99PTA

I waswondering if Mobil 1 15W-50 was thick of an oil on a basic bolt on Trans Am?

Steve - Race Eng

iTrader: (1)

Use a lighter weight. Clearances are tight on these engines - they are designed for 5w30. A 15w50 will take longer to thin out on cold start and get to critical areas of the engine resulting in greater wear. Gas mileage will suffer also from the increased rotating friction a higher viscosity oil.

Steve
Race Engine Development

Noyzee

iTrader: (37)

id use a 5-30 or st 30. unless you get a different pump.
i run 50 wiegt in my car

99PTA

A local oil place..... suggested mobil 1 10w-30. is that good or shoudl i just get 5-30

Assassin

iTrader: (3)

castrol GTX 20/50 here!

SSCamaro99_3

iTrader: (1)

I was running a mixture of Mobil 1 0W-40 and 15W-50. 4 parts to 2. Did the same substituting 10W-30 for the 0W-40. I am switching to Redline 10W-40.

PlainwhiteZ28

unless you have a powerstroke in your car, Id stick with 5w30 or 10w30

stealth

I use Mobil 1, 15W50.

antz01ta

iTrader: (3)

or a stroker motor that runs 2.5 - 3 thousandths bearing clearance.

stealth

I assumed one could tell from my sig that, since I am using Lunati, I was running ~.0028 to .0030 main bearing clearance. THey recommend .0030 out of the box.

Damian

iTrader: (89)

15w50 would be ok for a high mileage motor that see's a lot of abuse. IE: 90-100K+ miles. A buddy of mine runs 20w50 in his 98 motor w/ 125K on it, sprays it daily with no problems.

10w30 at the very least. 5w30 is way to thin IMO, that **** is almost like water before heating up...

I used 10w30 Valvoline in my 98 shortblock from day one, beat the living **** out of it for 40K miles, and upon teardown my internals looks almost brand new. Bearing wear was almost invisble...

ataylors

iTrader: (2)

It also has alot to do with what your climate is like. I have been running Mobil 1 15-50 in my Grand Prix GTP since 98 with no troubles

sickfive55

i use amsoil 0w30 is that bad? my car runs good...

jimmy 2 Times

iTrader: (18)

i was told that i should run 4.5 quarts of 5w30, and 1 quart of 15w50, what is the advantage of this?

Patman

15w50 is too thick, go with 0w40 instead. The LS1 likes a thick 30 to thin 40wt oil.

Glenn98ZM6

realize that M1 is on the thin side compaired to the same viscosity of Dino oil. i also run 15w-50 M1 in my car. and i have for well over a year or so. my car is used for road racing and spends lots of time above 5K (like 20 minutes straight). i use this wieght to fight the thinning of the oil due to temp (was 300 degrees + before the oil cooler). just be smart and let the car idle for a minute before you drive off.

Patman

If you see high oil temps, it's best to do what Glenn did and get an oil cooler, instead of running the thicker 15w50.

ssfiress

its all about 10w 40 amsoil.

blacktransam

iTrader: (13)

10w30 for break in then 10w40 redline for the rest of her life. remember adavanceautoparts stores now carry redline in stock.