Does anyone have an opinion about mixing Synthetic and Regular oil...say about 50/50. Will this defeat the purpose or as I'm hoping will reap the benefits of the Synthetic as well as lowering the overall cost.
--
-Cool Volvo- 1982 240 4 Spd OD w/ 238K, 1989 240 5 Spd w/ 227K. Past proud owner of 1966 122, 1968 144, 1970 145, 1972 144, 1980 245

Amsoil offers a blend, but it does allow the extended drain interval of their pure syn. they recommend 7500 with the blend.

Here is my mix:

3L XD-3 full synthetic 0w30
1L XD-3 regular oil 15w40

I had 6L of the 0w30 so I wanted it to last 2 oil changes. I also called Imperial oil canada and 2 different techs said the blend was acceptable.

I'd be inclined to mix identical brands to maintain some type of similar chemistry. But that is an opinion only.

I'm sure the oil mfg must realize folks will stop at a gas station and put any oil in they can find so it can't be bad.
--
Norm Cook; Vancouver BC; 1989 745T 212,000KM

red block volvo engines are not sensitive to this.

Volvo only specifies weight and API service quality. Change frequency is the best way to "be nice" to your engine.

--
Stef (81 245 B21A SU M46 3.91 330000km, 81 244 BW55 3.31 220000km)

NO, your not defeating th epurpose of running the syn in there at all!! actually, your gettign a much better "blend" of oil than what's commonly sold in stores as "syn blends"-as those contain, at best 20% syn...the rest is alll conventional oil. I've done this in the past on cars with great success. The key is, is to stick wiht the same viscosity for all the oils, as well as the same name brand of oil, to prevent any clashing of additive packages.

A good blend would probably be Castrol GTX-2 liters and 2 liters of Castrol full syn, all of the same viscosity i.e. 10w30.

I really great oil lately on BITOG has been the Rotella T, as well as the Esso XD3...both offer excellent additive packages, and can easily go well over the 5000kms that's the usual limit on most oils/

Good luck!

- A good blend would probably be Castrol GTX-2 liters and 2 liters of Castrol full syn, all of the same viscosity i.e. 10w30.

... except here in the US, where most of the Castrol Syntec isn't a true synthetic, but just regular oil refined to synthetic oil characteristics.

-- Kane ... who uses Mobil 1 in the turbo.
--

While I would never deliberately mislead anyone, take into consideration that any info and advice was provided at no cost to you.

That's good information. I didn't realize that the Syn blends were only
20% Synthetic. I wasn't planning to use the same brand, but I will stick
with the same weight. I'm hoping to keep the plumbing much cleaner.
--
-Cool Volvo- 1982 240 4 Spd OD w/ 238K, 1989 240 5 Spd w/ 227K. Past proud owner of 1966 122, 1968 144, 1970 145, 1972 144, 1980 245

most are only about 11-14% syn

And yes, this will really help clean things up nicely.

A theory of mine is that on a car that's usually run on dino it's life, when you switch it up to a full syn, it'll blast off all the sludge so fast, that you'll end up with leaks and burning. To prevent this, I have started doing a slow transition from dino, to full syn. You can start out doing the 50/50 mix, then if there's no leaks or burning, at the next OCI, (if you ultimately wanna go full syn) try 75/25, then finally the full syn on the last change.

I tried this on my GF's 97 Escort that was run totally on dino it's whole life. Now I'm running M1 5w30 at 20,000km change intervals (this oil can easily handle those intervals, esp. with the filter chage and top-ups every 10kms in-between.

glad to be of service :)

I've switched four cars over to synthetics. All had over 100,000 mi and two had over 200,000 miles. None of them had any problem with seal leaks or sudden 'floods' of loose sludge. I'd have to say the engines had had regular dino oil changes so there probably wasn't heavy sludge in the engines.

What I have noticed in every case was a dramatic reduction in oil usage. On most of these cars I found I would need from 1/2 to 1 quart of Dino oil about 2000 miles after an oil change. I'd add this and then change oil and filter at 3000 miles. When I switched to synthetic, I found that no oil would be needed until about 4000 miles. I change the synthetic oil at 5000 miles which is probably much sooner than necessary.

I figure that the oil usage in dino oil is due to smaller molecules working their way past rings and seals and also a breakdown of the oil molecules into smaller parts which are then lost. The oil usage in dino oil seems to accelerate as the oil approaches 3000 miles but this does not happen with synthetic oil. I've used both Mobil-1 and Amsoil.

I've also noticed that the oil usage varys quite a bit with the engine. For example, my late, unlamented, Taurus 3.8L V-6 never used a drop of dino oil between 3000 mi change intervals. My old Mercedes 300E uses less oil than any of my Volvos. The Volvo 4-cyl red block engines have all used about the same amount of oil regardless of their mileage.

Just my experience, your's may vary. I hope this doesn't start another oil war!

My experience pretty closely duplicates Jim's. Many high-mileage changeovers to synthetic, no leaks, no problems of any kind, some reduction in oil consumption.
--
Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD; hobbycar 77 MGB, and a few old motorcycles)

"What I have noticed in every case was a dramatic reduction in oil usage."

Jim, this is interesting ... I've recently switched over to synthetic in the my '89 745t so we'll see how the consumption is.
--
Norm Cook; Vancouver BC; 1989 745T 212,000KM

I'm a believer in synthetic formulas in all lubrication and hydrostatic system applications. I have had to replace more than the odd seal or gasket when switching vehicles from dino to synthetic, but I have never regretted going to the extended service intervals, improved performance, and component longevity that is offered by engineered fluids from the crankcase to the calipers. IMHO, Volvos are worth the extra investment. Regards,
--
1990 244DL@168k aka 'Vicki', daily driver; 1994 854 ti+ @126k, being reconstructed as rally car; 1997 Chevy Tahoe LT @160k, boat hauler/family wagon; wifemobile 1995 FROD Exploder Edgy Bowel Edition @137k; small fleet of 98-01 Crown Vics (taxis); etc...