I'd rather have a little old oil in there than a little flush left in there. I don't see a trace of sludge in my engine though so I don't know what I would even try to flush out.
I don't really go for the flush idea, and as any normal current synthetic is fully compatible with dino stuff, it isn't required.
That said, on some engines that have been sitting for a very long time or are sludged up a bit, I have run them with some ATF (lotsa detergents apparently) in there getting them up to temp, but no engine loading, and drained it hot. Seems to help remove some of the sludge/stuck rings, etc. Your call.
if you want to flush it,,,,dump the oil+filter,and on the refill"flush",use dino oil,with 1 quart of marvelmysteryoil,,,dothis,and run it for a few days,,like 200 miles or so,,dump it and fill w/synth if you want,,dosome research on marvel,,its a naptha based oil,,about 10w,,its a "cleaning oil" basically,,good stuff!!swear by it,not at it,,,,,most of the time,if i knew an oil change was coming up,next week or somethin,,and i was low on oil,,id dump some marvel to top it off,,,,is says use it in fuel too,,probably add some lube to the crappy diesel we got nowadays,,, :roll:
i've seen marvel mystery oil... maybe I'll have to try it sometime!
If you've got 470,000 (kms or gasp...miles?) using conventional oil...why mess with a good thing?
Why do you want to switch? I wouldn't bother but if I was going to I would get it really hot and than drain it asap.
I rebuilt the engine at 400k miles. I used mostly dyno oil untill recently when I studied more about synthetics (and had more money to buy it with). I do like how it starts and warms up with synthetic oil better than cheap walmart 15W-40.
maybe I'll sell my quantum and get a new jetta. my parents just got an 04. MAN is it nice!!! Powerful, quiet, plenty of useable space. just debating between the jetta or the passat.
I wanted to switch for better starts in the winter. Also, it is running great and I figured it would last longer with the synth. ...And it has 466km, not miles.
I have another engine with 80Km on it ready to drop in, but I want to see how long this one will go for.
$$$ for new jetta's. You'll love your ride, but miss that extra cash you had, and won't be able to do much if any work on your vehicle yourself
oh yea for warranty you'll need to take your car to a garage for oilchanges and keep receipts. Man new cars are a real hassle
one thing I notice with synthetics, is the power. I don't know if its the placebo or what... but there is a difference! Winter starts were always easier with synthetic too. I think it has to do with the fact that it has a much higher TBN than conventional oils, and stays viscous, but runny at the same time, so it can outlast most motor oils. (notice how your mileage/power decrease the closer you are to your oilchange??? not with synthetic oil!)
I forgot to ask previously,
Should I have an engine flush done before I change the oil?
I would do an AutoRx treatment. I have used it in all my vehicles. It brought down the wear metals in my oil analysis after I ran it through my 5.3L in my truck. It cleans the engine slowly over time and is safe to use. Your engine didn't get dirty over night so what good is a five minute engine flush? If you want to read up more on it go to bobistheoilguy.com
http://www.auto-rx.com/