different oil weights

[brian89gp]

Some say that 5w30 is used for emissions purposes, some say it is necessary. Then I hear about others using 10w40 and 15w50 because it makes the engine last longer. Whats everyones general opinion on this?

[Anonymous]

I use all Mobil 1, 5w30 in the winter and 10w30 in the summer.

[93LuminaZ34va]

I've used Valvoline Racing 10w30 all year around and a qt. of Lucas Oil Treatment in mine every oil change since 49,000 miles and I've ran the dog doo outta the thing, now has 106,000 miles on it, doesn't burn a lick of oil, knock, nothing. My dad ran the same in his Camaro since 10,000 miles.... now has 230,000 miles on a 305 V8..... VERY uncommon for a 305 to survive that long in a Z28 with someone with a heavy foot.... heads have never been off, we did finally get a tapping lifter at 200,000 miles that we had to replace..... but thats IT. Ever since he started putting it in his Camaro..... thats what we've stuck too. If I were to rebuild or get a newer car, i'd switch to full synthetic. Brian89GP..... with your turbo, just make sure you get a Turbo spec oil (Valvoline 10w30 Racing is)

[brian89gp]

I use Mobil 1 5w30, and i got at least 2-3 oil changes of the stuff sitting around. I've found receipts and for the majority of my cars live it has gotten Mobil 1, from 3k to now (110k) now minus 10-15k.

I was just curious if there was any benifit to running thicker oil. Seems that the factory oil keeps getting thinner and thinner, I heard the new Tbird uses 0w20.

[93LuminaZ34va]

I don't know about the new Tbird... but the new Chrysler Crossfire does use 0w40 full synthetic Mobil one from the factory. Alot of Mazda's use 5w20...... other than that and a few of the FWD V6 cars, they use the 5w30..... the rest here still use 10w30, recomending 5w30 for economy. I'd personaly stay with 10w30..... I don't like to use anything thinner, epsecially for anything that I'd use for ANY kind of Performance. In fact, for pure performance, i'd go with a straight weight oil, like straight 30 weight Valvoline Racing.... less fluctuations in Oil pressure vs. temperature, from what I've seen... doesn't necessarily mean thats the way it IS lol

[Anonymous]

I have run synthetic since my rebuild, now has 4k miles on it, and I will have Mobil 1 in it until I blow it again.

[Anonymous]

I use Pennzoil 5w30, still doing good at 192k miles.

[Homer]

0w20 synthetic is eqivulent to 5w20 non-synthetic or atleast according to mobil. Most fords take 5w20.

[4spdz34]

the reason they are going to 0w oils is cause the bearing tolerances are alot tighter and it gives better gas mileage, i used to run whatever in my old motor. 20-50,15-40, 10-40,10-30,5-30. some synthetic some non when its cold out i run the lighter oils, but i usally just look for whats on sale as long as its a brand name. but my new motor is gunna get mobil 1 5w30 after 500 miles and thats all its gunna get

[fathead45]

i use valvoline 10-w30 synth blend and mobil 1 filter. works fine for summer but i have to get it out for the colder weather. it seems to start alittle harder. i need to run some of the lucas treatment too.

[Anonymous]

I use Castrol GTX 10w30 and beat on my engine hard, with 273,5xxkm on the clock. If I were driving my GP right now (its parked in the garage for now) I'd put in the 5w30 for the winter that I have lying around in the garage.

Does anyone know if a COLD engine will heat up faster with 5w30 vs 10w30??

[3.4Z24]

i wouldn't break a fresh engine in on fully synthetic. it hinders the rings seating and on non roller pushrod motors(moot here) the cam won't seat correctly to the lifters. a while back, gm had some service announcements about the ls1 in the vettes not seating the rings correctly because they come from the factory with fully synthetic oil. i'm not sure what they're doing with them now.

after break in i run fully synthetic oil in the manufacturers spec weight if they origionally built the engine or if it's a stock rebuild. if i build an engine to different tolerences, i'll change the weight to match.

manufacturers are going to thinner oils because their manufacturing tolerences are better and they can run slightly tighter clearances. plus seal technology has come a long way and they don't leak with the lighter weight oils. i remember when synthetics first came out and people hated them because they 'caused' the engines to leak so bad-plus they didn't have the engineering or additives they do now and would wipe out bearings fairly quickly. my older brother still hates the stuff(old dog, new tricks? )

[SappySE107]

I read an article on the corvette ring seating procedure since it was an issue. Every tank of gas, run it up to red line in 1st and then let it decel in gear back to normal speed.

I was using 5W30 synth in the cutty, and it would go through a quart of oil every time I needed gas. I dunno what the deal was exactly, but I replaced the PCV and used some 10W30 mobil and its running awesome and no oil usage. Id guess it was the PCV causing the problems but I am having no issues with the thicker oil either. Once i get it running again, I will probably use 10W30 synth. I have no idea how the tolerances are in the engine since nico had it rebuilt. I pray the bottom end was done by a pro and not nico.

[pocket-rocket]

My mom's bf has a Kia he got brand new. When he mentioned that he wanted to run sythetic in it, they told him to go for about 5-10 miles with regular oil to let the engine break in properly.

EDIT, meant to say 5-10 K miles, lol.

[Anonymous]

I primed the motor and broke it in on Castrol 5w30, but after the break in I went to synthetic.