BigWhiteGTP

What is synthetic blend, half regular motor oil and 1/2 synthetic? Just wondering.

Also, my car had developed a bad habit of burning off some oil upon startup. Someone mentioned it's most likely leaking valve seals that are old (86K on engine) and that they leak a bit after the car shuts off and when started up again, it burns a bit. Would running regular oil be better since maybe it's thicker? Is regular oil thicker than synthetic? Should I use a different grade oil?

Thanks.

84z28350

It all really depends on specific brand. Some just have some synthetic additives and some are more or less just a mix of syn and pet oil.

vrtc350

iTrader: (1)

From what I understand they are actually group 3 oils that are synthetic, but derived from dino juice. They are hydrocracked mineral oils.

Amsoil and Mobil 1 are true synthetic oils because they are not derived from any dino juice. Mobil filed a lawsuit against Castrol Syntec and others because the use of the term synthetic was misleading. Some companies (Quaker state) changed this to synthetic blend due to this lawsuit. If you look at the back of a bottle of synthetic oil and it says it's a group 3 based product, it is not true synthetic.

phess11

I think Mobil's new oils (5000 mile, 10000 mile, etc.) are blends of synthetic and regular oil as well.

vrtc350

iTrader: (1)

Mobil 1 and Amsoil are made from PAO stock. Others the group III synthetics are not. I haven't looked at the new 5000 and 10000 mile oils, but I don't see why they would revert back to a dino juice based synthetic. Here is an article explaining the difference.

http://www.pecuniary.com/newsletter...synthetics.html

This came from this tread. It starts out stupid but towards the end the discussion get very detailed about the difference of real synthetic and synthetic blend. This is also where my previouse statement was based.

https://www.thirdgen.org/techbb2/sho...hreadid=176753

phess11

Understand your point. I just assumed that for the 5000 mile stuff Mobil just diluted their synthetic with dino juice. Because if it were all synthetic why wouldn't it last 20,000 miles like it did 10 years ago.

five7kid

iTrader: (14)

I think this was the first link you tried to post http://www.pecuniary.com/newsletters...ynthetics.html

Synthetic blend is indeed petroleum mixed with synthetic. Of course, what the "synthetic" is, like any "synthetic" these days, is up to the blender.

AMSOIL actually makes PAO, Group III, and semi-synthetic (synthetic blend) oils. The PAO are the "premium", or best, of course. The Group III are for the quick lube industry and are intended to be 6 month or 7500 mile change intervals. The semi-syntetic are for the cost conscious, typically fleets. But, also for those who have oil consumption problems but need some of the synthetic properties (low pour point for extreme cold starts, wear protection, etc.).

Mobil 1 - I'm not sure what to think about them sometimes. When they first came out with their synthetic back in '75, people complained about leakage and consumption issues. In the early 80's, I had a high school buddy whose family owned a Mobil station that switched his fairly new Suburban over from Mobil 1 to AMSOIL because of those problems. In the early 90's, they were saying 25k oil changes were okay once you got past your manufacturer's warranty period (there's a load of confidence in your product for you - AMSOIL said if you changed per their recommendations and you had a warranty rejection, they'd take care of it). I haven't seen an extended drain ad from Mobil 1 for several years until they came out with this 5000 & 10000 stuff.

As for this question: "Is regular oil thicker than synthetic?" The answer is "No". They are rated at the same temperatures and must fall withing a certain viscosity range to be called a particular weight regardless of petroleum or synthetic base stock. However, a 10w petroleum oil will probably be thicker at -20 degrees F than a good 10w synthetic oil will be, because that's beyond their rating temperature. On the other hand, a synthetic will handle 250 degrees F better than a petroleum oil will.

You shouldn't change to a thicker oil, you should fix your valve seals. Then you can be comfortable with putting in a higher priced synthetic and not worry about it going out the tailpipe.

vrtc350

iTrader: (1)

Okay, there has been a ton of info that I have read. The most and best information has come from the links I posted in this thread. I've been around this board longer than my sig says and this seems to be a question that is asked often and in many different ways. I'm just curious as to why a sticky hasn't been made on the difference in synthetics, synthetics blends, and conventional oil. This is some really great info.

rx7speed

from what I have seen of the mobil 1 5000 and 7500 oils are the 5000 is dino juice the 7500 is a synthetic blend. that is what I saw on the labels take a look
they still sell the full synthetic to last I checked.

vrtc350

iTrader: (1)

I guess that makes sense. I just never realized that full synthetic would go that long.

contact

Some things to keep in mind,
In my opinion,

the group 2 basestocks, are a big improvement over
old style group 1 oil, solvent refined.
I just don't know how to avoid group 1,
except that group 2 seem to be marketed
with a description something like 'clear base'.

The latest spec for oil 'SM', is a downgrade
for the motorist.
The EPA is limiting the amout of phosphorus
in the oil, thus limiting the amout of
Zinc dithiophosphate, ZDDP, which is an important additive.
ZDDP is important in engines without roller tappets.
Zinc can be added to oil, with certain additives,
or look for new oil that does not meet spec SM.
Does anyone remember old Kendall oil,
if I remember correctly, the stuff had 1600ppm of
Zinc, 'SM' spec oil is limited to 800ppm.

If you can use an 15W-40oil, perhaps consider
Chevron Delo 400, although aimed at diesels,
it works great in cars.
Lots of Zinc, does not meet downgraded Spec 'SM'.\
For a car that burns oil, 15W-40 should be considered,
if the temp never goes below 40F, or so..

avoid 5w-20 oil.

