Blue smoke upon acceleration, after decelerating in gear, M66

imaV70Rdriver · Post by **imaV70Rdriver** » 04 Apr 2019, 13:22

Hi, I have a 2004 V70R with the M66 transmission. If I coast or decelerate in gear, either along the highway, or to a stop sign or traffic light, I get a huge puff of blue smoke when I get back on the gas.
Seems to be pulling oil from one place to another when "engine braking", and then it clears upon acceleration.
Any ideas regarding where to start? PCV system? Turbo? Runs great otherwise.
Thanks
PS This smoke condition does not occur if I throw it into neutral and coast (to a stop or not) and then get back on the gas.

Post by **RickHaleParker** » 04 Apr 2019, 23:20

Blue smoke on acceleration tends to be the PCV system. Do the PCV glove test.

Post by **abscate** » 05 Apr 2019, 04:21

Oil After a hill descent is classic piston oil ring failure but the rings on these cars are very robust., so I would concur with a PCV and/or valve stem seal job.

PCV evaluation for pressure first

Compression test
Cylinder head valve seals..not too bad a job

If that doesn’t fix it,

Post by **erikv11** » 05 Apr 2019, 09:52

Check PCV because it is low hanging fruit but cylinder head valve stem seals is also likely. Differential diagnosis: it would smoke at startup in the morning, does it?

The valve stem seals is a nasty job by my reckoning, but I still haven't actually done it.

imaV70Rdriver · Post by **imaV70Rdriver** » 05 Apr 2019, 17:35

Thanks for the thoughts and suggestions, I just did the glove test, and if I comprehend, the PCV system is functioning properly. Please correct me if I'm wrong.

When I started the car from cold, with the glove sealed over the oil filler hole, the glove inflated "instantly" and then deflated just as quickly (one or two seconds). Then the glove was slowly sucked into the valve cover as vacuum built. After the idle settled down, it sucked in even further. I removed the glove, then put it back on as before. This time the glove sucked in very quickly, much faster than it did upon cold startup. When I blip the throttle, the glove looses some vacuum but doesn't inflate. When I rev it, the glove again looses some vacuum but does not inflate.

About three months after buying the car, it started running poorly. When I checked the plugs, all five sparkplugs were loose, and three of the electrodes had broken off into the engine. The dealer who failed to tighten the plugs properly would only replace the plugs, and sent me on my way. I was very concerned that the broken off electrodes might have caused internal damage to the cylinder walls, but that was five years ago. I'll do a leakdown test, and if there's anything odd, I'll do a boroscope.

I also want to know if it could be the turbo? No point digging into the engine to do stem seals or rings if it isn't necessary. Any ideas on turbo tests or links to such?

Post by **erikv11** » 05 Apr 2019, 17:49

Yes, it passes the glove test with flying colors, this isn't a PCV issue.

Does it throw smoke on startup after it has been sitting for some time, like overnight?

Post by **RickHaleParker** » 05 Apr 2019, 18:37

imaV70Rdriver wrote: ↑05 Apr 2019, 17:35 Any ideas on turbo tests or links to such?

Remove the Air Pipe between the Turbo to Intercooler and the air pipe between the Air filter to Turbo.

With two White Rags wipe down the inside of the Air Pipes.

If a White Rag picks up a lot of oil in the pipe between the Air filter and the Turbo , the oil is being sucked up by the PCV system.

If the Filter to Turbo is clean and there is oil in the Turbo to Intercooler, the Turbo is the source of the oil.

tardcart · Post by **tardcart** » 05 Apr 2019, 19:37

It wouldn't be the turbo, that would smoke on hard acceleration. If you visualize engine breaking the throttle body is closed and there is high vacuum in the intake and piston chamber. therefore only valve seals, intake vac line to PVC, rings, head gasket. can supply oil. I would doubt head gasket and PVC (tiny 5mm line) so that leaves valve seals. I wouldn't consider rings except you could have scoring of the cylinder if the electrodes really broke off but Im skeptical of that. just because the plug is loose the electrodes can't fall off as far as I know. why do you say the spark plugs were loose and how did you find out?, the dealer wouldn't have fessed up. The normal result of a loose spark plug is seeing it shoot through the hood.

ignatz · Post by **ignatz** » 06 Apr 2019, 04:22

Just curious, what's your oil consumption?

imaV70Rdriver · Post by **imaV70Rdriver** » 06 Apr 2019, 17:02

erikv11; No smoke at all, on cold startup after sitting overnight.

RHP; I'll take those pipes off and check for oil in either pipe.

tardcart; I removed the plugs myself. I know!
From front of car,
Sparkplug one, 1/2 turn loose, no ground electrode
two, 1/2 turn loose, no ground electrode, and broken insulator
three, 1/4 turn loose, virtually no gap, the ground electrode was almost contacting the spark tip (or whatever it's called)
four, 1/2 turn loose, no ground electrode
five, 1/8 turn loose, ground electrode intact, ok gap, fairly normal looking

: Courtesy the former McKevitt Volvo, Berkeley

Sorry ignatz, oil consumption is very high, I just feed it on demand. Probably one quart every 500 miles or so. But that was when I was still downshifting and engine braking, now I coast in neutral and use the brakes a lot more! No huge smoke puffs, therefore I assume I'm burning (using) less oil now.