Best conventional oil? Syntec 0w30 vs. other 5w30 synthetic?

last time I check the German Syntec was more expensive than Mobil1 I haven't see anyone post the UOA on the Syntec either. For the few dollars more I just use synthetic. If I can't afford that I really should have bought an old beater and ignored the hybrids.

 

I wouldn't bother with synthetic if you are going to change the oil more often than the required 5K.

 

Any good quality oil of the correct weight and API service rating should be just fine. I use Mobile 1 and I'm probably wasting my money on synthetic. But when it gets out of warranty, if I still own it, I will start changing it every 10K instead of 5K miles.

Jayman is kind of an oil expert so check for his posts on the subject. I think he said he was using 0W-20 synthetic in winter, but he lives somewhere in the far North where they have real winters. Where I live it doesn't get much colder than -10 degrees F. and 5W-30 is OK.

EDIT: Just don't use the "oil in a drum" that a lot of dealers and oil change places sell. Jayman had some of it tested and it was really bad as I recall. Buy oil in plastic bottles and take it in if you have someone else change it. I have done that and the dealer didn't mind at all.

I haven't seen any objective test data lately that compares different brands.

 

I've used the "bring your own oil to the dealer" approach when I had my Civic some years back and I always wondered if they still use the drum oil in my car and keep the synthetic that I brought for their own use in their personal cars. It was one of those dealerships where you couldn't watch the work due to the insurance liabilities of the shop (i.e. they did not have a window where you could watch the work being done). Am I just paranoid? How do you know they used the oil you brought in instead of the drum oil? Of course if you watched them changed your oil, then you're sure.

 

If you are going to use synthetic; one, go with an extended replacement schedule, usually 7500 miles but as many as 35000! Amsoil 0-30 is the best on the market and is good for 35000. you just have to change the filter half way through. I did this and at the oil change my oil was still somewhat translucent, not totally black. I think some of that is due to the extremely low stress that is put on the 1.5L engine even when running at full speed.

 

in the greater PHX area is the perfect application of synthetic motor oil, with your summer temps of 110-115F I don't really think I'd use anything but. Just for it's greater protection at extreme temps.

 

Mobil 1 is an average performing GIII synthetic oil. The Castrol Syntec 0w-30 that has the 'Made in Germany' label is an excellent oil but is too thick for the Prius application. The viscosity of most 30 weight oils is about 10.0 cSt at 100C (212F). German Syntec 0w-30 is 12. something. Mobil 1 Xw-30 oils are about 10. something.

We have some Prius' running in fleet service with Motorcraft 5w-20 (a synthetic blend) which is 8.8cSt at 100C with 5k oil change intervals with good results over that past three years. I am running RedLine 5w-20, in my 07 Prius, with a 9.1cSt at 100C.

With 5 years experience with the Prius and a vehicle count of 211 we have had good results with oils between the 8's and 10's in dynamic viscosity at 100C. We stopped using Mobil 1 about a year ago because of just average results and a big price hike. It performs well for a 5w-30 but performance is no better than many other 5w-30 oils. The German 0w-30 Syntec is an excellent oil, maybe the best on the market but I believe it's too thick for this application even for Phoenix in the summer time in the middle of a heat spell with stop and go driving with the a/c on full blast and full of passengers. Our choices are made by info from maintenance records and lab analysis and financial considerations. Taking all this in to account, Motorcraft 5w-20 is an outstanding performer.

Just a note about German Syntec. It is a completely different oil than the other Castrol Syntec oils. They share nothing in their chemistries. In the right situation it is one of the best performing oils, price no object.

 

I can't answer the question about using 5w-20 vs the recommended 5w-30, for sure. I do know that if there is an oil related failure it's up to them to prove that you caused it. The usual reason to deny a claim is no proof that you changed it often enough. We are having good luck with Motorcraft 5w-20 in the Prius and also in places where 5w-20 is the recommended oil. For some reason this is a very good oil.

As mentioned in a previous post, I would not use any bulk oil in a car that I owned.

And another note. A bunch of Prius nuts got together for a mileage contest-rally. All the top placers used Motorcraft 5w-20, a synthetic blend or Red Line 5w-20, a synthetic. The winner on their 500 miles trip got 72.5mpg, hand calculated, not the display. That's way beyone me.

 

<div class='quotetop'>QUOTE(LongRun @ Dec 29 2006, 03:40 PM) [snapback]368276[/snapback]</div>

I thought that, by definition, no xW-30 oil could be "too thick for the Prius." The German Syntec is on the high end of the range to be 30 weight, but it is still in the range. Otherwise Toyota would have had to say a specific maximum cSt at 100C rating for the oil in the range of 30 weight. And I'm not sure that I would use anything less than an xW-30 oil, as Toyota demands. Maybe the xW-20 weight could fail under high heat conditions? Jayman has pretty much proven that the 0W-30 oil should not be a problem with the warranty, in fact there are some 0W-30 oils which are better than 5W-30 oils. Once again Jayman might be able to give more insight to which specific oils.