I'll post more thoughts, if anyone is interested.

vrtc350

iTrader: (1)

I have found that the Shell Rotella works well. It to is designed for diesels and makes up for the lack zinc. My dad runs it in his truck. This was figured out when a friend had the #6 or #8 lobe get wiped. I can't remeber if it was the intake or exhaust.

redbird_400

I replaced the valve seals in my 89, ALL! of them were cracked lol... anyway if your going to do it yourself I would recommend the air compressor method and the valve spring remover that pushes down to compress the spring. I got a 15 gallon 4scfm 150 max psi craftsman air compressor for 139.00 (open item) from sears, well worth it.

BigWhiteGTP

Thanks RedBird. It's not on every startup, just every once in awhile. Nothing to be alarmed at....yet.

Tremo

I believe that mobil's 5000 mile oil is just group 3 dino juice. The 7500 stuff is a blend of group 3 dino and PAO synthetic. Of course their Mobil1 product is pure PAO.

Castrol and most others who claim "synthetic" really sell Group 3+ hydrocracked dino juice, which a court has allowed them to call "synthetic".

So, Mobil's 7500 synthetic blend is a mix of real deal synthetic and excellent Grp 3 dino. OTOH, Castrol's would be a mix of their Grp 3+ and some Grp 2 dino.

IMO the best synth blend would be the Mobil 7500.

I've been running Mobil1 in my 2 cars for years. It's excellent. I've recently switched to the M1 Truck & SUV oil which is a 5W-40 oil and is nearly identical to their superb Delvac1 synthetic diesel engine oil. You can easily go 10k miles on this stuff.

The oils intended for Diesel engines are really excellent and work great in gas engines as well. Chevron's Delo 400 and Mobil's Delvac are great dino oils and are highly recommended. I run Delo 400 in my lawnmower.

I have read excellent reviews of Valvoline's Synpower oil additives, as they're loaded with all the additives that have been taken out of oil.

Automobile oils are now made with CAFE ratings and emissions in mind, at the expense of engine life.

vrtc350

iTrader: (1)

I thought group 3 was the hydrocracked mineral oil. If not, then what is group 3 exactly?

rx7speed

why are they "downgraiding" oils?

one thing I have read/heard whatever though is the more addatives in the oil the more sludge that can get built up. those little things when used up cause buildup and contaminate the oil if I remember right.
though how much I'm not sure but I know from quite a few sources (even 57 I think) talked about getting better oil base stock being that it will not have or need as many addatives and that is better

rx7speed

cafe is the group that tries to get better gas mileage right?
if they are designing oil that doesn't protect the motor as long it's because pieces are rubbing together right?
wouldn't that friction decrease gas mileage?
and wouldn't that be against what cafe whats?


might be wrong I admit I'm STILL tired so not thinking to clear but that is just my thoughts right now. catch me when I'm awake I might have a different view

rx7speed

group 3 is a hydrocracked dino juice stuff


it's only called synthetic in the marketing term being I guess that it gives some of the advantage of synthetic (better then regular dino juice) but isn't truely a synthetic man made stuff.

gotta love the difference between marketing and fact. try watching the tornado with all their marketing "facts"

contact

to rx7speed,
IMO, the terms ‘group 3’ and 'synthetic’ are used in
a confusing way.
To me, group 3, is a spec for a base oil.
‘Synthetic’, used in the more general {Castrol} way, means
a certain processing step, ‘isomerization’, or something like that.
Possibly, you need this ‘synthetic step’, to get to ‘group 3 ‘ spec,
but the two terms are not the same. This ‘isomerization’ involves
rearranging certain molecules {thus the term ‘synthetic},
as opposed to other refining steps that mostly
involve getting rid of stuff you don’t want.

Tthe Epa is suppposedly concerned that the phosphorus
in zddp will harm catalytic converters..
Redline uses 1400 ppm of zinc in some of their products.
as far as ‘too much additive’ causing sludge, perhaps that
applies to detergent, which has a tricky job to do.
If someone claims that the ‘reduced xinc’ mandate,
can be ‘made up for’ by better base oil,
I suppose that is true, to a certain extent.

Wouldn’t you rather have, better base oil,
and a free hand to choose the additves,,
as opposed to the Epa choosing?

rx7speed

ok you win.

I mean this is the land of the free.... dem der gubermint dun't think so at times I rekon

Tremo

Maybe a little confusion here, let me try to explain, and I hope I'm not off base. To the best of my understanding, Group 3+ oils are hydrocracked dino juice. Hydrocracking makes the long hydrocarbon chains more resemble a real synthetic. OTOH, a Group 3 oil (no +), is just a straight, highly refined and very good dino juice, but has NOT been hydrocracked.

The BITOG forum is where you really need to go for the best info on this. They have actual petroleum/lubrication engineers there.

The reason Mobil sued is because the Grp 3+ oils are MUCH cheaper to produce than PAO, yet they sell at retail for nearly the same price. So Castrol's profit margin on Syntec is MUCH greater than Mobil's is on M1. Regardless, if you're going to pay $4 to $5 per quart for oil, you might as well get the REAL deal synthetic like M1, Amsoil, Pennz Platinum, RP, etc.

There is another newer synthetic (real), not PAO, that I believe Pennzoil is using in their Pennz Platinum oil.

vrtc350

iTrader: (1)

So what about that Royal Purple stuff that is all over Horse Power tv and Trucks? They are in bed with that stuff and I saw today that it is now available at Napa. How does it compare to all the other synthetic oils out there?

phess11

I believe that Royal Purple is "real" synthetic. The real good stuff.