OK-no-I have not changed over to Amsoil--yet---running dino oil--in fact--Castrol 20-50W--been using Castrol 'forever'--regular changes-every 3000-inc filter--150k on '89 240 wagon---engine is smooth-relatively tight for 150k--no leaks -no burning oil--here is my latest "concern""-->Saw a post in the BB--somone started using Amsoil in their brick---engine began sounding "clattery"--loose--after change to Amsoil--wasn't that way with dino oil--somone questioned "What viscosity was being used before change to Amsoil??"--So thus my concern-->should I stick to same viscosity I have been using -or go ahead and use the "0-30W" Amsoil that I hear is so great?? *sigh*! Thank you everyone.

Go to Paul's website and link to the Amsoil page. Read about the technical advantages of synthetics and Amsoil and which viscosity to choose. Then go ahead and search the web for other info on Amsoil and synthetics. Draw your own conclusions based on a reasonably broad and fair look at the subject.

Unless you live in a REALLY cold climate, you do not need an oil with a 0W rating.

BTW, Fram filters have been known to collapse internally and destroy the motor. They are amongst the worst filters you can get.
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'84 "285" rice-eater with lotsa hp & performance goodies

Please refer me to this post. (link?) I did read the post about someone that switched to Mobil 1 and the valves were noisier.

Why, oh, why were you using Castrol dino 20W-50? 150K is real nothing major for a NA Volvo. I have 230K+ miles on the 85 245Ti. But if you want your car to really last you should at least use the viscosity as recommended by Volvo....I mean a synthetic 20W-50 typically has a low enough viscosity to pump fast and early...but a dino oil 20W-50 even in mild climates, just takes TOO long to pump and lubricate. Also the 20W-50 clings to parts longer is pretty much a myth, too.

If I were you and wanted to switch, indeed I would worry about the leaks starting -I can almost guaranty that even a 3000 mile change intervals there is crud in your engine and crud wearing at your seals and to some extent slowing/stoping leaks. I would do a good flush. And the first batch of Synthetic oil should only go 3-4000 miles.

As to what weight: 10W-30.
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http://www.fidalgo.net/~brook4/oilslubesfilters.html

Thanks for your input--I have been using 20-50W for years-doesn't mean I was "right" in doing so--you reccomend 10-30w--other reply says 5-30 or 0-30. Also you said I should flush and hinted I may get leaks--*sigh*--I hate leaks--as far as using 20-50w--I really am not sure how I started doing that--since the oil is supposedly at 20w when cold, I assume that "light" weight part would begin lubricating quickly-and viscosity would reach heavier weights only as engine heated up. At this point, I am just going to have to "take a chance"-maybe flip a coin as to what weight Amsoil to go with when I make the change-next part is to find best price--looks like around $8 a quart--give or take a few cents--is what I have to expect to pay. I usually buy either the higher end filters of Fram or Purolator---Volvo--heard there are better--some filter is supposed to filter out one micron--any suggestions on that? Any advice on synthetic oil additives?
btw-Thanks to the Bricksters-I found my flame trap--was really easy to change on my '89--right on top towards the back of the engine--about a 2 minute job--it was actually relatively clean in spite of using "dino" oil---but I had the new one in my hand-so what the heck--(the Volvo parts place I use regularly gave it to me at no charge.) May the "Great Volvo God" be with us all!

Regarding cost of synthetic oil , I always get a five quart jug of Mobil One or ocasionally Valvoline Syntetic from Walmart for about $18.00.The Mobil One comes in 5W30,10W30 and 15W50 weigth.I too was on a quest to get "the best" for my bricks but Mobil One does the job superbly in my turbo cars.Costco also has cases of Mobil one,six quarts each for about $22.00 in case there are no Waltmarts around.Regarding Mann filters one can get them on line in trays of ten for about $40.00 shipped.Just search for them.I buy them locally for about $29.00 a tray.Another great oil filter and a bit cheaper is Mahle.Made by the same people who make the pistons and rings Volvo puts in their motors.The Mahle filters are made in Austria.Excellent quality.Unfortunately my parts guy can not always get them .I would not use any kind of motor flush.Let the new oil do it.The first couple of oil changes the oil will be very dark.I ocasionally see Exonn fully synthetic oil for about $3.00 a quart.Just shop around.Now if one goes racing that might justify going for more expensive oils although a lot of local racing mechanics I know use Mobil One or Castrol Synthec with excellent results.
Good luck.George

0W, 5W, 10W will all work. Unless you live in Alaska, or so synthetic 10W is fine for a car that has lived on 20W. Put a jug of dino 20W-50 in the freezer. You don't want to know that it isn't pumping in your engine when not too much below freezing.

You very well may not get a leak...I just wanted to warn you not to blame the synthetic for causing the leak. If a car leaks right after changing to any other oil- I can gauranty that car already had a leak - you just didn't know it.

Amsoil 10W-30 is $5.70 a quart.

Top line Purolators are just OK. Fram is bottom of the line regardless the marketing name. Nothing wrong with Volvo OEM filters made by Mann. Amsoil, Mobil 1 and K&N oil filters are top of the line, but again you pay more.

A regular full flow filter will not filter 1 um particles. A bypass filter will.

It's a great sign that your flame trap is clean - how long have you had the car? Either the oil was changed very regularly or it was serviced not too long ago. In fact if it wasn't crusty there is some correlation that your seals may be in good shape AND have not be subject to undue crankcase pressure.
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http://www.fidalgo.net/~brook4/oilslubesfilters.html

The flame trap was not 100% clean-it had some "sludge" on it--all the holes were well open--the previous 2 owners (I am the 3rd owner)-kept the car well maintained-(They both kept meticulous records which I have now). The person I bought it from had it for 5 years-he was actually a "fanatic" (maybe even eccentric?) about fixing it up--replaced things that weren't broken--he just felt it had been long enough and certain things should be replaced--like the water pump-radiator--alternator-entire front suspension- changed the timing belt twice in 5 years--etc--he kept ALL his records--which I went over--the Volvo dealership knew him well--I saw personally over $18,000 in receipts of maintenance, repairs from his local Volvo dealership- (most "repairs and replacements" he did were NOT from being "broken"--he just did them--he gots lotta $$$$--said it was his "hobby"--buy a used brick--drive it for 5 years while basically restoring it-sell it at a loss--but he did get to drive it those 5 years---) his motto seemed to be --"If it ain't broke--replace it anyway". Oh-we have had it about 8 months now-I installed IPd's anti-sway bars--overload rear springs, and the 2 top "chassis-tower" braces--I am also looking for the "tower to tower" brace--(used)--(Our brick is a 240 wagon)-Bilstein HD rear shocks--the previous owner also put in new front struts about 2 years ago-along with the entire front suspenison being re-done. He even had the rear hatch removed--completely rewired and new tail gate shocks. (Ain't it fun to "brag" a little? Heh!) OK-the Amsoil--$5.70 a quart is good--I'll take 5 quarts 10-30, -and a filter! Thanks.

Read the FAQ on oil and lubrication. 20-50 is too heavy, costing fuel economy and engine thermal transfer capability. The optimal oil is one with very quick startup lubrication and sufficient film strength for normal operation. Amsoil 0W-30 is an IDEAL choice, as is Mobil 0W-30. A close second is 5W-30.

Read the FAQ on oil and lubrication. 20-50 is too heavy, costing fuel economy and engine thermal transfer capability. The optimal oil is one with very quick startup lubrication and sufficient film strength for normal operation. Amsoil 0W-30 is an IDEAL choice, as is Mobil 0W-30. A close second is 5W-30.