New here...5W-20 question

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Hello. I'm new to the forum, and I'm new to knowing more about my car. Just started doing my own oil changes, and modifying different things for better peformance or protection. As I started to do research related to my own car (a Mazda6S) I started learning more about engine oil, transmission fluid, air filters, etc. One thing I've noticed is that there seem to be two camps of people concerning 5W-20 oil. Those that think a 20 weight oil is too thin to protect the engine, and those that don't. I don't want to start a big debate since I'm sure there have been many, but I would appreciate if someone could outline the basic arguments/evidence for and against 5W-20 oil for me. From what I've read it seems that modern synthetic or blended 5W-20s seems to protect just as well or better as any 5W-30. Why do so many people seem to think 5W-20 is ineffective if manufacturer's are recommending it? And for those that may ask, yes I did do a search of the forum. It didn't yield much.
 
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quote:
Originally posted by Breitman: And for those that may ask, yes I did do a search of the forum. It didn't yield much.
That is hard to imagine. I have a 2004 6i and have been using Havoline 5w-20 but I'll switch to M1 0w-20 at the 10,000 mile mark. Will probably bounce between Havoline dno 5w-20 and the M1 depending on weather and if I'm doing a track event. Do yourself a favor and look at the used oil analysis reports here with M6s and M6is. Lots of them courtesy of Crossbow and mazda6tech.com. Based on what I've seen with the Mazda 2.3/3.0 engines and Ford v-8s, I feel very comfortable using a 20w oil...especially during warranty period. But certainly do read those reports and check the mazda6tech site. Between BITOG and 6tech, you'll be more confused than ever [Big Grin] . Seriously, it's worth a read.
 
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Originally posted by MolaKule: quote: What vicosity would be required at 100C (212F), 5.25 cSt SAE 5-20 125C (257F), 5.25 cSt SAE 30 150C (302F) respectively? 5.25 cSt SAE 40 The above are considered minimum viscosities at the temperature specified as per an SAE/GM paper on minimum lubricant films in engines. End Quote Actually that 100C temop is below SAE 20 Range: 5.6 - 9.2 Those are for basic Dino Oils. Motorcraft is a Synthetic Blend available for only $1.42 at WalMart. It is 8.9 cSt @ 100C according to a recent VOA and is also a Synthetic Blend. Also there is a boatload of UOA's from Mazda 6i's in the UOA section is you search. That means at least virgin it should be good up to about 250F oil temp. It also is more shear stable than most 5W-30 SL oils and I have seen many analysis were 5W-30 is thinner coming out of the crankcase than the 5W-20 is. Ford also recommends 5w-20 for Severe Service ie Police Cars which are not figured in their CAFE (Corporate Average Fuel Economy) so they would have no reason not to go to 10W30 if there was something to be gained. FRPP (Ford Racing) Rep said: Street: 5W-20 Drag: 5W-20 Auto-X: 0W/5W/10W-30 (Try to pick a thin one like Mobil 1) Track: Below 80F 10W-30 Synthetic Track: Above 80F 10W-40 Synthetic Gene P.S. I have beat this subject to death and finally convinced myself that it is sufficient on the street.
 

Jay

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quote:
Originally posted by Breitman: ... but I would appreciate if someone could outline the basic arguments/evidence for and against 5W-20 oil for me...
The one camp against 20-weights argues with endless theories, but no evidence, that 20-weights can't protect well. The other camp puts up UOA after UOA that show--plainly--that it does protect well in the engines it's recommended for. That's pretty much the argument.
 
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quote:
The one camp against 20-weights argues with endless theories, but no evidence, that 20-weights can't protect well. The other camp puts up UOA after UOA that show--plainly--that it does protect well in the engines it's recommended for. That's pretty much the argument.
Doesn't sound like much of an argument to me. [Wink] [ June 26, 2004, 12:49 AM: Message edited by: ZiTS ]
 
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Bottom Line Is This (And I'm trying to be as fair and unbiased as possible): 5w-20's came about as being the recommended viscosity by manufacturers solely because of the desire to achieve higher fuel economy ratings. With that said though, the manufacturers (well, Ford) were smart in establishing a baseline spec. that enabled "regular 'ol" 5w-20 to be a darn good oil...much better than a "standard" 5w-30 has to be. UOA's PROVE this viscosity to be entirely appropriate in street-driven applications. BUT, even with the higher-quality specification, 5w-20's (PCMO's, not racing lubes) lack the viscosity and shear/film strength to be an ideal lube in a racing application (in an engine that isn't being rebuilt as a "true" racing engine would be...). For this vehicle, I'd recommend Mobil 1 0w-20 with a Motorcraft filter.
 
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Jelly, I agree whole-heartedly with everything you said. For once, the consumer may benefit from a company making vast changes in order to save money! Everything has a purpose, and there is a purpose for everything. 5w-20 has shown to be an excellent viscosity, but it is by no means the end-all-be-all for motor oils. Then again, neither is 10w-30, 10w-40, 5w-30, 0w-30, 5w-40..... [Cheers!]
 
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The one item that I will admit is a fair point for the nay crowd on 5w20's is a lack of long term records on engine reliability. The war stories often go "I always got over 150 or 200 thousand miles using 10w30, so therefore I don't need to change or thin oil is inferior to my results... However, we faced (and still face in some circles on this board) the same types of fears against using a dino 5w30 when they became regularly recommended by manufacturers in the late 80's for year around use. Yet I personally haven't seen any evidence that this change resulted in a long term durability decline, but have driven three vehicles to 162,000 miles (and sold it), 163,000 miles (donated to charity), and approaching 250,000 miles and still running fine on nearly exclusively dino 5w30's...
 
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i use 5w-20 as well in my honda. and if your like me, nervous about using 5w-20, but want to stick to the manufacturer recommended viscosity, then id say use the best 5w-20 you can find, which in my opinion is red line. gives you some peace of mind
 
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