I apologize now for the lengthy posting.
I have two cars where I am considering to run thicker oil:
2000 Escort: 67K miles. Second M1 5w30 OCI to go 7000 miles. I will post UOA results in the next month
1997 1MZ-FE Toyota V6 in my 1990 Celica: ~48K. First two OCI's with M1 5w30. 3rd and 4th OCI RL 5w30 OCI to go about 7000 miles. This UOA is shown here:
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=002110
The Escort is my girlfriend's car which she drives for her daily commute(~12 mi round trip) and makes 4-6 800 mi(round trip) excursions to visit her family in northern California. This explains the high mileage. I switched her over to M1 to extend the OCI's out a bit. I change the filter halfway through.
Assuming that I'm with this lovely lady for the long haul, I've got this crazy notion to keep the car around to for the simple purpose of allowing my kids to have a car to learn to drive. No offense to anyone that owns one, but the Escort, to me, is a disposable car and as such it only makes sense to me to keep the car till it dies. In short, I'd like it to last another 20 years. Crazy, I know.
Once the car breaks the 100K mark I am considering changing the oil out for something thicker to reduce the wear on the engine. Is this a bad idea?
As for the other vehicle, my Celica, these engines are known to sludge, and I don't know if thicker oil will help or hinder that problem. If I did run something thicker, would RL 5w40 make any difference or would 10w40 make more sense? I occasionally "race" my car at open track events but other than that, I have a relatively passive right foot. I have oil pressure and temp gauges installed and here are some of the readings:
Around town:
High idle pressure: 85psi
Normal idle pressure: 25psi-20psi
Normal oil temps: 180-200
Track:
Hot track temps: ~260
Hot idle: 20psi
High RPM hot pressure: ~80psi
I am planning to install an oil cooler to bring down the temps at the track. My daily commute at this point is merely 5-10 minute so I usually let the car warm up a couple minutes to at least get the oil temps up a bit. Even then I rarely break 180. I participate in track events twice a year.
A conversation on another message board made me think about this a bit more:
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My Post that is a response to some comments in a separate thread:
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To avoid cluttering the other thread and throwing it off topic, I wanted to address some of my comments here:
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5.11 (HTHS Viscosity, mPa-s @ 150ºC ASTM D 4683) vs 2.99
Again, correct. It's easy to turn a 5w30 into a 10w40 though...
Faster to return to the pickup? Probably not. Lower volume of oil being pumped, certainly so... More oil in the pan? Maybe. Install an accusump if you are worried
No, it's not always better, but it is under most circumstances. I think the point I was trying to make, which got lost in translation between my scatterbrain and keyboard, was that it's pefectly safe, and better in my mind to run a higher viscosity oil than what the manufacturer originally intended when you increase the duty cycle of your vehicle. Stepping up 1 grade step isn't going to cause engine failure. You'll lose a bit of horsepower, see higher oil temps, but will benefit from added protection. Stepping down one grade step might possibly cause failure if your oil pump cannot deliver the volume requirements of the lower viscosity oil in order to maintain a wedge.
I agree, but I would feel extremely comfortable with extending the OCI to over 5000. To know for sure - get your oil analyzed and post the results for discussion. Remember - oil changes occur because the oil loses it's ability to suspend foreign matter, not because it "wears out"
Absolutely not. No advantage whatsoever.
Hope that answers everything, criticism welcome....
