1998 S90 with 125000 miles, had regular maintenance under previous owner by Volvo indy shop. I'm running good quality 10w30 dinosaur oil now, changed from syn blend because of leakage.

Sitting at a traffic light today, I looked in the passenger side mirror and noticed some faint blue smoke. Do not panic, I told myself - ask the gurus at brickboard.

Starting with the simple things and common problems, what would YOU look for??

Thanks

Well well .... I did the old "Redneck,/Italian/Polish/Mexican Tune-up" thingy (why offend just one ethnic group when you can offend many) ... we are now a smoke-free zone.

Drove the Interstate 50miles and back, kept the revs around 3500 (I tried 4500 but couldn't bear to hear the car complain). There was a can of Seafoam in the gas tank, just for insurance.

My online Volvo guru said it was most likely a stuck oil ring.

Well well .... I did the old "Redneck,/Italian/Polish/Mexican Tune-up" thingy (why offend just one ethnic group when you can offend many) ... we are now a smoke-free zone.

Drove the Interstate 50miles and back, kept the revs around 3500 (I tried 4500 but couldn't bear to hear the car complain). There is a can of Seafoam in the gas tank, just for insurance.

My online Volvo guru said it was most likely a stuck oil ring.

Oil smoke at idle is typically bad valve guides (and / or seals). Vacuum is the highest and pulls the oil down the intake guide. It burns with a bluish smoke.

Greg

Yup, valve seal. My 250k 95 850 does the same thing. Can happen to the 5 cylinder white block engine as well as the 6 cylinder white block. Your car's engine is essentially the same as the 5 cylinder, since the engine is of a modular design.

How's your oil consumption? If it's not high, I'd leave it alone as you'll need to remove the head to fix it and that gets expensive - $$$.

The best thing you can do for your engine is use full synthetic oil. The leaks should subside with time if you consistently use synthetic. I too made the mistake of using dino oil. Another good thing to do is to use nothing but 91+ octane gas. Volvo recommends using 91 octane in the 5 cylinder so I imagine that is the case in the 6 cylinder. Using low octane can damage the valve seals over time.

crankcase pressure is not the problem - it damn near sucked a rubber glove down into the oil filler hole

thinking it might be worn valve stem seal, based on outside expert opinion

My S90 will show a bit of blue smoke on startup after a hot run sometimes. Not a big cloud, you have to have the tailpipe between you and a setting sun or other bright light...otherwise not really noticeable. If you are not seeing significant oil consumption, then it's not a problem worth spending money on. Mine uses a litre of Mobil-1 5W30 about every 9-10,000km which new car dealers would tell you is well within limits for a brand new car.

There is no connecting fluid path between the transmission and engine, so overfilling the trans isn't the cause. Some early-era automatics had a vacuum modulator on the transmission and there was a (slight) possibility of a ruptured diaphragm in it allowing some ATF to get sucked into the intake manifold. Not on your car...all electronic controls.

Coolant leaking into the combustion chambers results in sweet smelling white - not blue - smoke. And the offending cylinder(s) will show amazingly clean spark plug(s) compared to the others.

If you are seeing the PCV system pulling some negative pressure on the oil filler opening, it is OK. The oil separator box is a bit of a bear to access, and given the rarity of these cars, a non-S90-savvy mechanic would spend some time going to school on yours....with his meter running.

Some early era automatics had a vacuum modulator on the transmission and there was a (slight) possibility of a ruptured diaphragm in it allowing some ATF to get sucked into the intake manifold. Not on your car...all electronic controls.
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Bob: Son's XC70, my 83 244DL, 89 745 (V8), 98 S90, and XC60. Also '77 MGB and some old motorcycles

Blue smoke is because of an overfilled Auto trans.

Check the Positive Crankcase Ventilation (PVC) system for clogs or blockages from the oil separator box through the PCV valve, flame trap or sieve, all teh way into the air intake port. See the FAQ link, below. There is mention of a clogged breather box.

You mention leaks from the Volvo-Porsche white block B6304 engine. Do you encounter an oil consumption problem? How much engine oil do you refill the engine with.

There is also mention between engine compression blow-by, as the oil control ring or the two compression rings are worn in one or more of the six combustion chambers. Verification is best by a leak down test, yet a simple compression test can reveal compression issues.

Lets see the FAQ, from the FAQ link above.

https://www.brickboard.com/FAQ/700-900/EngineSealsBeltsVent.htm

https://www.brickboard.com/FAQ/700-900/EngineSealsBeltsVent.htm#960FlameTrapinB6300Engines

Hope that helps you,

Sundae Morning MacDuffed.

Re: the breather box

I can't seem to find any step-by-step instructions for removing the breather box.

We don't have any Volvo shops around here, but I'm wondering if any competent mechanic would be able to R&R an S90 breather box and hoses ... without spending my time and $$ learning how.

Hi GAcyclops,

Are you in Georgia-state?

Please see the other suggestions in my post.

How many miles? What year S90-V90?

I also utterly forgot to mention, so I under why no one chimed in with ....

"You could have a coolant leak into one or more combustion chamber cylinder."

