B.Diggity

Anyone? Im strongly thinking next oil change to do so. I hear more n more lnf cobalts with high hp do. I might even stick with amsoil 15w40, but just curious if any of yall have yet.

donbrew

What is the reasoning? Modern cars need the 5 to get thru the tiny journals on cold starts, at least that's my understanding.

firemangeorge

Only use the 15w40 in my Kubota diesel tractor.

My SS gets the factory recommended stuff to keep the powertrain warranty intact.

IgottaWoody

5w is for below 32 deg starts...no reason for 40 wt unless your absolutely pounding on your eng and your running the risk of really high temperatures. Those cobalt guys are also probably running a lot of hard core mods .. and street racing... and still relying on old school text books...

Tyler Harvey

I agree, stick to the manual.

843de

Trust the engineers, stick with the recommended viscosity and your engine will thank you.

cornwalis

You run 15w40 youll cause more engine where on cold start the oil wont flow up fast enought or or flow downwerd you culd go 5w50 or 0w50. Royal purple makes an 0w50 if I remember right. Oils ghees days or multy viscosity. This when their cold as they heat up they get thicker. Too think is as bad also seen pple put too much lucas oil stabilizer in and blow a gasket. Valve cover blown. Oil flowing threw the valve cover vent into the intake thats a nice mess to clean

cornwalis

You run 15w40 youll cause more engine weare on cold start the oil wont flow up fast enought or or flow downwerd you culd go 5w50 or 0w50. Royal purple makes an 0w50 if I remember right. Oils ghees days or multy viscosity. This when their cold as they heat up they get thicker. Too think is as bad also seen pple put too much lucas oil stabilizer in and blow a gasket. Valve cover blown. Oil flowing threw the valve cover vent into the intake thats a nice mess to clean

jay loukakis

Where is Whopper? when we need him? out changeing his oil???

sleeper

Jay- (perfect timing)..