nottoday

So I bought this 2001 Coach 3 years ago. It runs great but burned exactly 1 quart of oil every 1K. Along with changing the PCV, I started using Mobil 1 high mileage 5-30, changing it every 4k. I am now on my third change and at 5100 miles and have not even burned one quart of oil on this change! I am sold on this oil, no more carrying and extra quart of oil around, and no more nasty blue smoke gagging the neighbors. Try it!

Oro

If you are not starting the vehicle a lot below 0F or -5F, try the M1 10w-30HM. It is more oil and less viscosity modifiers than the 5w. Also much stouter than the 5w and it's cold pumpability is quite good. The 5w beats it really only in very cold. I use about 1/2 qt in 7,500 miles and the car has 276k on it now. You can probably now start stretching out your oil change intervals. I have seen a lot of UOA's of this oil in this engine out to 10k miles and it holding up nicely. I call the ball at 7,500 to 8k myself.

The Valvoline Maxlife Full Syn. 10w-30 also has some really impressive stats on it's base oil (particularly Noack). And of course, has the highly-regarded Valvoline HM add. pack. I would also think that would work great, too.

danielTRLK

Not in my experience. A 10W will put more friction and gum up this engine pretty quickly, especially considering it's old. If anything consider running a 0W. I have seen many UOA that show otherwise, very few of these engines can do 10K, clean. Rather than strictly looking at NOACK, consider the viscosity index as more important in this case.

Oro

I'd have to say vast experience with this engine in the hands of millions of owners shows that 10w oil isn't an issue.

The key thing is not 10w or thick/thin in most cases. It's base oil quality. You are going to get a better base oil with a narrower grade band in most cases if you compare apples-to-apples. It's easy to pluck stats from dino vs. blend vs. full synthetics. So we will have to talk about apples-to-apples in similar grade, high-quality oils. In fact, a full synthetic 10w-30 is, in some cases from the top manufacturers, pretty much a monograde oil with little to no wax and VIIs in it and it simply is pure enough that it flows well enough to meet 10w test specs. A 0w oil MIGHT be very pure in it's base oil, but it's going to be full of VIIs to get to 30w specs at operating temperature. And it's the VIIs that shear and burn and cause problems faster.

Not above 0F. The 10w-XX oil is only going to be thicker really below 0F compared to a 0w-XX, and virtually identical at most any temp above. And by going to a thinner oil for very cold climates, you give up base oil thickness and rely on little rubber and plastic polymers (but massive in relation to oil molecules) to get your oil "up" to the proper thickness at operating temp. These are what shear and break-down more quickly over time and "gum up" things to be honest.

Noack is a very useful measure because, unlike the winter rating or the pour point, there are no chemicals you can sprinkle in to the oil blend to alter it. It's a very good proxy for base oil quality.

nsghtbrwry

Whoa, did not know about NOACK, I gotta do some reading.

Got an anecdote though: I've always changed my 1MZ cars at 5k (I drive a fair bit of highway); even though I go to 10k or even 15k on other cars, I didn't want to deal with the sludge issue. Oils I use are Mobil1, Pennzoil Platinum, and SuperTech.

On my '02 Sienna (just rolled over 90k), I decided to try going to 7500 with Mobil1 5W-30 full synthetic and a Wix filter. I filled it up with the 5 quarts, and keep in mind that it never burned oil before (not a drop). Checked it every 500 miles, and no oil burning up to 5000. At 5500, it started burning oil, and by 7500 it was down 1.5 quarts to 3.5. I pulled the front valve cover and sure enough, it was lightly sludgy (could also see it/scrape it under the oil cap on the PCV baffle). I changed out with another 5 quarts of Mobil1 and a Wix filter, and it stopped burning in the next 1000 miles (lost 0.5 quarts before it stopped), and the sludge is gone from under the oil cap.

nottoday

I really wasn't talking about the weight of the oil, I was just saying how the high mileage mobil 1 stopped the massive amounts of oil being burned and no more blue smoke clouds.

danielTRLK

Not sure where you're getting this info from. Having done thousands of UOA, I can tell you quite the opposite. It's the thicker oils that shear faster. MOFT is a huge component, trust me I don't pluck stats from data sheets. A 10W is going to be hard on this engine, not questions about it. Increasing the film thickness is only going to lead to more friction, heat and wear.

NOACK is a good measure, but not the ultimate measure. This is not true, at least not in my professional experience. A 10W is going to be very hard on start up and hard on the pump, it is far thicker than required and exceeds MOFT required. Sort of like the engineers strictly looking at HTHS and setting a weight based on that. You don't give up film thickness or strength by going to a lighter weight, quite the opposite, lighter weights with good bases hold up far better.

Oro

To be clear, a 0w-30, a 5w-30, and 10w-30 are all gong to have the SAME or exceedingly similar characteristics at operating temperature. The cold-starting value has nothing to do with it. Saying that a "10w-xx" is hard on the engine at normal use because of the 10w rating is like saying 2+2 = Fish.

The elements that shear are generally the MASSIVE VII molecules and not the oil molecules themselves. Both contribute to viscosity loss, but in very different amounts. An oil with less VII will be more stable. This should not be overly confusing,and UOAs bear it out.

danielTRLK

It is start up that is the primary concern, getting proper flow to the EP areas of the engine is important, 10W30 is going to put a lot of pressure on the system. Lexus doesn't openly say it but on internal documents for the RC F oil selection, they even state the same thing. You can run a 10W30 but they want it back down to a 5W the next change because they don't want a bunch of warranty claims. It takes a few minutes before you get to operating temperature, during that time you're nailing the oil pump and failing to get oil up top in the EP areas. UOA has proven time and time again, lighter weight + super high VI = less wear, friction and more efficiency. And I don't do Blackstone style UOA.

UOAs, the thousands I've done, have shown the opposite. The thinner oils hold their grades much better, even when the oil is the same. This is not because VII or VI's are sheering, Mobil has one of the best viscosity improvers that really don't sheer even when fuel diluted and even their heavier weights have trouble holding, it's due to the viscosity index, which is far more important than a lot of other measures in an engine. The oils I run have a VI of 210-240. Most off the shelvers are 150-175. The VI is critical in function and one few people will ever bother with. You also have much better ring seal with a thinner oil, contributing to less combustion by products in the crank case which we both know is what ends up killing these oils.

Why you would go to a higher than required HTHS and MOFT is not something understood by many in the industry. Toyota just acknowledged the other day in an article that they're going to be looking at more than just HTHS for oil weight selection. A thinner oil that can maintain MOFT is what one would want.

Do you work in the oil business?

Oro

What is the viscosity difference between a 5w and 10w at 40F? It must be substantial to result in the delta P you are describing as so catastrophic. But it's "0" for the oils we are discussing.

I'm thinking this is a bizarre trolling exercise...

Time to pull the plug...

danielTRLK

What are you talking about? LOL First if you even had access to the "Bible", I'd be interested in talking.

These oils, a 0W30 and a 10W30 will have a 20~ centistoke difference at 104F. It would be even greater at 40F

At 40F the difference is close to 100 centistokes for 5W vs. 10W.

Calling me a troll is interesting........Please pull your plug.