When you start the engine, and the blue smoke comes out the tail pipe, and you can smell a sickly sweet smell like Volvo coolant or engine coolant mix from the tail pipe, you have a failing cylinder head gasket, warps cylinder head, cranked cylinder head, or worse.

(Mix antifreeze with distilled, demineralized, or deionized water. No tap water!)

If oil leaking into the engine, or passing compression rings, or the PCV is clogged, causing engine oil consumption, you can smell the more acrid then usual exhaust smell.

Is the exterior of your engine basted in oil? After a drive, when you park on a clean surface, do you find engine oil drips?

Welp, no, the 700-900-90 FAQ does provide some more esoteric procedure not well covered by the intersecting host of service manuals for 960/90 series. It's been a awhile I laid my hands on the B6304, but you may have some works to get through to get to the PCV assembly.

I also suggest an engine leak down test, yet after you verify PCV function.

One way to verify PCV function, at least as we do teh engines of Volvo redblocks, is to loosen the oil filler cap, yet let set flat. Start the engine. A clear PCV and an engine with a well sealed air intake-vacccum systems means the set, yet loose oil filler cap does not rattle. It sets still if the engine idle does not knock it off.

Another way is to pull the PCV hose where it terminates at the air intake (manifold) port. Remove the oil filler cap. Wipe the hose end, or wrap so you do not get much oil taste, and blow. You should be able to hear the air you displace through the engine oil sump space as you exhale. Should be easy to exhale into the engine oil sump.

I'm not sure the PCV flame trap, sieve, or valve design B6304. I think it is open, or has a sieve. You should use only synthetic oil, like Mobile 1 or better, in the Porsche-Volvo B6304 white block engine.

So, as for manuals, you can search the i-net, eBay, and elsewhere for the Volvo factory green manuals. The Volvo factory green manuals are written for the well-trained mechanic, yet are truly usable and approachable. I think you have Hayne's, yet with Hayne's manuals, watch it with specifications for fluid type or torque value.

So, using Google searching for: Volvo 960 S90 V90 repair manual

We find:

- www.volvotips.com - hosts portions fo the Volvo OEM factory service green manuals. Hosted in Flash or Shockwave or Mirosoft Silverlight.

- Volvo 960 / V90 Service Manual - Google Docs

FCP Groton.com has the manual on CD
- https://www.fcpeuro.com/products/volvo-repair-manual-cd-rom-940-960-s90-v90-tp-51957

( I believe iPd USA also sells Volvo repair manuals on optical disc or for download. Yet you seem to have freem repair manual options in abundance.

- If you buy a produced Volvo VADIS or Volvo service manuals that are used, set your antivirus to scan on insert. Then again, in all operating systems, certainly Windows, fully disable autorun and autoplay.

And check the results that seem to indicate PDF files that contain Volvo manuals you can use. Just be sure your anti-virus is current and running to scan on download or file open.

As for mechanics, you have resources. I dunno your state, so here goes:
- https://www.brickboard.com/SHOPS/
- http://www.volvomechanics.com/
- http://www.mechanicsfiles.com (also Click and Clack?)
- http://www.cartalk.com/mechanics-files (of Click and Clack Car Talk Fame)

I miss Click and Clack. Love hearing their show each week. Lovely. Funny, and useful, and honest.

Research listed repair facilities. Check the BBB. Check the websites with opinions, yet take a grain of salt on those.

You should be able to find an illustrated service manual. The PCV system is about the same across the 960/90 model range offering, yet am not sure.

When you do start tugging on stuff, please keep in mind, the PCV oil separator breather box is made of ABS plastic, and can become brittle. So, research what options you have should you need to replace the breather box and seal under neath it. Verify connected vacuum line condition.

If it is really bad in there, you may want to consider performing a full review of the air intake system, including the throttle body.

With the B6304, how are set on other maintenance matters? The timing belts and tensioner pulley get replaced like 70k to 100k miles. Use ContiTech if so as they should have a kit, from iPd or FCP and elsewhere, I believe, that comes with replacement tensioners. Unless these are hydraulic t-belt tensioner on B6304. Oh, I forget, again.

I feel you may have other service issues pending.

Have you checked the OBD-II? With your new downloaded, and free Volvo 960-90 service guide, and the owner manual that came with your 960-90, check the OBD-II. With the instructions, you can go to an auto parts store like Kragen, Schucks's, Autozone, and what have you. (Call ahead). Check all OBD codes. Find out what they mean. Can be a guide to prevent other issues before they cost much more to repair.

Does that help you? I may have forgotten some details.

The B6304 is an awesome engine, but care for the engine and entire car requires a much high level of service and care vigilance.

I only wish they came with the M56 or M90 manual transmission in the states. Up tune these to Euro-spec tune, and you have quite a performer on par with perhaps a BMW 5 or 7 series with their lovely BMW I-6 engine. (I forget the BMW engine model numbers.)

I do like the 90. Just can't care for it. Barely can care for my three 240s.

Sorry to go on so long. Sorry about that.

Questions?

Hope that helps.

Thank you.

Buttermilk MacDuffy's Tavern: Lunchtime Special - A BLT on Rye a glass of buttermilk!
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The Volvo 164: The Mightiest of All Volvo Automobiles in Perpetuity