Also, you can get the Motorcraft 5W-20 oil at WalMart, which I'm sure would be cheaper than at a Ford dealer. I used to use it in my F250. I also see that Motorcraft has a synthetic 5W-30 oil, but I have never seen it anywhere. Maybe you would have to special order that at a Ford dealer. I would hate to think about the price.

I have read about it on the Internet, so it must be true, that Ford has denied engine warranty claims because 5W-30 oil has been used in V10 engines instead of the called for 5W-20. Of course, that is substituting an oil which is thicker for the called for thinner oil. I don't know how it would work the other way around. But you can be sure that if Toyota wanted to, they could prove that you were running 5W-20 oil instead of 5W-30 oil like they call for.

 

I used the German 0W30 from August to December in Chicago. The Prius gave me some of my best MPG using it, even though it is on the thicker side of a 30 weight oil. I am now running Mobil1 0W20. The 0W20 I can verify has given me a plus 1-2MPG over any previous oil (German Syntec or Mobil1 5W30). I may run 0W20 year round, but if I don't then back to the German Syntec.

Wayne

 

<div class='quotetop'>QUOTE(Devil's Advocate @ Dec 29 2006, 12:40 PM) [snapback]368249[/snapback]</div>

I also run Amsoil...I've benn doing the 5K schedule...but trust the Amsoil product...I guess I'll never really know unless something happens...In the older cars I used to have, I could tell the difference in the sound of the car, but not with this one, I'm too busy trying not to let the engine run!!!

 

Does anyone have any proof that Ford denied a warranty claim because the owner/operator used 5w-30 vs 5w-20 in a V10. I asked the Ford people we deal with and they can't find one. Do be careful of what you hear on the Internet about warranty claims. You might hear only part of the story and not all the information used to settle the claim, including things like good will or fraud.

A statement was made that there are some 0w-30 weight oils that are better than 5w-30 oils. This begs the reply, better for what application, and what is the definition of better. A tough question to answer, for sure. If you have the answer, there are several jobs waiting for you, good ones, too.

The comment I made about German Castrol 0w-30 being a thick 30 weight still applies. I think this Prius engine does not need an oil over 10.0cSt at 100C. And about using a good 5w-20 blend you must know that uoa's we have done on 5w-30's show that after some use, they shear down into the low end of the 20 weight range before the next oil change. One reason we are having good results with Motorcraft 5w-20 is that it stays put for 5 to 8k miles. At close to the 5k interval that we follow, we find that Motorcraft 5w-20 has a higher viscosity, rated at 100C than most conventional 5w-30 oils. These numbers come from lab work, not speculation. Most 5w-20 oil, we find, perform better than their 5w-30 siblings. We've had MC 5w-20 at 5k miles range from (in the bottle it's 8.8), 8.6 to 8.4. Many of the 5w-30's start around 10.x and at 5k miles are around 7.x. So it really is a tough question, can you use an oil that is a little thinner or thicker than a target spec. Don't expect too much help with questions about oil from your dealership. They have some stuff in a barrel and that's what they recommend for your car, what ever it is. If they get a different barrel, you'll get a deverent recommendation.

 

If your dealership though 0w-30 was to thin when compared to a 5w-30 I'd worry about letting them do anything to my car. And again, anyone that accepts mystry oil from a barrel and shot through a gun is not taking care of their car. If you keep it three years or less then who cares, otherwise do something else.

 

<div class='quotetop'>QUOTE(LongRun @ Jan 13 2007, 08:09 PM) [snapback]375310[/snapback]</div>

With all due respect, every car dealer I have had experience with has told me the same thing: "a 0w-xx will blow up your motor blah blah blah our dealer tote bin 5W-30 is best blah blah blah."

There is a lot of disinformation from dealerships regarding motor oils. Once you mention anything with a "0" in it, they run away screaming. Even the official TSB from Toyota hinted at this, that a 0W would cause "smoking" and "oil consumption" but a 5W-30 wouldn't. Pure crap.

As the first three oil changes were complimentary for me, I let them change the oil. I believe the vast majority of car buyers take whatever disinformation the dealer hands them at face value, unless they are in a position to accurately offer a rebuttal. How many car buyers do you know of who will manage to sample the garbage tote bin mystery oil from the dealer to *prove* what s*** it really is?? I did so to track down the mysterious Na readings. Or how many car buyers routinely test their oil to determine how it is holding up? I do.

I'm sure you'll agree with me that the average car dealership is a ripoff from day one, starting with the purchase price. It goes downhill from there, and quite frankly I doubt it makes any difference if the car is foreign or domestic. Again the average car buyer doesn't have the time, training, or resources to become an expert in car repair, tire technology, or oil technology.

The average car buyer really has no choice but to accept at face value everything the stealership tells them.

Even if the car buyer acts on a hunch, and takes along their own oil say a synthetic or semi-synthetic, they have no guarantee whatsoever that the stealership won't put the good oil in the trunk of his car, and put the garbage tote bin stuff in the customer car.

Locally, Canadian Tire is the worst for that. Watch them like a hawk.