oil grade

[TOPLINE]

just been offered a amount of fully synthic oil 5w-40 from FORD MOTOR CO is this grade ok to use in my hummer h2 over here in england as we dont have anywere like the cold weather you have over there

cheers shaun

[IRA51]

that should be ok,kinda parshal to Mobil 1 10/30 my self .

[nmu98]

I am not an oil guru, but i say hell no. If you use 5w30 or 10w30, My guess is that only in really cold starting could you wear anything more than normal....

You are upping the weight of the oil when its hot by going to the 40. These new engines are built with very tight tollerances and designed for a specific oil. most Fords now want 5w20 and caution the use of 5w30.

[IRA51]

i HAVE USED 10/40 IN MY 2000 Z28 with a 382 stroker motor motor (LS1) 450 hp at the rear wheels (11.86) in the 1/4 mile and street driver in Phoenix for 6 years with no problem 26000 miles and runs like a champ .

[nmu98]

Originally Posted by IRA51

i HAVE USED 10/40 IN MY 2000 Z28 with a 382 stroker motor motor (LS1) 450 hp at the rear wheels (11.86) in the 1/4 mile and street driver in Phoenix for 6 years with no problem 26000 miles and runs like a champ .

OK, but that is not a 6.0 in a Hummer, and has WAY more HP... You would want the higher wieght oil for less shear in that engine....

I am not saying I know right or wrong here... I am just sharing my idea.....

[mdoyle]

You guys can't compare various motors and grades of oil and draw any conclusions about performance. The viscosity oil is specified for a particular motor design and it's not necessarily about quality this or quality that.

The main key is this- bearing clearances and their L10 life are based upon the formation of a hydrodynamic wedge of oil between the running surfaces. The viscosity is specified for that clearance and a few other variables, but mainly that one clearance.

What happens with a sleeve bearing like the ones on the crankshaft, connecting rods, and camshaft is this: when a shaft turns inside a cylindrical bearing that is oil lubricated, instead of the oil flowing outward like you'd expect it pushes inward from both sides forming a pressure ridge in the middle. This wedge formation supports the shaft that's turning inside it.

Since the wedge isn't present at start-up, that is when most of your wear occurs. It's also the reason turbo equipped cars usually have a pressure reservoir to supply the turbo bearings after shut-down while the impeller is still spooling down.

Stick to the manufacturer's oil specs, avoid "snake oils" that make absurd claims, and use the right SAE ratings for your car and you'll do well.