5W-20 Question?

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Jul 8, 2002
Lake Anna, VA
I told the girlfriend I would change her oil today in her 99 Mercury Cougar with the 2.5 DOHC V6. Her manual calls for 5W-30 but I was wondering if there would be any adverse effects of using 5W-20 instead? She drives alot of highway miles and I am gonna run an analysis to see how the 5W-20 holds up compared to the 5W-30 in there now. I know the 01 cougar's call for 5W-20 and the engine has not changed so I guess i've answered my own question but was looking for any additional comments.
You just want to see the fireworks fly, right? 20-weight oils are the most contentious, hotly debated subjects on the board. Some folks here really have an axe to grind against them, but the few analysis results that have been posted have ranged from good to excellent. It's good that you are going to compare results by analysis. Let us know how 20-weight works in your car.
You shouldn't have a problem. As a matter of fact, both my wife's car and sister's car call for 5w30 (00 Civic and 99 Civic) and I will be putting Royal Purple 5w20 in both of them and doing oil analysis. I used to be a big hater of 5w20, but now I'm feeling a lot more confident that it can get the job done.
The technical literature I have read to-date shows a 5W20 may work out IF it has Moly or some other AW/EP addtive such as Borate esters. I think the reasoning here is that since a 5W20 hydrodynamic film is rather thin, a good AW/EP additive and friction modifier is needed in order to back-up the thin hydrodynamic film.
And from what I understand, Royal Purple has a pretty healthy dose of moly in it's 5w20 too. We'll find out soon! [Smile]
Ryan, I'd go with Mobil 1, 0w-30, which is very close to being a 0w-20. That should give you better fuel efficiency and cold starting than the 5w-30 you are currently using ....The selection of 5w-20 oils on the market now isn't that great .... [ November 19, 2002, 07:28 PM: Message edited by: TooSlick ]
Guys, I thought about this a good while today and i'm just curious how the 5W-20 will hold up, so after seeing the 5W-20 GTX analysis today I opted to try it out. Also, it was the only 5W-20 on the shelf at our local Advance Auto. I was going to go with 5w-30 M1 SS but the GTX analysis showed 250ppm Moly so it should do a fine job. I'll post the results as soon as I get them.
5W-20 is PURE sh*t. Manufacturers specify them ONLY for CAFE/EPA reasons and to increase gas mileage. use it in your engine if you want this in a few years: [crushedcar] Motorcraft switched to a synth blend 5W-20 only because normal 5W-20 thinned out to nothingness after 2000+ miles which meant the engine would wear down excessively. I would stick with 5W-30 or 10W-30 dino or synthetics. Use 5W-20 if you want this [crushedcar]
Metroplex, I used to think this too, but what proof did I have? None. Same with you. Take a look in the used oil analysis section on here and you'll see nothing but good 5w20 reports so far. It's not as bad as we all thought. I remember back in the 80s when 5w30 came out and everyone said it would spell doom. Well, it didn't. Sure, I agree that 10w30 is the better built oil, however with the way they are making oils now, you can still get long engine life with 5w30 and 5w20. The difference in viscosity between most 5w20s and Mobil 1 5w30 (or many other synthetic 5w30s) is too close to call anyways.
The reason is because the 5W-20 is a synthetic blend. Try to find a pure Group I, or II dino 5W-20 and you probably won't find any that meets ILSAC GF-3 and API SL ratings because the dino 5W-20 thinned out way too quickly. Ford knew this which is why their synth blend 5W-20 is the only Motorcraft version available. Inside sources state that the 5W-20 was chosen for EPA/CAFE and gas mileage reasons, That's IT. The same engines that were spec'd to use 5W-30 suddenly became spec'd to use 5W-20. It doesn't make sense. It's like taking your 1973 Chevelle with a 454 and saying one day it needs to use 5W-30. Then suddenly the next day you decide it can only take 5W-20. Same engine, no mechanical differences (that would require the use of a thinner oil), yet they require 5W-20. Again, very reliable sources have shown that 5W-20 isn't the best oil to use in an engine. The only reason to use it is for a slight increase in gas mileage, which gets the EPA off the manufacturer's back for awhile. Let's see how 5W-20 fares in drag strip'd and street 99-up Mustang GT. I seriously doubt it will still perform like a 20 weight after 3000-5000 miles. 5W-20 is **** thin.
