is 10/40 oil ok to use in the fd?
12-27-03, 08:11 AM
#1
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is 10/40 oil ok to use in the fd?
Well even if its not ive been using it with good results so far.So heres the deal.During the summer I was using 5/30 and 10/30 oil.But it was just too thin.The engine ate like half a quart a week and it ran way hotter than I remember it running.I talked to a friend of mine who happens to know a lot about cars.He suggested i get thicker oil.He said it would stand up to the heat better.Especially when he saw how hot the rotary gets.He said in theory that the thicker oil should last longer and should also cool the engine better.So I bought a quart of 10/40 synthetic and put it in.The car runs better,stays cooler,and ive checked my dipstick numerous times to see if the engines been eating up oil and the dipstick barely changes.I already know about the oil injection into the combustion chamber and that its perfectly normal.My question is this.Im not running full 10/40.More like a mix of 5/30 and 10/40.Im coming up on an oil change and I wonder if running full 10/40 will change the results of my findings and also if it will be detrimental to my engine.
12-27-03, 10:31 AM
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hmm.well ive tried to use 10/30 already with somewhat questionable results.What additives are in 10/40 thats bad for the rotary? Basically what does it do to the engine thats bad? you also mentioned 10/50.So I take it that 10/50 is thicker than 10/40 and no harmfull additives? if thats true then 10/50 is for me.The thicker the more protection for my baby.And the cooler it will probably stay.Right?
12-27-03, 10:46 AM
#4
Originally posted by maxcooper
Conventional (mineral) 10W-40 oils have more viscosity enhancers in them, and this has given them the reputation of not performing as well as other weights. No car manufacturer that I know of recommends this weight for any of their new cars, which might also be an indication that it isn't good oil. As with most information available about oils, this is more of a rumor than a substantiated fact.
-Max
Conventional (mineral) 10W-40 oils have more viscosity enhancers in them, and this has given them the reputation of not performing as well as other weights. No car manufacturer that I know of recommends this weight for any of their new cars, which might also be an indication that it isn't good oil. As with most information available about oils, this is more of a rumor than a substantiated fact.
-Max
12-27-03, 11:02 AM
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I normally run 20w50 Castrol dino juice during the hot seasons, and during the cold, run 10w40 dino. I have recently switched to 15W50 synthetic since I removed my OMP.
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12-27-03, 02:19 PM
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I read and see that it says it has harmful additives... but why would it be worse than 20/50 or 10/30 dont they have the same additives? I thought the only difference was in weighting and viscosity?
12-27-03, 02:23 PM
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Originally posted by XSTransAm
but why would it be worse than 20/50 or 10/30 dont they have the same additives?
but why would it be worse than 20/50 or 10/30 dont they have the same additives?
Originally posted by XSTransAm
I thought the only difference was in weighting and viscosity?
I thought the only difference was in weighting and viscosity?
12-27-03, 02:29 PM
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so im not supposed to run 10/40 because it has some special additive that all the other weights dont? does anyone have any information what this additive is or why it shouldent be used? does it eat seals or bearings or something?
12-27-03, 02:45 PM
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For what ist worth,I have been using Pennzoil 10-40 for over 20 years in all ( except my 8) of my trucks, cars and motorcycles and have never had an engine(rotary or piston) failure.
12-27-03, 02:57 PM
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Originally posted by XSTransAm
this is why im asking, i see ALOT of misinformation on these forums and I want to see if anyone has any real facts to back it up or if its just hearsay
this is why im asking, i see ALOT of misinformation on these forums and I want to see if anyone has any real facts to back it up or if its just hearsay
http://www.vtr.org/maintain/oil-overview.html
Quoted directly from the site.
