Last post on Nov 21, 2013 at 7:47 AM
You are in the Toyota Prius
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Toyota Prius, Engine, Fuel System
#85 of 105 slick 50 not needed
Apr 07, 2007 (7:37 am)
i used to use it but it is not API or ILSAC certified...mobil 1 is excellent oil and slick 50 would dilute it...i would use wal mart oil at 1.50 a qt (2.99 for syn, a great deal) over slick 50 anyday...wm oil is also GM 6094M approved, not all oil is...someone made a good point about oil companies spending God knows how many millions of dollars researching their products opposed to slick 50s budget...automakers dont reccomend it
#86 of 105 Re: slick 50 not needed [chetj]
Apr 07, 2007 (8:26 am)
"Back in the day" when slick 50 actually added Teflon, it did work wonders. I added it to a Subaru (the old push-rod flat four). Before adding I needed a wrench to turn the engine when adjusting the valves, after I could do it by hand. Slick 50 were forced to change their formula. I heard via the grapevine they were cut off from using Teflon. I tried it once after the change and it did nothing (to another vehicle).
Just use Mobil 1, which is a good synthetic oil, or if you're really enthusiastic, try Royal Purple. I think it's the "better" type of synthetic. From reading several forums it appears use of synthetic will not result in measurable fuel economy increases in the Prius. Perhaps any improvement is buried in the "noise" of background variations.
#87 of 105 Mobil 1 may not add mileage, but adds piece of mind
Apr 07, 2007 (11:13 am)
True, no increase for MPG will be seen with Mobil 1 in the Prius, and you really wont see any in any other car for that matter, this isnt the reason to use a synthetic. The true purpose of a syn is much better protection than any dino oil. Over time Dino breaks down in all factors, additive packaged, lubricity, holding suspension etc. Synthetics can last much longer in Lubricity and suspension, two key factors in the use of oil. Lubricity to keep the parts free moving, and suspension to carry the waste particle of combustion to the filter where it is removed. In addition, the additive packages last longer due to the properties of the synthetic blends. The additives help bind to the metal parts, adding to their life span. Zinc is one of them, ZInc is a babbit material on bearings, and having zinc in the oil helps deter from the wear(at least that was how it was explained to me in class, ASE Cert) that occurs. With Dino, the lubricity goes away after time, due to the compressions the molecules go through with each rev of the crank, Synthetics have more resistance to breaking down from compression. What Mobil 1 can do for the prius is extend the oil life from 5000 miles to 10000 miles with just a filter change at 5000 and topping off the oil. Some guys who have diesels have a bypass filtration system installed and change their oil every 15-25K miles with nothing my oil changes every 5K miles and topping off the oil. Big savings when you have 4 gallons of oil to change out, but not realy that much with the prius.
#88 of 105 Re: Mobil 1 may not add mileage, but adds piece of mind [acdii]
Apr 07, 2007 (1:31 pm)
Well, actually my 2001 Pathfinder has a 10% increase in fuel economy with Mobil 1. Perhaps it only shows up on larger less fuel efficient engines. The increase in fuel economy pays back the extra cost of the oil three times over in the 6000 km change intervals (stock recommended change intervals). I will not extend the change intervals.
Don't get me started on the silly "fuel efficient" oils (5W30) the Pathfinder came with new. Warm engine, idling, I hear rumbling (oil film breakdown - crankshaft touches bearings). Never heard it again once I switched to 10W30 (proper viscosity) oil. Sometimes people think too hard.
#89 of 105 Lighter oils
Apr 07, 2007 (2:44 pm)
There is a reason manufacturers are recommending the lighter weight oils these days. It helps them meet CARB specifications, that basically is the only reason. Engines have tighter tolerences today as well, so lighter oils work better in the newer engines, but is not needed. One thing to be aware of with Synthetics, dont use them in an old engine with 100K on it, or you might find yourself burning oil when you didnt before. Synthetics have tremendous cleaning powers, probably the reason you saw an increase in MPG. WHen you put this in an old engine, the carbon deposits behind the rings will dissolve, loosening the rings and giving them a larger gap, then you start to burn oil. Newer managed engines will less likely have this problem with lots of miles on them, but can still have similiar results, just depends on how well the engine was maintained and how it was driven.
