of oil.

Sent from my Pixel 2 using TGR Forums mobile app

[The Tortoise]

:
Brand doesn't matter, any quality synthetic will outlast filter capacity. Don't use fram filters.
That's about all you need to know

Except the Fram Ultra filter is well regarded.

[basinbeater]

For the record the Saab hasn't dripped a drop of oil.

Sent from my Pixel 2 using TGR Forums mobile app

Give it time...

sent from Utah.

[Skidog]

Give it time...

sent from Utah.

How much 160k+ on the clock

Sent from my Pixel 2 using TGR Forums mobile app

[bagtagley]

I wouldn't go out of my way to swtich to synthetic in an older car that's been run on dyno. "Fix the leaks" is fine if you have the space, tools, time, and desire but is a pain in the ass and what's the benefit outside extended OCIs or maybe escaping your wife and kids (totally valid)? The reason for the talking in circles on BITOG is because there's very little actual proof of the advantages of synthetic outside certain applications and longer oil change intervals. It also depends on the synthetic oil you're using. Redline, Amsoil and a few other expensive oils are the only "true" synthetics (Esther or PAO based). Most synthetics are dyno-based, although Pennzoil is making some from natural gas. Anyway, you can easily run dyno to 5K and beyond. If you're worried, run it up to 7500 and send it in for an analysis.

[Timberridge]

Synthetic is still derived from crude oil, but processed with more hydrocracking (refining). This produces a base that flows better at low temperatures yet doesn't break down at higher temperatures. So when they say 0W-20 they're really describing the range of the base, not VIs. And that's why the change intervals are longer.

The 90's were the golden era for synthetics. Mobil was making true synthetics without any crude based group III oils. The polyol esters never came from crude oil, and the PAO's were all synthetically manufactured from ethylene. The only pure synthetic applications left are turbine oils and compressor oils. The reciprocating engine oil world today is a murky mix of all sorts of group II and III, with oil mfgrs just arguing who's group III is better, but they are all sub-par to what was being produced in the 90's. Whether that even matters in a water cooled Toyota 4 Runner engine which never revs above 5000 rpm whose oil is changed every 5-8000 mi is debatable.

As far as leakage goes with synthetics, you only had to worry about that when you had 90's era fully synthetic oils and older cars whose seals were not designed for synthetics. Polyol esters shrink rubber seals and the PAO was neutral in that regard, so the net effect was seal shrinkage. Today's group III "synthetics" don't have this effect and seals are all capable of coexisting w/synthetics.

[LHutz Esq]

You have your own lift!

I wish.

Although I have a brother with a lift....

and skills.

Which is probably better than me having a lift with out the skills - but I am learning

[Ted Striker]

@ timberridge - other than the mobil jet stuff, I didn't realize there was "pure" synth for automotive applications.

I'm not actually on BITOG, and my post above is really the sum total of what I know about the subject. A friend who works at the local refinery told me what 'hydrocracking' is.

[Timberridge]

@ timberridge - other than the mobil jet stuff, I didn't realize there was "pure" synth for automotive applications.

I'm not actually on BITOG, and my post above is really the sum total of what I know about the subject. A friend who works at the local refinery told me what 'hydrocracking' is.

In another life I worked extensively on this stuff so I'll geek out a bit on this topic.

The genesis of pure synthetics came from WW2 when the Germans couldn't get the real deal so they manufactured synthetic oils and fuels via Fischer-Tropsch reaction. Later the South Africans (Sasol) did the same when they were embargoed. Sasol developed a bunch of the technology that the majors later used to make synthetics. Jet oil is 100% synthetic polyol ester based as an ultra refined group 3 oil can't withstand the extreme temps in a turbine.

The best synthetics for piston engines use an alkylated naphthalene + PAO combo. A special catalyst places the CH3 group on the naphthalene in just the right spot on the ring. Back in late 90's Mobil developed a 2000 cst PAO which was so expensive to produce it was only used in a line of F1 motor oils and some women's cosmetics. All those AN+PAO+Polyol Ester formulations were 100% synthetic basestocks.

[Todd Zander]

yea well, saabs are born from jets so youre a proponent of synthetic in those applications i take it.

[Ted Striker]

In another life I worked extensively on... AN+PAO+Polyol Ester formulations.

Sounds a helluva lot more challenging than putting the new cover sheets on the TPS Reports, but I'm guessing the rounding errors were harder to bank.

[Timberridge]

Sounds a helluva lot more challenging than putting the new cover sheets on the TPS Reports, but I'm guessing the rounding errors were harder to bank.

Oh, no doubt.
But that gig required travel which was ok when I could roll up to the airport daily lot 1 hr before a flight to Singapore or Paris. To do the same today would take years off my life.

I enjoy my new challenges, like trying to fit the cardboard end caps on the old printer cartridge and getting it to slide into the return box properly, etc.

And of course, this place.