[DougR]

Just ran across something while searching about oils on a Mazda3 forum for my wife's car.

By all means do the 5w-30 vs 0w-20 comparison. But do remember that mobil1 5w-30 sheers below a 20wt oil after just a few thousand miles. Its not sheer stable.

http://www.mazda3forums.com/index.php?topic=6527.0

its reply 12

So this person is stating that mobile1 5w30 is not sheer stable and will break down even lower than a 20 weight oil after a few thousand miles. Is there any truth to this?

I have been picking up the mobil1 5w30 at the local BJ's wholesale because I can get a case of 6 for ~$25. I realize that 0w40 is the best thing, but I cannot seem to find that oil anywhere in my area.

 

[earthworm]

Just ran across something while searching about oils on a Mazda3 forum for my wife's car.

By all means do the 5w-30 vs 0w-20 comparison. But do remember that Mobil 5w-30 sheers below a 20wt oil after just a few thousand miles. Its not sheer stable.

http://www.mazda3forums.com/index.php?topic=6527.0

its reply 12

So this person is stating that Mobil 1 5w30 is not sheer stable and will break down even lower than a 20 weight oil after a few thousand miles. Is there any truth to this?

I have been picking up the Mobil 1 5w30 at the local BJ's wholesale because I can get a case of 6 for ~$25. I realize that 0w40 is the best thing, but I cannot seem to find that oil anywhere in my area.

Maybe some truth, but, IMO, the meaningful difference would not amount to a hill of beans !
I was at the Wal-Mart yesterday and found that all the Mobil 1 10-30 (5 qt jug) was all sold out !!
Plenty of Quaker State and Pennzoil synthetics, however..

I would recommend Mobil stocks..

 

[DougR]

Well according to their website Advance Auto carries 0w40 in the store near where I work, I am going to drop by on my way to work. I guess if I can find it, that is the best of both worlds.

 

[Slaab4life]

I would recommend Mobil stocks..

It trades as Exxon/Mobil. A friend of mine has some stock in it. I don't even know how many times it has double and tripled in value since he received it as a child....

I nearly shate myself when I say that relatively cheap price of Mobil1 at Wal-mart. Might have to pick up a jug of it this afternoon, if I can find it! Whats recommended? 5w-40 or 0w-40 sufficient? Anything special things to do when switching to synthetic oil from dyno?

Heres something I heard a few weeks back about Mobil1 synthetic. It all started out as Castrol (I believe) purifying/filtering dyno oil so much that they labelled it as synthetic. Mobil got angry that Castrol was doing that while Mobil was spending big money actually producing synthetic oils. So Mobil sued Castrol over the synthetic labelling and lost... So what does Mobil do after loosing? They stop producing genuine synthetic oils and go to the purefying/filtering dyno oil method to the point where it is said to be synthetic. Has anyone else heard this before?

I understand Voll-Synthese is a very good synthetic oil to go with?

 

[DougR]

We'll I have heard that even full synthetic starts as highly purified dino at some point. It would seem then that a full synthetic, in not truly full synthetic. I always see the voll-synthese on eeuroparts, but had no idea about quality, so I did not pick it up(although eeuroparts does not seem to be in the business of selling junk).

 

[DougR]

On your edit. Apparently switching to full synth can cause/expose some slight leaks due to breaking up deposits and exposing places that dino could not get through.. So if you don't have any leaks at 130k, you may have some after switching to dino. I think I got one after switching, but seems to have subsided quite a bit, and I have never had any noticable loss of oil. Still with the leak I would rather have it then be on dino. If it's the rear main seal I will take care of it at clutch change. I really have not got around to fully checking it out, because it just is not that big of a deal.

Also, if you do switch, you may want to pick up two jugs. I noticed that my oil is really dirty after about 1500 miles. From what I have read the full synth probably broke up a lot of deposits in the engine, and it is now in the oil. So I plan to do another change this weekend.

 

[Slaab4life]

Well, technically, the engine has 116K on it, and no drips on the driveway! <knock on wood> I understand too that synthetic oils have advanced greatly over the years, especially now with a gasket conditioner to help prevent leaks. Just prior to my last oil change I put some Seafoam through so hopefully that had broken up some deposits within the engine (though if the cleanliness of the valve train is an indicator for the rest of the engine, hopefully I'm pretty well off).

What are you using for oil filters? I typically use the $5 Bosch (I know, I spoil my car!), but have heard that Purolator Pure-One is the way to go because of the check valve it has. Thoughts?

 

[DougR]

I currently am getting the saab OEM from eeuroparts, but I think that is just a bosch right? Maybe I should step out and try something else next time though.

I have heard about the gasket conditioner too. And in some ways I think that may be what happened to me. At first my car was leaking quite a bit. After a while I found that the car was leaking less and less overnight, and in amounts that did not touch the ground. Sometimes I am finding that it has not leaked at all.

Another great x factor for my car seems to be the fact that I got the last engine drain plug gasket from the dealer, and judging by the gasket that came from eeuroparts, the dealership gave me the wrong damn gasket. The one they gave me is thinner and has rounded off edges. The one eeuroparts sent does not have rounded edges, and seems to be thicker. I will have to compare them more when I get the old one off the car. It seems to me that a gasket with rounded edges could surely be allowing a small leak.