#90 of 105 Re: Lighter oils [acdii]
Apr 08, 2007 (8:01 am)
I doubt it was carbon on the rings in the case of the Pathfinder. It was the third oil change from new (18,000 km). On the first oil change I went to Penzoil 10W30 (fixed the rumble when hot and idling - in fact I did the first change because of that 500 km early when I first noticed it). Used the same oil on the second. On the third went to Mobil 1 10W30 to see what all the fuss was about synthetic (this was back in 2001 - yeah, I'm slow to adopt "bandwagon" things) . Saw the 10% improvement, and it has remained at the improved fuel consumption rate ever since (I stuck to Mobil 1 10W30). I keep detailed records.
I've also seen (heard) the viscosity breakdown rumble on other vehicles using 5W30 oil (non-synthetic). Only when the engine is hot and idling. Scary stuff hearing the bearings loose material! With the other vehicles it happened a long way from home and I couldn't do anything about it right away except raise the idle. With the Pathfinder it happened in my garage, and I changed the oil right then!
#91 of 105 Re: Lighter oils [pathstar1]
Apr 08, 2007 (12:11 pm)
In your case, no, carbon build up is not an issue, the carbon issue is on older engines, especially pre fuel-injected engines. In your case though I bet it was a number of factors that showed your increased fuel economy, the first being you hit the magic mark where all the parts are working in harmony. The second being the better lubricity of the Mobil 1. Your tires may have also hit their mark where the wear patterns on them give them the least rolling resistance. Some happen right away, others take some time to wear in.
#92 of 105 Re: 05 Ford T-bird syn Oil and conv. top care [thundrjet]
Apr 08, 2007 (8:15 pm)
Mobil 1 0w-20 is what I use in my Ford. They want 5w-20, and this is an official substitute. Have been using Mobil 1 since '86 - no problemo.
Never fold a wet soft top, don't leave it out in the intense sun ( Texas ), and do not use unapproved cleaners/detergents. Ford has a list of approved products.
#93 of 105 Re: Lighter oils [pathstar1]
Nov 19, 2007 (11:39 am)
Just a clarifying note...you are talking about two oils of the same operating weight. 30 weight. The fact that one is a 5w and the other a 10w contributes nothing to their breakdown (at least not in the length of time oils are normally used in an engine). All engines can only benefit from using the lowest winter weight available. Meaning the first number in the name. 0w-30, 5w-30, and 10w30 in a good synthetic oil like mobil 1 all perform the same at operating temperature (like a 30 weight). The first number is how it acts when at room temperature. And then, the lower the number the better because it will flow through your engine faster on startup (in both hot and cold weather).
A 5w-30 (vs. 10w-30) oil will not make an engine have knocks or other oil starvation sounds on startup. Just the opposite. You are more likely to hear that from the heavier oils because your oil pump can't pump the thicker oil as easily to your engine components. Use a good synethetic oil of the lightest weight your vehicles owners manual recommends. That is usually a 0w or 5w. I don't know of any modern engines that recommend a 10w although they can be run in hot weather. It's just not nice for your poor engine to have to try and pump that 10w on a 32 degree day. Do your Pathfinder and change to 5w-30 (or even 0w-30) in your preferred synthetic. Easier on the engine that 10w-30, even in hot weather, but especially in anything less than 50 degrees.
On a note unrelated to viscosity or weight. another reason synthetic is better because it leaves a film on internal parts, after shut-down, longer than conventional oils, so it is easier on an engine at startup (which is when, arguably, all engine wear occurs).
Though some drivinge mileage increase may be apparent in certain engines, most of the mileage gains are from the time of first startup and then the miles put on until the engine warms up. This is also why, in many vehicles, the mileage improvements, when using a synthetic vs. conventional oil, are higher or more noticable in the winter time. Of course the biggest mileage killer in the winter time is people idling their cars for 15 minutes before they leave. Park your car in your garage (rather than having it full of junk) and think how much gas the country would save every winter day! hehe.
#94 of 105 Re: Lighter oils [chadx]
Nov 19, 2007 (12:49 pm)
Actually, you are correct in theory, but in practice, with non-synthetic oils, breakdown of the oil film did occur with 5W30 in the Pathfinder and a previous Landcruiser. Once I switched to 10W30 -standard- oil (non-synthetic) film breakdown did not occur. This film breakdown never occurred at startup, only when the engine was hot and idling. A rough rumbling/grinding sound that would start after a few seconds of idling.
I currently use 5W30 in my Prius and don't see any evidence of breakdown, but I'm using Mobil 1.