What kind of OCI would you recommend for a 240 (n/a B23F) that is driven about 5-6K miles a year? I have been changing it once a year and not paying much attention to the mileage. We live in Northern California but not far enough north that it snows in the winter. Temperature is usually between 60-70F year round, with a few weeks of 40's in the winter and a few weeks where it climbs into the high 80s/low 90s in the summer.

I usually run Rotella 15w40 and a Mann filter.

I'm asking because I figured this was a "safe" change interval given that the car is not driven much these days. But recently I have noticed that the oil is dark black only 500 or so miles after changing it. I don't recall that being the case in the past. Time for a Seafoam treatment perhaps?

Hi cdcrawford,

Thank you again for the compliment in another thread. Nice and kind of you. Thank you. Specially on the hollow-day sneezin'. (You folks git your quadrivalent flu shot yet if you like them?)

I'd agree with your other respondents. Though I did look inside Art's NMI in hopes for a toy surprise inside. (A miniature Matchbox car as 78 or 79-80 Volvo 242 GT or 164? Ha-ha! With manual transmission!)

Though what Art can write in like three concise and useful sentences I'll have some paragraphs for you.

I'll also be qualitative where Mr. Yount is quantitative in recommending a used oil sump sample for analysis so the lab notes what is making your oil go black so soon after your oil change interval. Oil results analysis will list a host of other items like metal compounds in suspension (piston ring, bearing babbit metal wear), polar compounds like water or engine coolant ...).

A B23F engine? So, how many miles? What year? What type of injection / ignition or a carb (and ignition) if from Canada (with some of their bacon - ha-ha)?

How do you drive your Volvo 240 equipped with B23F? Grocery getter / and / or / with long runs that heats all up including the oil, so moisture gets boiled out of the oil and sucked into the engine for burn through the PCV (positive crankcase ventilation) system.

Not that it matters all too much, yet automatic or manual transmission?

Run a compression test or leak down test at any time?

Good you use the Rotella. Some would say no to synthetics in the RWD Volvo engine, lest after new purchase or after rebuild break-in. My 1991 240 for most of it's life, according to the original owner from whom I made purchase, used Mobil 1 or like synthetic. 10 W 14 or also the 15 W 50 synthetic. He was a USAF officer stationed in Germany when he brought the grey 1991 Volvo 240 new. It has EGR. Now the clear coat fails on it ... anyhoo ..

A cold or warmed engine compression or leak down test? Throttle body wide open. All spark plugs out with a full battery charge.

Pull and gap spark plugs? How do the spark plugs look if in the engine for sometime? Check the gap? 0.28" - 0.32" gap? NGK or Bosch copper plugs? Engine runs and idles smoothly save for the oxygen sensor feedback loop doing it's thing at idle.

Though you use Rotella 15W50, are you sure your positive crankcase ventilation (PCV) is breathing clearly? Synthetic engine oil use would result in a PCV that may not ever clog.

Also, do you have any oil or coolant loss you've measured by mileage interval?

Air filter is clean?

Preheater control flappy valve in the air filter box is working with a new thermostat maybe each year or two? The preheat flappy valve will get stuck to open, and your engine labors to inhale air through the silver accordion style hose between the exhaust manifold heat shield and the preheat air inlet at the bottom, radiator side, of the air filter box. Also effects tune and running in wearmer months or as the engine is up to temp. You have to have the air filter box air flappy valve thermostat operating, or the appearance of connection, for CA-state emissions. No matter the fuel control method integrated to your B23F redblock, that preheater flappy valve stuck "all hot, all the time open" is not good for the engine control; primarily fuel metering and fuel trim as you run around NorCally. (I used to reside in Novato and would set at Dad O'Rouke's Bench at the south end of Bolinas Ridge to contemplate land's end [the freekin'-fog-filled Golden Gate with that giant orange bridge] in various Volvo 240s.)

The PCV, as you know, sucks the cylinder combustion products that pass (blow by) the oil scraping / control and two compression rings at the top of each piston from the engine oil sump. Engine oil sump is the chambers where oil is released and return to the oil pan. Water and combustion by-products boil out, also.

I'll guess your (what year?) Volvo 240 with B23F passes the CA-state emissions test easily or at least well? Have you had to replace items like catalytic converters, exhaust sections, the oxygen sensor? Do you test engine sensors with your trusty and not rusty multimeter? You have the Bentley Volvo 240 service manual bible?)

On the ignition high tension side, the spark is a bright blue using a test spark plug grounded someplace after you have de-powered the fuel injection system (pull the fuel pump relay or fuse panel fuses to depower fuel delivery).

Or rather, specifically, the engine does not run rich; certainly when the coolant is warmed to normal operating temps. Yet to go on further would mean we would test sensor and devices used by engine control to for efficient running, no matter the engine temperature and load.

I'm asking these questions as fresh engine oil that quickly goes black suggests:
- a persistent rich running condition (a concern of engine tuning so you know your engine is burning cleanly).
- and / or / with engine combustion blow by past the piston compression rings.

5k to 6k mile per annum is not really a low amount of miles. I do the same, yet the oil in my B230s remains clear until about 1500-2k miles. By then the oil is sort of brown to brown or so yet you can see the oil dipstick check marks when checking cold engine oil. Well, I guess it goes more quickly in the 1990 240 (li'l red) DL wagon.

Though I'm no expert on the early LH-Jetronic fuel control / Chrysler MPG ignition era 240s and I guess the 700s. You may also be dab-smack in the rotting wire harness era, and so, hopes your engine control wire harness has been replaced. Though by now, it should be replaced, for you to still use it, hopes for.

Some qualitative gnawing for you.

Questions? Comments?

Hope that halps.

Social Sciences Qualitative Boyeeeeeeeeeeeeeeeee
(and his absent Rhetoric PhD. or Dr. of Social Science)
--
Give your brickboard.com a big thumbs up! Way up! - Roger Ebert.

....and just so everyone is clear (even if the oil isn't!) -- color of oil is not a reliable indicator of whether or not the oil is up to doing it's job. MANY race cars out there with very low miles, low time, almost clear oil that has been stripped of its lubricative properties by high shear loads. Conversely, big rig diesels with BLACK oil in the crankcase for 30k miles that analysis indicates is good for another 20k miles. You're kidding yourself if you're using color as a means of determining whether the oil is up to snuff. Don't let your eyes deceive you. Don't guess. MEASURE.

I'd change it based on time rather than mileage. Every 6 months or so regardless of mileage and not worry about it. It isn't a Porsche it's a 240.

If you’re hanging on to the car, I’d invest in a couple of Blackstone oil analyses...let them coach you on effective interval based on science rather than using something like the “color” of the oil.
--
82 242-6.2L; '17 Mazda3; '16 Crosstrek