We have a friend who is a certified Volvo mechanic recommend we use Rotella 15w-40 oil in our Volvo. We have been doing so for several years now. All seems well, but I thought I would see here what you guys use and if you have other advice.

We are in a 93 240. Gas engine.

 

10-30, like Volvo recommends. 15-40 probably fine too. The engine is the last thing that will go in RWD Volvo with B230F/T, just change the oil now and then. Many more ignore the other fluids like ATF, coolant, P/S, brake, etc. More important not to overheat it, ever!

 

I run 10w40 straight sometimes a mix with 10w 30
no problems and I am now well over 2 million miles on my 740
Goldenblock

 

Where do you live? SAE winter viscosity grade 15W isn't a good selection for wintertime.
Likewise, SAE viscosity grade 40 isn't what Volvo recommends.
Which flavor of ROTELLA® are you using? Most of them are designed for Diesel engines and include additives that protect against conditions that your spark-ignited engine doesn't encounter. It won't cause any harm, (probably) but you'll be paying for stuff you don't need or want.

I live up north, use Mobil-1 0W-30 and a premium filter, and change them every spring. (1993 940 naturally-aspirated redblock)
I haven't done an engine teardown or oil analysis to know how effective they are. It runs well and has good, uniform compression after a quarter million miles.
Realistically, I probably don't live far enough north to actually need 0W, but it's the same price as every other viscosity grade.

Before anybody gripes about "too thin", review the difference between "viscosity" and "viscosity grade", 0W-30 oil exhibits the very same viscosity as 10W-30 or 5W-30 at 100°C. (9.3-12.5 mm²/s) It's only less viscous in the cold, where every oil has more than enough viscosity.

Back in the day, Mobil-1 was dreadfully incompatible with leaded gasoline.
I don't know whether that's still true, if it's true for all the different flavors of Mobil-1, or if it's relevant.

 

when we bought our 87 240 new, after the first few dealer oil changes, I was doing my own changes using the same oil I'd been using on my VW Rabbit and Jetta, Castrol GTX 20W50. A indie volvo specialist told me, TOO THICK! and that I should use 10W30, so I switched, and indeed, it ran much better with 10W30, lower oil temps, smoother idle, better power and fuel efficiency. now, I live where its very temperate, rarely over 90F, and almost never freezing or below. if I lived where we had real winter, I'd consider using a 5W30 synth in the midst of winter.

 

I don't know the mechanic's reasoning behind the oil choice. She was doing some other work for us and this came up as a recommendation. She was driving an older 240 herself and had been working on them professionally for 20+ years (Volvos anyway, not necessarily 240s, I suppose).
We live in central NC with moderately cold winters. Summers are a little hotter than Pierce's, if indeed he lives in my old stomping grounds of California's 37th parallel. (I grew up in Half Moon Bay. Are you near there?)
I will have an oil change coming up. I may think about a change to see what happens.
Thanks for all the advice here.

 

indeed, I'm in Santa Cruz, maybe 50 miles south of HMB... we get a little more sun due to the way the mountains wrap around us and that we're south facing, but pretty much same otherwise. I'm about 3 miles inland and up 300 feet, which also adds about 10F in the summer vs. being on the flats right near the coast.

 

i run 5w-30 in the winter, and 10w-40 in the summer in both of my 240s.

 

Why??? Engines run at the same temperature all year 'round. That's a thermostat's entire reason for existence.

 

because we regularly see winter temperatures of -15 to -20*F, and summer temperatures of 95*F.

 

10W30 handles those extremes just fine, when its really really cold, just let the engine warm up a bit more before leaning too hard on the gofaster pedal.

I've driven a Volvo redblock through death valley in the summer with 116F in the shade with 10W30, and I've been up at lake tahoe in deep sub-zero F conditions with the same oil. a bigger problem is your battery.

 

5w-30 works just fine for me in the winter. you are welcome to put 10w-30 in yours. i never let my car warm up; start it, put it in gear, and go.

i’ve been to DV, too, with my ‘87 4runner. 126*F the day we arrived in late july. ran 10w-40 for it, as well. never had an issue on our 8700 mile, 32-day trip.

 

I was reading some of your responses to my wife. At first, we could not remember the reason for the Rotella recommendation years ago. Then she recalled that we were dealing with a number of chronic oil leaks. I think the thicker oil was one way to slow the leaking. We think that was what was behind the recommendation.
We are not dealing with leaks now, so I think I will switch to the thinner oil at my next change. Maybe then I'll find out that the thick oil was working, and to leave it alone!

 

the diesel oils *used* to have more zinc (ZDDP) in them, similar to the standard oils of the 1980/90s. A few years ago they reformulated the common diesel oils to better suit the new generation of DEF (Urea) injection diesels (Mercedes calls these Blutech), and they dropped the high zinc as it interferes with the DEF, so now those oils aren't as 'special' as they were before. they are still very heavy duty oils, designed to take the extra heavy beating that high compression diesel motors give them.... I've been using Chevron Delo 400 15W40 in my Mercedes 300/320 engines for some years now, originally due to the high zinc, and right now because I also use it in my Ford 7.3 Powerstroke, and it comes in gallon jugs, which is more convenient than quarts when you have an engine that takes 8 quarts (the mercedes) or 14 quarts (the Ford). Costco sells 3 gallons of Delo400 for like $40, so at $3.33/quart, its still a pretty good deal for a semi-synthetic oil, but IMHO 15W40 is too thick for a 'red block'.

[15W40 is the optimal weight for a Mercedes M103/M104 straight 6 engine in a temperate to hot climate, and usable down to 0F]

 

From the Owner's Manual: https://volvo.custhelp.com/app/manua...1993/model/240
Page 74: https://volvo.custhelp.com/app/manua...ual/om_id/1146

 

I use whatever is on sale at my LAPS. 15W-40; sometimes 10W-40. I never use synthetic in this car; but I do in all my others. I do use a good filter; Mann, usually. 5000 mile OCI are my usual on the dino oil, though

Glossary
LAPS-Local Auto Parts Store
OCI-Oil Change Intervals