5W-30 in summer?

Hi there,
This isn't anything super-important, but I was just curious-
I have a '78 Buick Regal with a 3.8 V6. I had the oil changed back in
January to (non-synthetic) Mobil 5W-30 because it starts better with
the 5W-30. Thanks to walking a lot and using public transportation, I
have only driven the old beast 900 miles since then. The old
Chilton's book says only to use it up to 80 F in my car, but someone
told me that was probably just because late-70s oil was not as good
technologically. Anyway, do I have to change my oil now, or should I
let it go the full 3000-5000 miles?

"Bill Johnston" > wrote in message
oups.com...
> Hi there,
> This isn't anything super-important, but I was just curious-
> I have a '78 Buick Regal with a 3.8 V6. I had the oil changed back in
> January to (non-synthetic) Mobil 5W-30 because it starts better with
> the 5W-30. Thanks to walking a lot and using public transportation, I
> have only driven the old beast 900 miles since then. The old
> Chilton's book says only to use it up to 80 F in my car, but someone
> told me that was probably just because late-70s oil was not as good
> technologically. Anyway, do I have to change my oil now, or should I
> let it go the full 3000-5000 miles?

As long as your engine isn't worn out and leaking/blowby you should be good.

"Bill Johnston" > wrote in message
oups.com...
> Hi there,
> This isn't anything super-important, but I was just curious-
> I have a '78 Buick Regal with a 3.8 V6. I had the oil changed back in
> January to (non-synthetic) Mobil 5W-30 because it starts better with
> the 5W-30. Thanks to walking a lot and using public transportation, I
> have only driven the old beast 900 miles since then. The old
> Chilton's book says only to use it up to 80 F in my car, but someone
> told me that was probably just because late-70s oil was not as good
> technologically. Anyway, do I have to change my oil now, or should I
> let it go the full 3000-5000 miles?

Some recommend not only a mileage interval but a time interval on
changes. You have to follow your conscience on this. I personally
feel you are good to go, but an oil change every six months is not a lot
to invest.