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Crankcase pressure from boost

Help, Advice, Owners' Discussion and DIY Tutorials devoted to the second generation C70, S40 and V50 Volvos -- awkwardly model year 2004 ½ onwards -- plus where to go for advice and discussion on Volvo's sporty C30 Coupe powered by Volvo's ubiquitous inline 5-cylinder power plant.
mikesavara
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Crankcase pressure from boost

Post by mikesavara » Fri Jan 31, 2020 12:07 pm

Hi there,

I have a 2008 S40 T5 that has some crankcase pressure issues. I replaced the PCV system 2 years ago when the diaphragm tore. I have some oil leakage around the TCV valve area on the Turbo and a few days ago my rear cam cover on the intake side fell out (assuming it was from pressure). I am currently driving with the oil dip stick out to avoid seals getting pushed out, but oil is shooting everywhere due to that.

I am getting good vacuum at idle using the glove test, but I believe my car is increasing crankcase pressure when it is driving at boost - how do I test this theory, since I can't get it to boost in park?

If it is having excess crankcase pressure at boost, what are my remedies? I've been reading about something called a "PTC" nipple but I'm not sure where that lives on the s40 - somewhere on the intake?

I also have read about a Hollow Screw or Banjo Bolt and bought one from FCP but again, not 100% where that lives in order to replace it. I heard they get clogged with carbon and can cause these symptoms. Is that in the IM?

I also think it's possible that my TCV valve is broken and needs replacing, but I'm not getting any CEL or limited boost feeling. The TCV valve area may be leaking just due to the pressure issues.

Any help is appreciated! I can replace the PCV system again but don't want to do that if it's not useful.

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Re: Crankcase pressure from boost

Post by RickHaleParker » Sun Feb 02, 2020 3:37 am

It sounds like you are getting Blowby, to much for the PCV system to process. Is there a raw gas smell coming from the dipstick tube? You can use a plastic hose over the dipstick tube to find out.
--------
Platform: P80 1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.
Platform: X40 (Nedcar) 2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.
Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
Platform P2 2004 S60R, B2524T4, AW50/51 AWD, Bosch Motronic 7.0, BorgWarner K24 turbocharger, Plant Ghent Belgium.

mikesavara
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Re: Crankcase pressure from boost

Post by mikesavara » Tue Feb 04, 2020 9:45 pm

Hey! I'll take a sniff soon - lots of oil is coming out of the dipstick tube since i've run it without the dipstick fully in to prevent seals being pushed out.

I also tested using a manometer - I got -.41 PSI at Idle and upwards of 2.0 PSI (positive) when boosting. This makes me think that this is when the blowby/positive crankcase pressure is happening.

I am going to replace the PCV system and check the lines going into the sump, as well as the PCV Banjo Bolt going into the IM to see if that changes anything with the pressure in the system.

One other thing: I may have screwed up and put in slightly too much oil, like maybe .5-1 extra quart. Stupid move. Could this cause my woes?

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Re: Crankcase pressure from boost

Post by RickHaleParker » Tue Feb 04, 2020 11:01 pm

mikesavara wrote:
Tue Feb 04, 2020 9:45 pm
One other thing: I may have screwed up and put in slightly too much oil, like maybe .5-1 extra quart. Stupid move. Could this cause my woes?
If you see any oil foaming or low oil pressure correct that immediately! By doing a oil and filter change.

A little over would be much of a problem but if it is too much over, Air and Oil aerates ( Crankshaft dipping into the Oil reserve) . Which can lead to Catastrophic engine failure. Oil pumps are designed to pump liquid not foam.


If it is blowby. It might be a stuck ring. It is possible to unstuck rings with Seafoam.

The data from a compression test would be real helpful.
--------
Platform: P80 1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.
Platform: X40 (Nedcar) 2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.
Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
Platform P2 2004 S60R, B2524T4, AW50/51 AWD, Bosch Motronic 7.0, BorgWarner K24 turbocharger, Plant Ghent Belgium.

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Re: Crankcase pressure from boost

Post by Mikesavara1 » Tue Feb 11, 2020 7:50 pm

Hey all, so I'm scheduling an inspection later but I replaced the PCV system including the two hoses and today I had a rear cam seal pop out due to pressure. The car has vacuum at idle but generates crankcase pressure In excess of 2 psi when boosting still. Can a faulty turbo cause this? Like if it's leaking or the TCV is slowed (it's currently covered in oil) could this cause pressure to go to the crankcase at boost?

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Re: Crankcase pressure from boost

Post by Mikesavara1 » Tue Feb 11, 2020 7:52 pm

Also, the oil level is back to a normal amount now. I don't think it's the rings causing this cause if I'm at idle, and the car is parked the vacuum remains in crankcase pressure when revving, it's only when boost is active that positive pressure happens.

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Re: Crankcase pressure from boost

Post by jimmy57 » Wed Feb 12, 2020 10:05 am

InkedP1 turbo_LI.jpg
InkedP1 turbo_LI.jpg (596.92 KiB) Viewed 75 times
On the turbo on P1 models is a check valve fitting that is supposed to let crankcase pressure in but vacuum lifts the ball and seals it. The check valve goes in the location circled on the turbo pic. The ball may be gummed up, lifted and stuck. Or the hose to it is crimped or obstructed.
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mikesavara
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Re: Crankcase pressure from boost

Post by mikesavara » Wed Feb 12, 2020 12:22 pm

Thank you so much Jimmy57! I think that is a really good lead. I have oil on the turbo, so it makes me think that there is an issue with this breather hose assembly. I believe this is the part https://www.fcpeuro.com/products/volvo- ... 24#fitment

I have ordered this from Volvo dealership to be delivered tomorrow and I'll try to take it apart shortly. I think it should be fairly easy to get to from the top of the engine with a crowfoot wrench and some persistence. Thank you all so much for all the support! Volvo wanted to spend "2-3 hours" of diagnostic time working on this because I've been working on it on my own. This system isn't that complicated, just takes a lot of trial and error sometimes...

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Re: Crankcase pressure from boost

Post by Mikesavara1 » Sat Feb 22, 2020 8:36 am

Wanted to loop back with this thread and let folks know that I believe this issue is fixed! I replaced the check valve (it's harder than I thought, important to get a internal snap ring pliers) and took it for a test drive with my manometer set up. It still goes above and generates positive crankcase pressure, but to a lesser degree and only at full boost. I believe this is likely normal, atleast for a car with 172k on the engine. The good news is that no seals have popped out all week and the engine is dry. Now to do a deep clean of the engine bay after all that oil getting thrown around before! Thank you all!

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