I'm trying to decide on a synthetic oil for my 15year old 740gl and it occured to me that my volvo forum friends might have some insight to the inquiry. So which is it and what type should I use for my b230f engine? How long of interval with synthetic is reasonable?

 

I use Castrol synthetic in ALL of my autos and have done so since 20 years or so ago...............one of my autos is a 1965 Austin Healy. So do not let the fact that your auto is "old" colour your decision! Incidently, BMW uses Castrol in all of their autos for years. It is packaged under a BMW label.......................but it is the ordinary Castrol synthetic...............until you get to the E-46 M-3 which uses a 0w-60 that is only obtainable from the dealer.

 

I agree with the castrol.Volvo even reccomends using it.The new cars have it stamped on the oil filler cap.

 

I won't try to point you towards one brand or another...though I use a full synthetic. (Look at the label before you buy...some "synthetics" are made from...regular "dino" oil!)

Just remember this, while synthetic oils have the potential of lasting a good long time in continuous use without breaking down, they can still become contaminated with corrosives from cold starts, blow-by, etc. So I don't leave them in for more than 6 to 9 months.

 

I would highly recomend you not to use synthetic if your engine has had regular oil for over 2,000 miles sine break in period. But if its a rebuilt/new engine, standard oil for 1st 1,000 miles then synthetic for the rest of the way.

 

Why would it be bad to change over a high mileage engine to synthetic? I'm considering the change for that reason specifically.

 

There is alot of different opinions about switching over with high milage.
Some say it does more harm than good.
Some say synthetic is better no matter what.

I myself have never seen problem switching from regular to synthetic in high milage engines.

 

I recently switched to mobil 1 and didnt notice any decrease in performance, very little increase either but i guess it takes a while. A friend of mine said you might notice some more seeping because synthetic oil breaks down the mineral deposits which are helping seal the engine, I didnt notice any seeping though.

 

Having more than 20 years experience with synthetic................Mobil 1 was the first, I have NEVER had an issue with changing from "regular" oil to synthetic. Please recall that it was Mobil who first sold synthetic oil................ALL the other oil companies started the stories that converting to Mobil's synthetic would cause seals to leak. That just was not true and when Penzoil and the others began selling synthetic oil, you never heard another word of leaking seals. Lastly, I have an Austin Healey...................they are notorious for oil leaks. My Healey I purchased new in London in 1965 and of course used "regular" oil. In the 80's I changed over to Mobil 1 and...................still no leaks to this day. When Castrol began selling synthetic I changed over and use it exclusively.

 

I just joined this forum and it looks great. I normally do most of my own mantenance but have an '04 S60 that I just purchased at the end of lease. The dealer did all of the oil changes as part of the lease and I just went with the Castrol regular oil. I am probably going to change to Synthetic at the next change and have a couple of questions. Amsoil says you can go 15K miles or yearly on an oil change. Anybody doing that??
If I am going to change every 5K as someone else said in this post, I see no sense in paying more for Amsoil than the other synthetics.

 

[sm=bangbang.gif]

It's your choice, in the end.

 

Link for this laboratory study is dead, but it was well done and independent of oil company interference.
Top-rated oils and filters (Mann not included). Myself, I have found best results with the Pennzoil High Mileage (295k) -
seems to greatly minimize leakage and oil burn off is measurably reduced. I must say that full syn made my 745 drip all over.

Maximum lubricating properties for oils and filtration construction quality and performance. Filters were bandsawed open, deconstructed and internals compared.


Oil/Synthetic
-----------------------
1. Mobil One Tri-Syn 0/30
2. Chevron Super-Syn 5/30
3. Mobil One Tri-Syn 5/30


Oil/Mineral
-----------------------
1. Quaker State 5/30
2. Shell Fire/Ice 5/30
3. Quaker State 10/30
4. Shell Fire/Ice 10/30

Oil/Blend
-----------------------
1. Castrol Syntec 10/30


Filters
------------------------
1. Mobil 1 (expensive)
2. Purolator Premium Plus
3. Pepboy Proline (same as PPP)
4. Napa Silver or Gold
5. Motorcraft (PPP based)
6. AC Delco Duraguard
7. Fram (don't believe the hype)

 

I vote for Amsoil,it the long run its better for your engine,Amsoil is an true synthetic,not an over blended dino oil.Mobil 1 is allso a very good oil-The best Amsoil hands down.

 

I switched from dino oil to Mobil 1 on a high-mileage Toyota. Within 1,000 miles the engine started burning oil and the seals started leaking. I had to junk it shortly thereafterbecause of lack of compression and oil leaks.

I'm not saying it was caused by Mobil 1. Maybe it was just a coincidence. Let's just say I would never again switch from dino to synthetic on a high-mileage vehicle.