Multi viscosity oils are one of the great improvements in oils, but they should be chosen wisely. Always use a multi grade with the narrowest span of viscosity that is appropriate for the temperatures you are going to encounter. In the winter base your decision on the lowest temperature you will encounter, in the summer, the highest temperature you expect. The polymers can shear and burn forming deposits that can cause ring sticking and other problems. 10W-40 and 5W-30 require a lot of polymers (synthetics excluded) to achieve that range. This has caused problems in diesel engines, but fewer polymers are better for all engines. The wide viscosity range oils, in general, are more prone to viscosity and thermal breakdown due to the high polymer content. It is the oil that lubricates, not the additives. Oils that can do their job with the fewest additives are the best.
Very few manufactures recommend 10W-40 any more, and some threaten to void warranties if it is used. It was not included in this article for that reason. 20W-50 is the same 30 point spread, but because it starts with a heavier base it requires less viscosity index improvers (polymers) to do the job. AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30. Mobil 1 uses no viscosity improvers in their 5W-30, and I assume the new 10W-30. Follow your manufacturer's recommendations as to which weights are appropriate for your vehicle.
Very few manufactures recommend 10W-40 any more, and some threaten to void warranties if it is used. It was not included in this article for that reason. 20W-50 is the same 30 point spread, but because it starts with a heavier base it requires less viscosity index improvers (polymers) to do the job. AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30. Mobil 1 uses no viscosity improvers in their 5W-30, and I assume the new 10W-30. Follow your manufacturer's recommendations as to which weights are appropriate for your vehicle.
12-27-03, 04:13 PM
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Originally posted by XSTransAm
this is why im asking, i see ALOT of misinformation on these forums and I want to see if anyone has any real facts to back it up or if its just hearsay
this is why im asking, i see ALOT of misinformation on these forums and I want to see if anyone has any real facts to back it up or if its just hearsay
12-27-03, 06:43 PM
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For a start, it's considered a bad idea to use any kind of synthetic oil in a rotary. IMO you should be using a mineral based oil. Any of you that say you shouldn't use 10w-40 because of the additives should check the kind of crap used in synthetic that won't fully combust, leaving lots of ***** in your housings.
I recommend Castrol GTX 10w-40 (Don't think Castrol make the 10w-30 anymore!)
But hey, what would I know :P
I recommend Castrol GTX 10w-40 (Don't think Castrol make the 10w-30 anymore!)
But hey, what would I know :P
12-29-03, 07:45 AM
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Well while we are on the subject how about straight 30 weight in the summer? I am guessing it would have no additives at all since it doesn't need to morph or whatever the 10wXX does.
12-29-03, 10:04 AM
#23
Eats, Sleeps, Dreams Rotary
maybe the discussion of the additives maybe a myth??
not sure...
but my BMW M3 uses 10-60 (yes it is a real weight and only castrol makes it and cost $8-9 aquart!!) and the oil change recommended by BMW is around every 15000 miles!
not sure...
but my BMW M3 uses 10-60 (yes it is a real weight and only castrol makes it and cost $8-9 aquart!!) and the oil change recommended by BMW is around every 15000 miles!
12-29-03, 10:11 AM
#24
Ex fd *****
Mazda's ONLY recomended Oils for the FD are 10-30, for most regions, and 5-30 for climates w/Average temps BELOW 32degF (0c) they do not recomend anything heavier than 10-30 for any climate range - I run Castrol GTX 10-30.
12-29-03, 10:18 AM
#25
Eats, Sleeps, Dreams Rotary
here is a group of people studying Mobil1 (on the same site they are currently comparing Mobil1 vs. Amsoil)
http://neptune.spacebears.com/cars/stories/mobil1.html
the interesting thing about the analysis of the data and oil is that they concluded 8-15000 miles between changes and that "topping off" the oil and changing the filter was just as good and that changes every 3000 miles actually caused MORE wear on the engine...
http://neptune.spacebears.com/cars/stories/mobil1.html
the interesting thing about the analysis of the data and oil is that they concluded 8-15000 miles between changes and that "topping off" the oil and changing the filter was just as good and that changes every 3000 miles actually caused MORE wear on the engine...