My philosophy is...run good oil and change frequently.
I don't think the flush would be needed unless there is a build-up of varnish present. As for the higher operating temps causing increased deposits that is a bit of an overstatement, IMO.
The oil technology has been staying ahead of the curve, and oils don't leave the nasty coating of varnish like they used to. They have been designed for the envoronment that todays engines create.
The majority of the oils out there now use a synthetic base. This and there own special mix of additives leads to a better, longer lasting and cleaner oil.
If you tend to run cheaper oil and run it a long time in terrible operating conditions, then a flush now and then would be a good thing.
The particulate matter in the oil (dirt) is what does the most damage, use a quality filter.
I have not been using the "Full" synthetics, but I can understand how they could perform well at extended change intervals. I would still change the filter at the normal intervals, for the given conditions.
If you want an example My HenryJ runs 200-230 degrees on the street. Even though it runs an external engine oil cooler and 8 gal. cooling system. It hits 7200 rpm at times
and I'm running Castrol 20-50w, which is a natural base oil. I have torn the engine down and rebuilt it 4 times in the last 12 years (the first three it was bracket raced every weekend) No build up , very little wear.
On the other side of the coin, we have some people who run the company rigs VERY hard in the worst conditions. When the oil starts getting pretty black between oil changes, I do use some SeaFoam to break the varnish. I run Delo 400 15-40w in the fleet, and have never had an engine failure due to engine oil :fingers crossed:
I believe that the DELO 400 uses a synthetic base.
I run Mobil 1 & it doesn't get black in 3K miles how can there be a build up to wash away unless we are geting some crystallization on the underside of the pistons.
