ZSU

My car leaks engine oil a bit much..
Should I use,
CASTROL MAGNATEC 5W-30 A1 or CASTROL MAGNATEC 10W-40 A3/B3

LS6427

iTrader: (2)

A leak, what leak?

Do you mean you "burn" oil?

beezer1519

iTrader: (19)

hmmmm i'm pretty sure if it's a leak it'll continue leaking regardless of visc... it won't be thick enough to slow a leak...

nemss1

^^^agreed

ZSU

I mean Engine Oil is leaking from Engine seals...

beezer1519

iTrader: (19)

yeah... not gonna work you will have to replace the seals... whichever ones it's leaking from... sorry

ZSU

Dino oil s molecules are bigger that synthetic oils.. so any change at leaking with that?

and by the way, u say nothing will change at leaking using 5W-30 A1 or 10W-40 A3/B3?
I were using 10W-40 cuz repairman said it will leak less... But GM refers use 5W-30... will it leak more if I use 5W-30??

ZSU

They said whole Engine must remove to change seals! Think about labor cost for me :/

beezer1519

iTrader: (19)

yeah, **** where is it leaking from??? and the difference in the numbers is the thickness of the oil... no matter how thick it is if it is bad enough to leak the oil will leak through... now the thicker oil which is the 10w-40 might 'slow' down your leak... not good enough i'm afraid but it might depending on what type of leak you have right now... droplets forming? drops actually dripping 1-2 every min??? or a constant drip??? like as soon as you stop 3-4 drops withing i'd say ten seconds???

ZSU

I am not sure but they said front and back.. and crank seal.. smth like that..

Not exactly but Engine oil leaks like 1 liter about 1 month.. when u stop you can see it like oil spit..

beezer1519

iTrader: (19)

well if you can wait off and save money you should get it fixed... that much oil isn't too much but it's not something to ignore... crank seal is a bitch because you have to remove the tranny the front shouldn't be too difficult but that's on an ls1 i assume by your avatar you have an lt1...

ZSU

yep I agree with you.. My tranny rebuilted 3 weeks ago.. I should say change it.. MY car is lt1 u are right so I should use 10-40..
thnk you

LS6427

iTrader: (2)

Try to put in an oil leak sealer and see if it helps. STP oil treatment is supposed to work on small leaks pretty good.

Why does tne engine have to come out to replace seals?

coolformula

iTrader: (21)

If its the front seal seveal you can replace just pulling the water pump.

1 FMF

iTrader: (1)

the molecules have nothing to do with it,,, the oil molecule is <<<<<<<< the size of the gap in the oil seal where it is leaking. The difference between 5w30 and 10w40, syn or conventional, has to do with the viscosity and at cold oil temps like 30F and below the 10w40 may not leak but only when the engine is off. Once the engine is running and the oil is 100F or hotter any viscosity oil is going to leak, only solution is to replace the seal.

what you also might want to check is the PCV system. If it is blocked the crankcase can build up pressure that will blow oil out the crankshaft seals, and possibly blow out the seal entirely and cause massive oil leak. Also do a compression test, if you have low compression that could mean blowby which can cause high pressure in the crankcase.