 

[DougR]

Picked up 5qt of 0w40 mobil1 at advance auto. They are reg 4.99, but the guy gave me the preferred discount(don't know if you usually need a card), and it was 4.44 a qt, so not a bad deal at all. Sure I am getting 1 less qt than I would get of 5w30 at BJ's, but it may be worth it. Now I would be in heaven if bj's started carrying 0w40(I should ask them about it).

 

[rotate]

We'll I have heard that even full synthetic starts as highly purified dino at some point. It would seem then that a full synthetic, in not truly full synthetic.

Full synthetic does not start from mineral oil. It's "synthesize" typically from alcohol.

 

[TGA78]

There are lots of great posts in various forums about synthetic oils. I know there is some great info to be found on the 3SI forum. Some very knowledgeable people from all walks of life came together over there. They debated every angle of the synthetic and synthetic blends available. I highly recommend checking it out.



I know companies have been working to improve the problems people have with the synthetics drying out the seals on cars that ran dino oil for 100k+ miles. However a year ago when I was still working for the performance shop I had still seen no change. I can’t tell you how many rear main seals and valve seals I have changes on cars where the owner decided to switch to a synthetic after 100k miles. The problems usually seem to appear less the 15k after the switch was made. So yea I love synthetics, they have made me lots of money over the years.



I have seen much better results when people switch to a synthetic blend. But even the blends seem to dry out seals on some cars. Personally I still use dino oil in everything I drive. Until I buy a car new from the dealer running on a synthetic I will not switch. Dino oil has never done me wrong. Sure it looks worse after 3k then synthetic after 5k. With nearly 150k on my 94 Saab right now. I pulled the motor hoping to find the time to rebuild it. Not that anything was wrong with it mind you. It just had 150k and I want to upgrade the turbo. The engine ran on dino oil its whole life and looked really good when I opened it up. The oil pan had a very thin layer of sludge on the bottom. Not bad at all for dino oil and 150k miles. Anyway with engines lasting for 200k+ miles running on dino oil I really see no reason to change. Unless your looking for an excuse to change the seals in your engine.

 

[philosophicaldreamer]

I know companies have been working to improve the problems people have with the synthetics drying out the seals on cars that ran dino oil for 100k+ miles. However a year ago when I was still working for the performance shop I had still seen no change. I can’t tell you how many rear main seals and valve seals I have changes on cars where the owner decided to switch to a synthetic after 100k miles. The problems usually seem to appear less the 15k after the switch was made. So yea I love synthetics, they have made me lots of money over the years.

I am just curious: why would seals in cars that have over 100K miles dry up when using synthetics whereas the same phenomenon would not be present with low mileage cars?

Thanks,
janusz

 

[JMarkert]

I am just curious: why would seals in cars that have over 100K miles dry up when using synthetics whereas the same phenomenon would not be present with low mileage cars?

....actually there are a couple other theories:

1 - synthetics are more slippery, so they can sneak their way into smaller gaps than dino oil.

2 - they dissolve sludge which is blocking leaks on marginal seals.

I'm not sure which of the theories is true, but my old volvo 240 leaked like a sieve when I put mobil 1 in. No real problem with my saab though (minor seeps), maybe because it's a decade or two newer.

 

[philosophicaldreamer]

....actually there are a couple other theories:

1 - synthetics are more slippery, so they can sneak their way into smaller gaps than dino oil.

2 - they dissolve sludge which is blocking leaks on marginal seals.

I'm not sure which of the theories is true, but my old volvo 240 leaked like a sieve when I put mobil 1 in. No real problem with my saab though (minor seeps), maybe because it's a decade or two newer.

Thanks for your explanations. My Saab does not seem to leak even though I do use synthetic oil, and my Volvo is too new, I guess, to leak too.

Ta-ta, j.

 

[DougR]

Just put in the 0w40. The car is really purring like a kitten. It is certainly much quieter than on the 5w30. I will have to see how it drives after dinner.
I also noticed that the dealership gave me the wrong washer last time I was in, and this probably helped cause the leak I had on the drain plug. The washer they gave me was rounded. The one eeuroparts sent me was flat.

also as a warning from the stupid. After oiling up the filter, make sure to put the lid back on the qt of oil. I didn't, put on the filter then crawled back out from under the car and knocked it over with my arm. What a frickin mess.

 

[bkrell]

Just make sure before believing something as gospel, you have confidence in your source. www.bobistheoilguy.com has a ton of folks discussing oil. I can't say whether or not they know what they are talking about, buut a lot of folks there do used oil analysis.

FYI, my 97 2.0 turbo has 185,000 miles or so and has been on a steady diet of mobil 1 as long as I have had it (109,000 miles) and it doesn't have a real leak yet. Every now and then there is a slight weap around the plug where a distrubutor would go in the n/a engine, but it is marginal and could be easily sealed if it ever really bothered me.

Turbocharged engines are very hard on oil due to the high heat. I would use a good synth no matter what.