Synthetics?

I was the OP in the thread 2009Prius linked. I did switch to Mobil 1 5W30 last year and have put about 20K (2 oil changes) since. I never went to lower weights. I noticed a slight (1/2 qt per 10K) consumption (though that could have been there before when I was doing 5K changes). Last summer I noticed only a slight (if any) increase in gas milage - but that could have been due to a change in tires (Michelin Energy Saver A/S).

One reason that I changed from Castrol Dino oil was my personal boycott of BP. Castrol is owned by BP! I still feel that way!

 

Hi 2009Prius, in my last car, at about 100k miles, a black cat crossed its path. After that, it started using more oil. What are the chances of that being just a coincidence?

But now, from Patrick Wong's example, I do see that my statement was not quite correct. If the oil is changed to synthetic during the time when the engine is beginning to use more oil due to normal wear, then the oil consumption will not return to its previous level if it is changed back. But it will also not be worse than if synthetic had not been used.

I respect Patrick and don't want to misinterpret him or to put words into his mouth, but he didn't actually say that his problems were determined to be caused by a change to synthetic, did he?

Patrick, perhaps you might wish to elaborate your valued point of view on this detail?

Yes, in the distant past, with a '62 Mercedes, a '77 Chevy, an '82 Ford and a '76(?) Honda XL250 motorcycle. I don't remember the details of oil consumption or leaks, but in any case not out of the ordinary for older cars. Admittedly, they are not really comparable to a modern Japanese machine.

I started with 10k mi., and increased to 15k mi. based on used oil analysis and my mild operating conditions.

If it's worth it depends on your individual circumstances. Economically, I would guesstimate that you save only a little bit if you also extend your oil change interval. For me, the convenience of fewer oil changes, and the very, very slightly better fuel economy are worth it.

 

Actually, the oil consumption on my 2004 started when I switched from 5W-30 mineral to 0W-20 synthetic. I attribute this to use of the thinner viscosity, not necessarily the switch to synthetic oil. When I switched back to 5W-30 (now using synthetic) the oil consumption continued although at a lessened rate.

I recently bought a 5 qt. jug of Castrol Syntec 5W-20 synthetic oil (to be used either in the Mustang or HiHy) from Walmart, on sale for $21. My thought is that BP will need revenue to pay for all of the damage that company caused to the Gulf Coast.

 

Patrick:
If you had switched to 5-20 wt. Synthetic you would have used oil as well! The way you tell this it makes people believe it is because of the 0-20 wt. Oil, when in fact it is do too the difference from 30 viscosity and 20 more than the lower #'s?
Cheers
Hal

 

Hi Hal,

Yes, it is likely that use of 5W-20 would have resulted in a similar outcome as the use of 0W-20.

 

There are basically two ways that synthetics are thought to contribute to oil leaks (talking about external oil leaks rather than internal oil consumption).

1. Because they flow more freely they may get past a seal or gasket that's in poor condition more readily than a conventional oil. This however is likely to also be true for a lighter weight conventional oil.

2. The extra cleaning action of the synthetic dissolves some sludge or gunk that was previously preventing a seal or gasket from leaking. Considering that many convential oils also clean very aggressively then this same thing might happen anyway if you shifted to more regular oil changes or an oil with higher detergent qualities or otherwise internally cleaned the engine internals in some way.

Also this should not really be too much of an issue if you have maintained the car well with regular oil changes, even if it has 100k miles on it.

Another thing to remember is that the line dividing synthetics from "regular' oils is becoming less distinct these day. Many "conventional oils contain a significant amount of synthetic components to meet the new tighter standards like API SN.

 

North American light duty oil standards are significantly lower quality compared to the European ACEA standards. Even A1 assumes the minimum normal EU oil change interval of 12 months or 10,000 miles

ACEA also has specific requirements regarding the amount of ring land deposits, and especially "gellation" or cold black sludge. Cold ring sticking is caused by different oil breakdown problems than high temp ring land fill deposits

The ACEA also readily accepts there are different quality motor oils and grades them accordingly. Hence ACEA A1, A5, A3, etc. The Bx are used for light duty diesel engines, since a significant amount of the passenger car fleet in the EU runs on diesel engines.

Some of these oils, such as A3/B3, are intended for severe service and extended oil changes, typically 24 months or 20,000 miles

Finally, in the EU, the auto maker is entirely free to set their OWN oil standards.

API has much lower expectations. First, API magically assumes that ALL oils are exactly the same. There is only one grade assigned, such as SL, and every oil from the cheapest generic to the most expensive synthetic has the same label

In the mind of the consumer, this creates a lot of confusion.

Second, the API assumes a much shorter oil change interval. Typically, this is 6 months or 5,000 miles

Third, cold ring sticking and deposit control are much more loosely controlled than by the ACEA

Up until around a decade ago, the API allowed a motor oil to "pass" if it thickened 500% in service. If it allowed significant gellation or cold weather thickening. And if it contained barely enough detergent to last 5,000 miles

 

API == American Petroleum Institute == American Petroleum Industry.

About API

 

Jay, do you think my ~10k/6 month oil and filter change interval using a GF4, ACEA A1/A5 'synthetic' is reasonable for normal driving, or would you recommend something different ?

 

In the EU, a basic oil is ACEA A1/A5 for the normal 12 month or 10,000 mile oil change interval there. You should be fine

Is there oil consumption between oil changes?

I ran Mobil 1 0W-20 starting in 2005 in my Prius. With oil change intervals up to 10,000 miles and the dealership filter, the used oil analysis was fine. No detected oil consumption either

 

Why not just 0W-40?

 

Thanks Jay.

Happily, no oil consumption.

 

I used to run Mobil 1 European Car Formula 0W-40 in my 2007 Toyota FJ Cruiser with excellent results, as confirmed by used oil analysis

Unfortunately, that particular oil is no longer available locally.

I was able to find the made in Germany Castrol Syntec 0W-30. Have also had excellent results with this oil too.

The German Syntec 0W-30 is blended for durability and performance, not for fuel economy. It is considered a "thick" 30 oil, so it doesn't carry the Fuel Economy label

No difference whatsoever for the 4 litre V6 in my FJ. I did try the 0W-40 and 0W-30 in my Prius, also no difference

 

I am certain I will switch to a 0W30, but I think I will wait awhile to see what 0W20 users experience over time.

 

1. Original specifications for the truck back in 86 called for 10w30.

2. I don't recall seeing any 0w40 in my area, so I went with 10w40.

 

I have 2004 prius, it has 266000 mile on it and it consume oil about 2 quart every 2000 mile with synthetic. and as far as fuel concern, about 40 Mile a gallon. Than I saw a youtube for the old engine problem, to use regular oil/non synthetic and put STP for smoke problem. I did it and now I get 47 mile a gallon. It improve in mileage. I drove about 300 mile.

 

As others have said quite eloquently, it really comes down to personal preference. I just use good name brand dino oil & change every 5k miles (per the scheduled maintenance). Increasing the change interval may put your warranty as risk if a problem develops down the road. The way I see it, if you stick to the manufacturer recommended 5k change interval, there is no need for synthetic oil.

But again, there are no inherent right or wrong answers. Do what you are comfortable with and what seems to work for your car.

 

Most mechanics do not suggest this, but then you have to have a hybrid to really know.