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Ultimately, I am just wanting second opinions on the statements made by the other guy and if my comments have any validity.
quote:
Running 5w20 weight in any engine is f*$&king stupid unless you live in in the tundra. Fuel economy numbers, yay! Lubrication? Boo!
quote:
15w50 Mobil 1 has better relative viscosity retention than 5w20 Mobil 1, or any other 5w20 for that matter. I run 15w50 in my Audi with 101k on the stock turbos with an "abusive" driver that's seen -6*F, and 118*F, 12,000 miles between oil changes, and it doesn't consume a single drop of oil. 15w50 will suck up some horsepower, but it gives you the luxury of running higher oil temps without worrying about breakdown. I spec 15w50 for every build I perform unless there's a special circumstance where the bearing clearances require 5w20. And that's very rare. Wayne's evo has 95 pounds of oil pressure on a cold start, and the accusump takes care of any "startup oiling concerns"
quote:
I never said 15w50 is thicker than 5w20 - what I said is that over it's service lifetime, 15w50 won't lose viscosity like 5w20, especially when high temperatures, high rpm, and extended service intervals are involved. BTW - Mobil 1 15w50 outperforms nearly all "motorcycle specialty oils". When I say M1 15w50 outperforms any 5w20/30, I say that based on experience, not conjecture. 126,000 mile 500 rwhp supercharged 97 cobra engine run on 15w50 vs stock 99 GT run on 5w20 with 55,000 on the clock. Cobra = Eagle rod, GT = Powdered metal rod. You decide whether or not my comments hold water: (images not posted) PS - that blue car in the pics runs 10w60.
quote:
Honestly, it's hard to say. I have driven the S4 in -6*F, which included a cold start - it was kind of hard to start that morning - something I could not attribute to oil because I don't know what condition my battery was in with that kind of temperature extreme. On edit - the clarify, it was a slow crank, and fired up right away. Yes. It's a tradeoff, because engine oil works by forming a hydrodynamic wedge between surfaces to provide lubrication. You gain lubrication benefits, but lose horsepower through oil drag. Oil doesn't do its job at startup because there is no hydrodynamic action on startup. Under these conditions oil is only protecting through film lubrication, because the oil molecules act like magnets and stick to ferrous metals and each other. To further explain how oil "works" in an engine: Viscosity pulls the oil between the two components, such as a piston and a cylinder wall, journal and bearing, etc, and forms a pressurized "gap" of oil. This is totally and 100% completely different than "film lubrication". The pressure increases with viscosity and speed, providing better lubrication by preventing scrubbing contact (assuming your machinework is perfect). Yes and no - for instance, Wayne's EVO motor had about .0035" of oil clearance on the mains and rods. Factory spec is greater up to .0045, and factory spec oil is 10w30. - My Cobra engine (and the one shown in the picture) had .0012 on the mains and .0022 on the rods. Ford spec'd 5w30, and later 5w20 for fuel economy reasons. Both engines had coated piston skirts, the Ford having Hypers, and the EVO having Forged. The clearances were much larger on a bore size to clearance ratio in the EVO, but were suitable enough to run 30w when hot - either way, here's what it boils down to - both pistons have coatings on the skirts to reduce startup wear, allowing the manufacturer to reduce the viscosity requirements because the piston skirts can now physically touch the cylinderwalls and not scrub the precious crosshatch off (in very extreme oil starved circumstances - please note that piston coatings are another type of film lubrication, not nearly as effective as hydrodynamic lubrication) Indeed. The engine burned oil, was run low, air was pumped through the oiling system, and it started knocking. Why did it burn oil? Because the lower viscosity oil does not provide the same hydrodynamic lubrication because of the lower viscosity, and subsequently the oil control was not present because the engine essentially wore out it's oil control mechanisms before it's expected life cycle was over. The guy only drove the car 2 miles each way to and from work with short trips. People give me **** all of the time because I play in the upper RPM band all of the time - what they fail to understand is that the lubrication is BETTER at higher RPM, and you'll see less wear over a longer period of time. Audi also uses a high idle strategy when cold to make sure there's sufficient pressure right away to start hydrodynamic action. Furthermore, to prove how important and how much more efficient hydrodynamic lubrication is, let's analyze how most engines fail when they run out of oil, listing the failure mode progression in an overhead cam engine that loses oil pressure for an extended period of time: A) rod bearings go out and you develop a knock B) cam journals suffer and starve C) main bearings go out Why? First, the engine needs oil pressure to force oil out to the rod bearings through the gundrilling in the crank. They essentially starve first. Next, the oil drains back through the block, still trickling oil on the mains. The oil is drawn into the bearing, where the crank motion continues to hydrodynamically lubricate the bearing. The cam journals are starved in this drainback process, and well, **** goes downhill from there. To answer your question regarding the variable cam timing - a lot of variable cam timing systems rely on oil drag to retard the cams for higher RPM action. Some systems require electronically switched hydraulic pressure to actuate the mechanism. In both cases, the higher viscosity oil will cause faster engagement, and slower disengagement. The disengagement lag is probably negligable, a few hundred more milliseconds, if that. Hope that answers all of your questions.
