What engine oil to use?

[webguy]

I am expecting delivery of a 2006 Pri in the begining of Jan. I have been reading the threads here regarding the different engine oils owners are using. I have seen everything from regular oil to Mobil 1 synthetic.

What is recomended by Toyota? Will using sythetics void any warranties?
What are the advantages to synthetics, since I have not used them in any of my previous cars? What have all of you found to be any mileage benefits from the different oils, if any?

Your help in understanding this is appreciated.

Greg

[efusco]

Originally posted by webguy@Oct 11 2005, 05:19 AM
I am expecting delivery of a 2006 Pri in the begining of Jan.  I have been reading the threads here regarding the different engine oils owners are using.  I have seen everything from regular oil to Mobil 1 synthetic. 

What is recomended by Toyota?  Will using sythetics void any warranties?
What are the advantages to synthetics, since I have not used them in any of my previous cars?  What have all of you found to be any mileage benefits from the different oils, if any?

Your help in understanding this is appreciated.

Greg

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There are a lot of old posts on this topic. I did a lot of personal research in making my decision.

Toyota recommends just regular old oil (aka Dino oil or Mineral oil) . It's cheaper, works fine and should do a perfectly good job of protecting your ICE.

I chose to go with Mobil 1--I admit that in part it was b/c it just 'felt' right to use a technically advanced oil in a technically advanced car. But also b/c the net environmental impact of synthetics is slightly better than that of mineral oil. It also offers superior wear and heat protection--but I honestly don't think that is likely to be an issue with mineral oil.

There are no warranty issues.

The clear advantage of dino is that it is cheaper if you do oil changes at the same intervals (5k miles) with both. Some folks stretch their changes to 7500-10k miles with synthetics like Mobil 1 b/c of the superior life and wear protection...but to me that does bring in the warranty issues. If I did have an engine failure and couldn't show that I followed Toyota's maintainance schedule I think I could have problems. I might extend the service intervals once I'm out of the warranty period for the ICE.

Some feel that the lower viscosity of Mobil 1, particularly those who chose to use 0W20, offer improved fuel efficiency and better cold weather mileage. I'm a tad skeptical that this is measurable, but if you want another excuse to spend $5/quart instead of just $2/quart you can add that to the list!

[tochatihu]

You are going to be very happy next January, Greg!

Toyota recommends their 5W30 conventional oil. IMHO, conventional oil is fully adequate for 5k mile oil change intervals (OCI). But if you buy your oil at the corner store, note that there are a bunch of capital letters that need to appear on the oil bottles you buy. See those in your soon to be seen owner's manual.

I use Mobil 1 synthetic, and do extended OCI. Used oil analyses are our best tool to know how far it is safe to go in that area. Have noted no obvious changes in performance, fuel economy, or anything else. But I am buying and recycling less engine oil. Approaching 80k miles, it seems unlikely that an engine warranty dispute could ever arise with Toyota. We now have evidence that Prius is very easy on its engine oil. I *know* that Tochatihu is squeaky-clean inside.

I suppose everybody wants high mpg in their Prius, but switching to synthetic oil is not the magic bullet. Learn the driving tips posted around here, combine short trips whenever possible, don't drive on underinflated tires or overfilled engine oil, keep the engine air filter clean, don't let your parking brakes drag, and stick to the posted speed limits (or a bit slower, if you can stand it). I do my best in these areas, and still only average 46 mpg in 2001 Prius. You will probably to better.

[IFixEm]

Originally posted by webguy@Oct 11 2005, 04:19 AM
I am expecting delivery of a 2006 Pri in the begining of Jan.  I have been reading the threads here regarding the different engine oils owners are using.  I have seen everything from regular oil to Mobil 1 synthetic. 

What is recomended by Toyota?  Will using sythetics void any warranties?
What are the advantages to synthetics, since I have not used them in any of my previous cars?  What have all of you found to be any mileage benefits from the different oils, if any?

Your help in understanding this is appreciated.

Greg

[snapback]139395[/snapback]

Congrads on the new Pri. All Lex/Toy/Scions start life with normal 5w30 oil from Mobil 1, relabled as toyota oil.
The use of higher grade oils (synthetic or blend) will not void any warranty.
Synthetic oil was developed in the 70's to keep constuction equipment running in the bitter alaska cold durring the oil pipeline days. Normal oil would near instantly gel in the cold.
The benifits do not always out weigh the costs. I'll use our shop as an example.
LOF: 26.95 interval 3000 miles
LOF blend: 34.95, interval 4000 miles
LOF synthetic: 54.95 5000 mile interval
Oil is not as important as the change interval, I have no proof, just 25 years experiance on cars.
At our shop, blend gives the most bang for the buck, but I do feel full synthetic sticks to components longer than normy or blend.
The most important thing I can tell new car owners is to overchange the oil....use good stuff and change it early. I run Mobil 1 full synthetic in my 03 IS300 and my sweeties 99 celica. Miles are 21000 and 52000. Never a drop leaked, inside of the 99's valve cover looked new, not just clean, new at 30000 durring the valve lash checkup. I do both rigs at 3500 mile intervals. Not 5k, not 7k, not 15k (yes I see that all the time).
The big thing about the Prius specificaly is only use 5w30 and do not overfill it. Since the Pri starts and shuts down often, it gets dirty faster because the oil rarely hits 200 degrees like other cars. The heat helps cook off moisture and acids.
More than once I have had Pri's with 4 qts from Jiffy lube and a P3191 engine code. Nomal cars do not monitor amperare varriations to the starter, but the Pri does. It looks at MG1 and MG2 torque and rotation. If it turns to slow because the oil is 15-40 or 1/2 qt or more over it sets a MIL.
I hope this helps some,
Regards, Mike

[Bill Merchant]

Thanks for your advice, Mike, and welcome to priusChat.

