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Popping from manifold after PCV change

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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jblackburn
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Re: Popping from manifold after PCV change

Post by jblackburn »

Feel free to remove the clip and keep it as a souvenir - it just gets in the way. There are probably torque values somewhere, but "good and tight", will do - don't Hulk Hogan them down.

A 1/4" swivel joint will help you immensely with the left and right lower intake manifold bolts. Should be able to pick one up at Sears or what have you.

Double-check all of your turbo hoses too - hopefully you'll have it back together and working well!

By chance, did you remove the injector/rail when you swung the intake manifold out of the way? It's possible one of the seals there is loose and I imagine that would make some sort of popping noise.
'98 S70 T5
2016 Chevy Cruze Premier


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mercuic: Long live the tractor motor!

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RussB
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Post by RussB »

Here is THE set-up for intake manifold bolts,

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'00 S70, '04 S60 and the never ending quest for Stage Zero

adbalt
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Post by adbalt »

You guys are great. Really appreciate the help. Got everything back together and the popping is gone and the exhaust looks good. Smoke still comes from dipstick and still a small ampount of pressure from oil fill opening (glove test). Is it possible the Mass Airflow Sensor is bad and causing this? When I unclip the the sensor it seems to run a bit better.

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erikv11
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Post by erikv11 »

MAF could be related to it not running so well, but not to positive crankcase pressure (i.e. not to the glove inflating).

What brand is the MAF, is it a Bosch? For a 98, all other brands are very spotty on their reliability. The car shouldn't run better with the MAF unplugged unless the MAF is bad, is the difference really notable? How about when you drive around, is it still better unplugged?
'95 854 T-5R, Motronic 4.4, 185k
'98 V70, T5 tune-injectors-turbo, LPT engine, 304k, daily driver
'06 S60 R, 197k
'07 XC70, black, 205k
'07 XC70, willow green, 212k
'99 Camry V6 :shock: 153k
gone: '96 NA 850 210k, '98 NA V70 182k, '98 S70 NA 225k, '96 855 NA 169k

jblackburn
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Post by jblackburn »

Give it a quick rev by tugging on the throttle cable and see if it still smokes at a higher RPM. If the smoke up the dipstick disappears and glove deflates, your PCV system is good to go.

My car has eaten several MAF sensors. I think it's on #3 now.
'98 S70 T5
2016 Chevy Cruze Premier


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

mercuic: Long live the tractor motor!

adbalt
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Post by adbalt »

It definitely runs better with the MAF disconnected. Hard to tell when driving but it will stall at start up with it connected. I'm going to try to clean it tomorrow. Still not sure where the remaining Crank Case Pressure is coming from. I got this car from a friend and it was severely neglected. After changing the PCV and the oil/filter its running a lot better. Would like to find out where the remaining pressure is coming from though. Is it possible that after completing the PCV and oil/filter the pressure will continue to return to a normal level? Also, a auto store clerk said sea foam in the vacuum lines may help. Have you had any experience or luck using sea foam?

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erikv11
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Post by erikv11 »

Seafoam is debated a lot, do a search there are a lot of posts about it here. I don't use it anymore.

What brand is the MAF? It really matters.

Regardless, sounds like it needs replacing. The parts stores sell a lot of MAF cleaner because the sensors are expensive but it almost never works, for the record. Unless you can see oil or other residue/debris on it, cleaning is unlikely to help.
'95 854 T-5R, Motronic 4.4, 185k
'98 V70, T5 tune-injectors-turbo, LPT engine, 304k, daily driver
'06 S60 R, 197k
'07 XC70, black, 205k
'07 XC70, willow green, 212k
'99 Camry V6 :shock: 153k
gone: '96 NA 850 210k, '98 NA V70 182k, '98 S70 NA 225k, '96 855 NA 169k

jblackburn
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Post by jblackburn »

Vacuum in the PCV system comes from 2 different places in turbocharged engines. At idle, it's coming from that tiny vacuum line on the side of the intake manifold. When revved up, it's coming from the intake side of the turbocharger. That's why I suggested giving it a quick rev to see if the smoke up the dipstick disappears and glove deflates. If that happens at higher than 1000 RPM, you're good - no need to worry about the PCV system anymore, and it is working as intended. A little blow-by at idle means nothing more than the rings are a little bit worn, to be expected at this age.
'98 S70 T5
2016 Chevy Cruze Premier


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

mercuic: Long live the tractor motor!

adbalt
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Post by adbalt »

I tested it at highr rpm's and it seemed ok. Unfortunatley I went out this afternoon and the key will not turn in the ignition now. About at the end of my rope with this thing. Im gonna play aroubnd with it for a bit and if nothing comes around I'm done spend ing money on it already. Thanks for all the help.

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Post by rspi »

When you did the PCV system, did you clean the block holes out real good?

Also, did you do a compression test prior to diving in? A warn motor (rings) will produce head pressure/blowby.
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