quote:With that, I have some comments/questions regarding engine wear and vehicle use: 1) As I understand it, the most engine wear occurs at initial start up. If that is the case, wouldn’t thinner oil propagate more quickly reducing wear? Wouldn’t thinner oil heat more quickly (though as stated, thicker oil would have a higher peak temp) which would be ideal for a vehicle driven short durations? I would imagine those factors also contribute to the use of thinner oils besides the obvious fuel economy increase due to reduced drag. 2) What’s the possibility of a thicker oil blowing seals due to oil pressure that is too high? With 5W30 my engine also hits about 95 psi and maxes the 100psi gauge if the engine revs past 3000rpm when the oil is cooler than 140degF. Once hot, idle pressure is about 20psi. Do leaks mean wear or can oil leaks be mutually exclusive to engine wear. In other words, if the thinner oil lubricates better on average, but the thicker oil reduces consumption, which is better? 3) For extended OCI’s (oil change intervals) thicker oil probably does last longer if one compares organics to organics, etc. However, one of the benefits of synthetics oils is the ability to maintain viscosity for extended OCIs, not to mention the ability to maintain its level of active additives. 4) Judging by the comments from the folks over at http://theoildrop.server101.com the SAE viscosity rating is not as critical as the HTHS(High-Temperature, High-Sheer ) rating. For example, RL's 0W20 has an HTHS of 3.5 while M1R 0W30 has an HTHS of 2.9. I would think these numbers would be more critical for those of us that drive hard. 5) Viscosity stability has a lot to do with the difference between the cold and hot ranges of the fluid and not just the actual viscosity. A straight weight oil would maintain it’s viscosity best. A 10W30 would have better viscosity stability compared to a 5W40 of equal make. At least, that’s what I understood from various googling and folks at the aforementioned site. 6)Would a thicker oil reduce fluctuations in oil pressure significantly? Would this matter on a daily driver where oil pressure does not fluctuate? So is thicker oil always better? I’m really not sure. I think it depends on vehicle usage. If one drives their vehicle harder than the average Joe, then thicker oil is probably not a bad idea. What about open track? Maybe a weekend of racing means draining the "street" oil and filling with something thicker to reducing the chance of shearing the fluid or oil pressure fluctuations. Also, I think it depends on the type of oil and how long you intend to extend ones oil changes. For a low mileage (<100k mi) daily driver, I believe standard Costco special, Chevron Supreme, in the recommended OEM rating will probably work just fine as long as the oil changes are done religiously at 3000 miles. Anything that detracts from that, I’d think a good synthetic would offer the lubricity needed at startup, protect against shearing, and allow for extended oil changes, without the need to change viscosities. For example, let’s compare Mobil 1, Redline, and Chevron Supreme all in the 5W30 flavor: Type – Pour Point{C} – 40C Vis -- 100C Vis – Cold Cranking Vis {-30C} -- HTHS{150C} M1 : -- -45 ----- 56 ---------- 10 ------------ N/A ----------------- 3.08 RL : --- -45 ---- 67 --------- 10.9 ------------ 60 --------------------3.3 Chev -- -36 ----- 64.8 -------- 10.8 ----------- 57 ------------------ N/A Looking at 15W50 M1: -------- -45 -------125 --------- 17.4 --------N/A ------------------ 5.11 Compare that to Chevron Supreme 20W50 and 10W40 20W50---- -29 -------- 176 ----------19.0 -------80{@-15}------------- N/A 10W40---- -34 --------104 ----------14.8 -------64{@-25} ------------ N/A Judging from these numbers, a synthetic would flow almost as good as organic 10W40 and offer high temp viscosity similar to a 20W50. For a car that is driven