Are you a Prius tech? It's interesting to hear you say the Prius oil gets dirty faster. What distance on the highway do you think a Prius needs to drive to get to 200° oil temperature?

[IFixEm]

Originally posted by Bill Merchant@Oct 12 2005, 12:16 AM
Thanks for your advice, Mike, and welcome to priusChat.

Are you a Prius tech? It's interesting to hear you say the Prius oil gets dirty faster. What distance on the highway do you think a Prius needs to drive to get to 200° oil temperature?

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Lots of variables here Bill, but most cars require a 2000+ rpm modest load, for 20 minutes or so to realy heat the oil. This helps to vaporise normal moisture from condensation and purge it out the PCV. Unfortunately the Pri likes to go easy on the ICE. In town it is hard to get oil above 150 degrees. The oil gets dirty fast on intown drivers. We service more than probably any other dealer in the U.S. because the State, county and city all own pri's. Intercity transit, fire department, DOC, DOT, and AG office all use them as well as Evergreen coll. The oil is always water thin, and nasty black with a heavy acidic smell.
I recomend to all my customers who listen to do oil changes early and often, if you are going to skip maint. , skip brake checks , coolant flushes and tune-ups etc.
Regards, Mike

[jayman]

In city driving, especially here in Winnipeg, all cars are rough on oil. At -40 you can drive all day in stop and inch traffic and the oil will be lukewarm at best.

I first started using synthetics 25 years ago for the superior cold temp protection and longer engine life. I never expected fuel savings and have never seen them either.

I still have a 1984 Ford F-150 I bought new, now it's out at my hobby farm. Around 530,000km on that 302 V8 and the compression is still 130 lowest. Most of it's life it ran Mobil Delvac 1 5W-40, changed every year or two, with filter changes every 3-4 months.

At 18,000km I switched my 2004 Prius from the dealer 5W-30 (Rebranded Mobil 5W-30?) to Mobil 1 0W-30. No difference in fuel consumption but I much prefer the 0W-30 for our winters.

It should be at 24,000km before the end of the month. I'll do a used oil analysis as there is a lab here in Winnipeg that can test used oil. I'm curious about the moisture and TBN, as the vast majority of my driving is city.

[tochatihu]

Originally posted by jayman@Oct 12 2005, 10:28 AM
...I'll do a used oil analysis as there is a lab here in Winnipeg that can test used oil. I'm curious about the moisture and TBN, as the vast majority of my driving is city.

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This is music to my ears, Jayman. Please post the UOA results! The first time I took an oil sample for analysis, I took it "cold" (not following the instructions), and there was a "trace" of water present. Surely you will not repeat this rookie error.

Ifixem and Bill Merchant, my 2001 Prius with miniscanner says that 85C/185F coolant loop temp is typically reached within the first 5 minutes of driving, or 10 minutes if it's sorta cold out. Lacking an oil temp sensor, I can only speculate that the engine oil rarely gets to 200F. I realize that this can be important for chasing water out of the engine oil, but (when well-sampled) the Prius engine oil is not wet. If you have any ideas how to check this better, please post them.

Are you cold-world drivers blocking the radiator airflow during the winter? Even I do that, and most of California does not get cold. None of it gets *really* cold, at least not where the roads go.

[IFixEm]

Originally posted by tochatihu@Oct 12 2005, 12:28 PM
This is music to my ears, Jayman.  Please post the UOA results!  The first time I took an oil sample for analysis, I took it "cold" (not following the instructions), and there was a "trace" of water present. Surely you will not repeat this rookie error.

Ifixem and Bill Merchant, my 2001 Prius with miniscanner says that 85C/185F coolant loop temp is typically reached within the first 5 minutes of driving, or 10 minutes if it's sorta cold out.  Lacking an oil temp sensor, I can only speculate that the engine oil rarely gets to 200F.  I realize that this can be important for chasing water out of the engine oil, but (when well-sampled) the Prius engine oil is not wet.  If you have any ideas how to check this better, please post them.

Are you cold-world drivers blocking the radiator airflow during the winter?  Even I do that, and most of California does not get cold.  None of it gets *really* cold, at least not where the roads go.

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ECT does not equal oil temp. I should also quantify thet I live in the NW corner of the US so arizona and cali drivers can ignore the water in oil issue. Around here it is above 50% humidity for 9 motnh a year. Wet air in means more condensation develops after you park it. About the only way to check it is with a themocouple down the dip stick hole. Then again, the ICE will not see the load other rigs do.
Regards, Mike

[tochatihu]

I agree with all of your points, Mike. Please say what you have found by measuring Prius engine oil temp vs the coolant.

It is a shame that Prius comes with no facility to monitor oil temperature nor pressure! But all we know so far from UOA suggests that they have not really short-sheeted us. The ICE is fully loaded sometimes, but not very often, I reckon.

I have driven up your way a couple of times, to chat with folks at Evergreen. The faculty parking lot was full of SUVs. We have a lot of work to do yet.