best engine oil

[tonttu]

my car is firebird 3.1 v6 and mileage is about 112500miles (180.000km) and i was thinking that what would be best engine oil for my car.maybe mineral,semi-or fully synthetic motor oil??when i bought the car about 2years ago i think that the first owner was using shell semi-synthetic motor oil but im not sure.and the oil was black and look like old oil so i changed the oil ac delco 15w40 mineral oil but later on when i was driving couple months and about 3000miles i changed that oil again ac delco 15w40 mineral oil.and after the oil change i stated the engine and i heard knocking noise coming from the engine. oil pressure was normal like always but the knocking noise was my problem and when i drove about 2000miles the knocking noise went almost away but was still knocking little bit.so i was thinking that maybe the 15w40 oil is too thick or something for the engine.so after that i changed the oil 76 10w40 mineral oil and it was little bit better than the 15w40 but it was still knocking and after that i changed the oil gm 10w30 mineral oil and now the knocking noise is almoust went away and now i hardly even hear the knocking noise anymore.now i have 5w30 mineral oil in the engine but im gonna change it back 10w30 after winter.but now the engine is leaking little oil. it leaking somewhere in the bottom of the engine maybe somewhere around the start motor.but im gonna change the sealings where its leaking next summer.and i think it has been leaking oil since i got that car but now little bit more.maybe the 5w30 or 10w30 oil is too thin oil for the gasket and sealings to hold.and i was wondering after i fix the leaking spot,if there any change that it starts leak again if i use the 10w30 or 5w30 oil in the future?and now the oil pressure is littlebit lower than it use to be but i think its because it leaking little oil.so if anyone could help me with this problem i would very happy.thanks [img]smile.gif[/img]

[V8 Killer]

Regular 5W-30

[Camaro Dom]

mobil 1 5w-30 and maybe a lil of that lucas oil stabilizer... never heard anything bad about anything made by lucas so i'd say you pretty good given ur engines age...

[cam98aro]

Originally posted by V8 Killer:
Regular 5W-30

Pennzoil 5W-30 for the win

[tonttu]

should i use semisynthetic fyllysynthetic or mineral oil?

[98Camaro3.8]

Originally posted by tonttu:
should i use semisynthetic fyllysynthetic or mineral oil?

Stick with plain 'ole dino oil. Switching to synthetic with that many miles will result in leaks.

[Camaro Dom]

meh, if you want my honest to god opinion... really oil is oil. like, i mean, different oils do different things, but when it comes down to it, the differences are pretty insignificant. so unless you're building a racing motor where those little differences are important, dont even bother worrying about it. tho like 98camaro3.8 said, a straight synth will likely give ya leaks, so buy a hi-milage synth. if ur gonna go that route. seriously, when it comes to oil, the most important thing, far and away, is that you change it, not what kind it is. buy a hi-milage synth or dino oil. just choose a good trusted 5w-30 brand oil and change it every 3,000 and you'll be fine.

[tonttu]

if there any risk if someone start using full or semisynthetic oil that engine could broke down?i have heard stories that if you have been using mineral oil and then start to use full or semisynthetic oil all the bossible dirt or slugde in the engine start to going around to the oil channels or oil filter and blocked those places?is that true? [img]graemlins/omg.gif[/img]

[Den69RS96]

I put a ton of miles on all my cars, so I switched over to Royal Purple. I know most people are not willing to spend the extra $$ for the oil and I don't blame them. The reason I swithced was for the extended drain intervals for my wife's car and my commuter car and the fact that it I can keep it in my camaros longer(which don't get driven regularly). Reg oil needs to be changed every 3000, but RP can go up to 10000-12000 miles with a regular filter changes every 3-5000 miles. I put on 3000 miles on my commuter every month and I got tired of changing oil on two cars every month. Been using RP for a year now and I'm very happy with it. All my cars run smoother with it and I picked up almost 2 miles per gallon. In my situation, the oil pays for itself and frees up time for me.

I asked the engine builders at the local speed shop if RP was worth the hype. They all said that when they tore down the engines at the end of the season that used RP, the bearings looked brand new.

High quality synthetic oils help clean you engine and remove deposits left behind. Sometimes the deposits left behind block existing leaking seals so when the synthetic removes these deposits your bad seals will leak.

[Camaro Dom]

i dunno man, i trust a 10k mile oil change as much as i trust my ex-gf... but thats not based on anything but my gut and my habit of a change every 3000

[ezrollin]

Originally posted by Camaro Dom:
mobil 1 5w-30 and maybe a lil of that lucas oil stabilizer... never heard anything bad about anything made by lucas so i'd say you pretty good given ur engines age...

incorrect, Lucas oil stabilizer is bad for gears.
since its petroleum based, it creates oxidation (air bubbles) which heats it up.

I'm switching to Mobil1 5-30 extended performance.
"""Proven protection for up to 15k miles, guaranteeed"""""""""
which is good, for when i get my turbo

[Camaro Dom]

Originally posted by ezrollin:

incorrect, Lucas oil stabilizer is bad for gears.
since its petroleum based, it creates oxidation (air bubbles) which heats it up.

I'm switching to Mobil1 5-30 extended performance.
"""Proven protection for up to 15k miles, guaranteeed"""""""""
which is good, for when i get my turbo [/QUOTE]

huh? petroleum based? arent ALL oils petroleum based? who told you it was bad? i've heard nothing but good things about it from everyone i've talked to.

[ezrollin]

http://www.bobistheoilguy.com/images/lucas/lucas.htm

yes, most oils are petroleum based
mobil 1 fully syn doesnt have petro

[tonttu]

i was looking those oils over the internet and there is term synthetic blend.does that mean that 5w30 and 10w30 are semisynthetic or fullysynthetic oils?