hard with minimal starts and stops it would probably work quite well. However, my concern would be how well the oil flows when it is cold compared to lets say 10W30 which would have a cold viscosity of about 74 in Chevron’s case. For folks that drive only a couple miles a day to work, would the high temp viscosity advantage be of any use? An example would be my girlfriend's Ford Escort. She is averaging about 17k miles/year {800 mile trips home 4-6 times a year} and that means a lot of oil changes. As she doesn't race the car, a hot viscosity of +15 would not be needed. I'm sure the oil barely reaches operating temperature on her 15 minute daily commute. However, I switched her car over to M1 5W30 since it offers better flow at low temps, and lasts longer than standard oil. She is at about the end of a 7000 mile OCI and I am going to send out a sample of the used oil to be analyzed. An interesting test would be to run the standard recommended oil for an interval and then run a thicker oil and compare the analysis reports on both to see how the wear numbers changed, if at all. If there is significant wear on the Escort I may experiment with thicker oil like 10W30 or maybe 5W40. Jury is still out. Just interested in some feedback. ++++++++++++++++++++++++ His response: ++++++++++++++++++++++++ Well, in theory you're right, but Mobil 1 15w50 has better cold pour properties than conventional 5w30, so you're still getting really good startup protection at butt-cold temperatures. Not as good as 0w20 Mobil 1 per say, but that might be crossing the line when you look at how startup wear occurs. But it's harder to conceptualize all of the wear in an engine on start:
Usually higher viscosity oils require larger oil coolers because the shearing effect increases the oil temp and bearing temp. Usually not an issue, but on a car without an oil cooler, it's potentially disastrous. In the summer I wouldn't hesitate to run 15w50 - in the winter I'd probably stick with 0w40... I wouldn't worry about the K03 inlet. I'd worry about the outlet...
- Bearing wear (an oil wedge suspends moving parts)
- Ring and cylinder wear (oil film lubricates until everything is up to temp and a wedge is formed)
- Camshaft and valvetrain wear (cams don't spin fast enough to create an oil wedge, so they rely on film lubrication)
5.11 (HTHS Viscosity, mPa-s @ 150ºC ASTM D 4683) vs 2.99
Again, correct. It's easy to turn a 5w30 into a 10w40 though...
Faster to return to the pickup? Probably not. Lower volume of oil being pumped, certainly so... More oil in the pan? Maybe. Install an accusump if you are worried
No, it's not always better, but it is under most circumstances. I think the point I was trying to make, which got lost in translation between my scatterbrain and keyboard, was that it's pefectly safe, and better in my mind to run a higher viscosity oil than what the manufacturer originally intended when you increase the duty cycle of your vehicle. Stepping up 1 grade step isn't going to cause engine failure. You'll lose a bit of horsepower, see higher oil temps, but will benefit from added protection. Stepping down one grade step might possibly cause failure if your oil pump cannot deliver the volume requirements of the lower viscosity oil in order to maintain a wedge.
I agree, but I would feel extremely comfortable with extending the OCI to over 5000. To know for sure - get your oil analyzed and post the results for discussion. Remember - oil changes occur because the oil loses it's ability to suspend foreign matter, not because it "wears out"
Absolutely not. No advantage whatsoever.
Hope that answers everything, criticism welcome....
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Ultimately, I am just wanting second opinions on the statements made by the other guy and if my comments have any validity.
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Happy New Year!
