Oil weight does it matter?

[Rico]

I have a 2000 Chevy Silverado with at 5.3L engine.  The oil cap says to use 5w30 oil.  Currently I am using Castrol semi-synthetic 5w30.  But 5w30 is not always available, is it ok to use 10w30 Castrol semi-synthetic instead? The 10w30 Castrol is always available. I live in a pretty warm climate (Texas).

[Shaners]

I run what is recommended by GM.  GM says that if temps stay above 0*F, then 10W30 is fine for your truck.

[silversport]

Yup...for us in the colder climes...5W30...5W30 Mobil1 here!          :hail:

[americanmuscleman]

Rico, your fine to run 10W-30.

[99silveradoz71]

I can relate, mobil 1 in 5-30 is a little harder to come by up here in Cleveland, but I end up finding it and with our winters, it's 5-30 for Blue.

[SilveradoWV]

I always run 5w30 Castrol GTX in my truck because it is very available. I dont see any harm in running 10w30 above 0 degrees though!

[Stepside Z]

I ran Mobile 1 5-30 with no problems. I would do it again if I ever go back to gas.

[dukbludvl]

I run 5W-30 in the winter and 10W-30 in the summer here in NC.  Haven't had any problems switching yet with 50K miles. Does anyone see a problem with this?

[CapnDean]

Nah...  the first number gives you flowability when cold and that's the important thing when you get really cold.

 

Honestly I doubt it would make much difference short term (suppose you had 10W-30 in it and the temp was -20).  But if you lived in the Yukon and it was always that cold over time the lack of good lube when you started your engine would be not so good.

 

That being said:  And anyone who has ever attached an electric drill to a dismantled distributor that spins the oil pump while your freshly built 400 chevy motor gets ready for it's first start....{pre-oiling}  I submit the following question:

 

Why isn't electric pre-oiling standard on all IC engines?

Could it be...planned obsolescence?  

 

It is common knowledge that the MAJORITY of engine wear occurs at startup....

[maggot]

I have a question.

What runs the oil pump on the Gen III's?

[Black02Silverado]

I run 5W-30 in the winter and 10W-30 in the summer here in NC.  Haven't had any problems switching yet with 50K miles. Does anyone see a problem with this?

10w-30 is fine. One of the other reason's for GM and others manufacture's suggesting 5w-30 and like Honda now saying to use the 5w-20 is for fuel economy. They are able to meet government needs and squeak out what they can to get better mileage.

 

No problems at all in switching from one grade to the other in the summer and winter.

 

[chvythndr]

I use Pennzoil 5W-30 in my Z and I'd prolly change to Mobil 1, but if it's not broke, why fix it.  I run Mobil 1 in my bike and that stuff is unbelievable.  I did however change from a Fram filter on my truck to a Mobil 1 oil filter b/c I hear fram blows...

[points]

I run 5W-30 in the winter and 10W-30 in the summer here in MN.  I burn a little 5W-30 but in the -20s here, i need 5W.

[2001 HD]

Maggot-The Gen III oil pump is driven off of the front of the crankshft behind timimg gear. :thumb: