.. after removing the old oil. on a 14 year old engine with 111kmi, would this be problematic? i.e., would old sludge residing in the engine's nooks and crannies be released and cause grief?

IMO you have two choices both equally good.
Both have been suggested in the other threads.
1. Run a treatment of Auto-Rx which will clean the crud out of the engine safely. Then switch to a Sythetic oil and normal oil changes. Don't use a harsh flush because it might damage the oil seals.
2. Switch to a synthetic out right and plan on doing a filter change at 2000 to 3000 miles and top off. Then run until 5,000 miles and change out the oil and filter. From then on do your normal 5K mile changes. The reason for the 2K to 3K filter change is to make sure it hasn't been over loaded with sludge from engine. Yes there will be sludge even if you do 3000 miles dino oil changes.
When I replaced my oil pan seal there was a lot of sludge coating the pan. I did 3,000 mile oil changes from the day the dealer delivered the car starting after the free 1000 mile break in oil change. The pan gasket was replaced around 250K miles.

The problem with synthetic oil is the cost vs dino, and the fact that it is best to replace it at approximately the same interval. I run synthetic in my Honda, and have selectively run synthetic in several cars that I have owned, mostly cars that I bought new and intended to keep until the wheels roll off. I have had fine service out of them, and peering into the top of the engine reveals little if any gum. I also have a 91 Chevy 5.7 Liter w/120K+ that has run dino exclusively and still runs like a top, and it looks very similar. The issue that I have is that no matter what you run, the oil gets dirty, and needs to be changed around every 3K for that reason, unless you have a bypass oil system (which is capable of removing the offending particles)and you replace the filter every 3K or so. In 3K the dino oil is not broken down thermally or otherwise, so it is just as effective as synthetic at that point. Going much past 3K on either will be running your engine with particles that will cause wear.

I think that most of the the gum on dino lubricated engines comes mostly from oil that is not changed frequently enough.

All that being said, I think the best option is dino changed every 3K. Inexpensive and effective.

I change my oil and filter at least once a month, regardless of mileage; I use whatever oil was on sale when I last stocked up.

I have followed this with my GM vehicles and am doing so with my 240.

IMHO the frequency of change is the most important factor in reliability.

--
__Stef -- 81 DL wagon B21A SU carb M46 314000km

My dad was a chemical engineer for Esso and he used synthetic, changed it at 5000 kilometres.

I think turbo motors in particular will last longer if synthetic oil is used. That way when your wife goes ripping down the highway on a hot day, pulls off for gas, doesn't let the turbo cool down, and simply shuts the car down...the synthetic oil will be able to withstand the scalding hot turbo.

Lots of people accuse dino oil of being more likely to cook inside a hot turbo leaving little crusties everywhere.

Peace of mind. It costs more because it's better.

I'm happy with non synthetic. Hell with the years and the mileage I get on all my vehicles (non Volvo's included), the bodies start to go long before the engine anyway.
My '89 Volvo is the newest vehicle I own.
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me

Tony,

You may be in for a pleasant surprise with your Volvo. I think you'll find that the body holds up much better than any of your other vehicles. Heck, I think Jeeps come pre-rusted from the factory! (check my signature)

I wouldn't consider running synthetic in a Chevy w/ 200K miles. But that's exactly what I do with my Volvo Turbo.

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

the flush is used to help remove the sludge/varnish/goop left in the engine after a diet of non-synthetic. If you don't, or won't, flush, then plan to change the filter and top off after a couple thousand miles. If you notice a sudden increase in oil consumption, change the filter and top off.
If you don't flush, you may want to drop the first batch of synthetic after 5,000 miles or so.

when AMSOIL introduced their flush many years back, they found that complaints about excessive oil consumption dropped about 75%.

Dick,

Why does a clogged filter increase oil consumption? Just curious.

Thanks.

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

Perhaps the filter fills with crap and goes into bypass mode, then the dirt gets into the clearances of parts that control oil, such as piston rings.
--
96 855R, 95 855,854, 90 744 Ti - 343,000 Volvo miles put on 7 bricks

As others said, just do it. If you want to go the extra mile and potentially realize some other benefits, use auto-rx prior. Auto-rx recommends using dino oil for the rinsing process.
--
Paul NW Indiana '89 740 Turbo 110,000

You should have no concern - a flush isn't necessary. Check out Bobistheoilguy.com I bought a brick with 250,000 miles and switched it too Mobil 15W50 - its a B280F though.

A synthetic will start cleaning some "crud" out of the engine - so you may not want too run an extended drain interval initially. If you're engine is normally aspirated I would have no concerns of going 6 months up too 10,000 miles with a true synthetic (Mobil 1, Amsoil full synthetic, Royal Purple etc). I'd be more concerned about the filter being used up before the a true synthetic breaking down.

If you are in a warmer climate and want something that will keep your engine clean any of the major brand 15W40 Diesel oils will work. Switch too a semi-synthetic 15W40 or a 5W40 (Shell, Mobil) diesel oil in winter for better pumpability.

I think a best buy is not a true synthetic, but its sold as a synthetic and is Shell Rotella T 5W40 (@ $13 per gallon at Wal-mart). I used it in my 740 Turbo. Another good buy is Ford Motorcraft 5W30 (or maybe 10W30) that is labeled as semi-synthetic and is only $1.42 a quart at Wal-mart...i may run it over the winter months and back away from the expensive true synthetics.

Worry, worry worry...
Just change the oil and filter; forget the flush, forget the horror stories.
If the engine needs new seals, it needs new seals with dino oil, too.
I, personally, have never changed over to synthetic on a car with as few as 111K on it, but even at 140-200K, I've never seen ANY problems.
--
Jim McDonald

Ditto-mundo! To what Mr. Mallard says.

Like Nike says: Just do it!

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

...so i was under the impression that the more slippery synthetic would reduce wear. i think amsoil says not to use synthetic during engine break in because the reduced metal to metal contact retards the break in process. i'm thinking this would be a good thing after break in.