I've seen a lot of oil analysis reports on Mobil 1 Trisynthetic 5w30 which had thinned out to a 5w20, and were in very hard driven cars (mainly f-bodies) and the wear metals still looked fine to me. I got alarmed by the thinning out of the oil, however wear metals tell the true tale, and if they are still good, then there is nothing to worry about. If I wasn't running Schaeffers in my Firebird, I'd be tempted to put the 5w20 Royal Purple into that car and prove that it'll handle hard dragstrip runs and extended intervals too. My sister and wife both drive each of their cars pretty hard though, so they'll put the RP 5w20 to the test for me though. Stay tuned for the results!
RyanOOTJ - good plan to test the 5W-20 in a <i>girlfriend's</i> car, versus your mother's car. I, too, will be very interested in seeing that analysis, if you're so inclined to get it done and post the results.
A side benefit to a 5W-20 oil is increased HP. Since it is a thinner oil there is less resistance in the motor. If I were to use a 20W oil I'd use Torco's MZP Synthetic 0W-20. It's a great racing oil that can be used in daily drivers, too. See: Todd, That goes against board rules [No no] Please read them [ November 20, 2002, 02:50 PM: Message edited by: BOBISTHEOILGUY ]
My question is: WHy stop there? Why not go to a 0W5 grade such as NEO Synthetic's Oils [ November 20, 2002, 02:52 PM: Message edited by: BOBISTHEOILGUY ]
Why not use Evian spring water in your engine? Its light enough, you should gain 0.000001 hp w/ that [Big Grin] If M1 TriSynth 5W-30 thinned to 5W-20, imagine what synth blend 5W-20 or dino 5W-20 would become? 5W-5? 5W-0? [Eek!]
Why do you think the 5w20 would continue to thin out? So far it doesn't look like they thin out at all, since they only have to span a smaller gap, they don't need as much VII in it, and therefore are very stable. Until we start seeing bad oil analysis results on this oil, none of us can claim that it's going to shorten the engine life at all. Sure, it is an oil mandated by CAFE, however don't let that cloud your judgement. I'm guilty of it too in the past, however you're making a judgement on this viscosity of oil without any proof whatsoever. Show me proof that it's bad.
Metroplex, A 5w-20 is essentially a 5w-30, but without the same # of VI modifier added. A 5w-20 that uses the same basestock will be more shear stable than a 5w-30, all things considered. I expect the 5w-20's to actually thicken over the course of a 7500 mile drain interval from oxidation. It is true that 5w-20's are specified mainly for small gains in fuel efficiency, but I've seen some SAE papers by Japanese engine companies that show 5w-20's with a small amount of moly perform comparably to a good 5w-30. Most of the 5w-20's are about 9 Cst @ 100C and most of the 5w-30's are in the 9.7-10.5 range, so the actual difference in high temp film thickness is fairly small.
I'd like to make a prediction (Gazing into Crystal Ball): [freaknout] [Dummy!] I think what we will eventually see are requirements for 0W20 oils with advanced base oils of esters (polyols) or of polyethers or of Ethylene Olefin Copolymers, using as AW/FM additives of moly, esters of borates, esters of calcium, Antimonies, and other organometallic dithiocarbamates such as Vanadium, Chromium, or even Titanium. I think the steel/iron engine block will be with us for awhile while ceramic engines, both repcirocating and Wankel types, develop in the labs. [ November 20, 2002, 01:45 PM: Message edited by: MolaKule ]
Originally posted by MolaKule: My question is: WHy stop there? Why not go to a 0W5 grade such as NEO Synthetic's Oils
Heck lets drop on down to some thinner oil then,,enough with that thick stuff [Smile] The Quad-0 or LTS 0000 synergynracing Actually I have been running the LTS 3/30 and found no oil pressure problems,,,,,,yet ! [ November 20, 2002, 02:56 PM: Message edited by: BOBISTHEOILGUY ]
That's right, just put that 4 cSt base oil in everything with FM's and AW's and run the heck out of it! Come to think of it, forget the base oil, just run it on the mixture of FM's and AW's. Just remember (and I'm somewhat serious here), today's additives may become tomorrows base oils.
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