I was changing oil today on my silverado. After draining the old oil and putting a new filter on I added the 1st quart and noticed it was 5w-20w and not 5-30w. I drained the quart and pulled the new filter off. Chevy is very specific in their user manual about not using any other weight than 5w-30w. My question is: Do I need to do anything else after draining the 5w-20w oil out? Can I just put a new filter on and add 6 qts of 5w-30w without harming the engine? I use Mobile One Synthetic.

Thanks for your help
Allan

 

Welcome to the forum. Worried about a single quart of 5W20, Mobil 1 full synthetic at that? I would've just topped off with 5W30 and gone on with life. The viscosity of oil at operating temperature changes over its life, usually thickens first and then thin out (or was it the other way around?), anyway. At this point, just put the filter back on (was empty, wasn't it?) and put oil in.

 

I wouldt worry about 1 qt, it's fine.
and after you put some miles on it, it would be a good idea
to go with a heavier weight like 10/40 which is what I use.
And if it gets around freezing where you live it may be a
good idea to use a slightly lighter weight during the winter.

 

If you are using synthetic, I would not worry about it at all. I run 5w30 Mobil-1 synthetic in my Silverado, but I am certain it would still run fine on 10w30 or even 10w40.

I suppose it depends upon your driving habits and the climate in which you live. Top it off and get down the road, sir.

P.S. The 5.3L has the oil filter in the easiest location possible for removal and replacement -- vertically, right next to the pan!

 

I always fill the filter with oil before installing, helps the pressure come up quicker.

 

If you use the mobil 1 with the gold top you can also stretch out the oil changes. I do 10,000 miles. the last truck I had had 200k and if you look in the valve cover with flashlight it looks like brand new shinny aluminum. It was not dingy and brown like if you use pensoil or the oil from the gas station that just says oil.

 

Very smart move, always fill the filter prior to spinning it on this keeps the engine from being starved of oil while the filter would be filling with oil...

as to the mixed weight.. I too agree its not an issue if only one quart of the same brand and type but different weight is mixed.