oil & oil filter

Hi everyone;

I have a 97 SL, 130000 km (81250 mi).
I have been having the oil changed every 5000 km (Castrol 5w/30w)
Last change I went for Mobil Synthetic. Noticed a smoother run (maybe
it is a subjective perception of mine).
Question 1: is it advisable to extend to 10000 km the interval of oil
changes with synthetic?
Question 2: from browsing this site, I learnt that Fram is a no-no in
oil filters. Everyone advises against.
So, for next change,which filter brand do you think would be better:
Quaker State?, Valvoline? or, the Fram Synthetic?
The price difference is not an issue, the life of the engine is.
Thanks in advance for all your comments and suggestions.

danielR.

 

I like Mobil 1 oil and PureOne Oil filters for my 3800 and I just change
my oil and filter every 4000 miles. I could go longer on the oil for
sure if I racked up more miles in a shorter amount of time to burn off
moisture and gas in the oil. I take 1+ hour trips when ever I can just
to burn out contaminants. As oil advances so do filters. If a filter
captures more dirt, it clogs up faster. Good filters shouldnt be of much
use after 4000 miles.

http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html

 

hi everyone;

Thank you very much for all your comments and suggestions.
Based on the folowing facts:
I live in Toronto, Canada, and operation under cool temperatures is an
important factor,
Most of the filter brands you mentioned in your replies are well
considered in a site dedicated to oil filters comparison :

http://minimopar.knizefamily.net/oilfilterstudy.html

,but in Toronto I only have access to Fram, Valvoline (designed by
Purolator people), and Quaker (Fram disguised under different name).

I will go for Valvoline.

Regarding the type of oil and frequency of changes:
I will remain with synthetic.
Now, at onset of Spring, will stretch the synthetic I have to 6400Km
(4K miles), but in Winter, I believe it will make more sense to change
every 3K miles (approx 5000Km).

Thank you all again.

danielR