S70: Pcv

[.JCJ.]

Hi Gents.

My 1998 R REG VOLVO S70 2.5 10 VALVE PETROL AUTO CD. I asked a Volvo specialist garage when in for service to check the PCV system on this non turbo, was told this had been done and blown through, When at home after 50 miles, I lifted the oil stick out with engine running and found a small amount of smoke came out, Phoned the garage and was told a small amount is ok. Only done 145000 miles with full service some times tow a caravan with oil and fillter changed 4k and serviced yearly in garage.I was under the impression that no smoke should come out.What is the verdict from you wise members.Do I need to purchase a VOLVO PCV breather system kit non turbo, Price wise I hope not.

[Paffel]

Can you confirm, what work did the garage actually do around the PCV? Look at it from the top, take off pipes, etc...

[RollingThunder]

I suspect it hasn't been a proper job too - the PCV components need to be replaced at 100-125k IMHO. Blowing them out with compressed air isn't maintenance

Its a pig of a job which is why they possibly didn't go down the replacement route - the intake manifold has to be removed for example.

Its possible that blowing it through has loosened some carbon/oily gunge and compacted it in the oiltrap.

I'd ask the garage what exactly they've done...

[.JCJ.]

Hi Gents

Thanks for your repliers, I phoned the garage and was told they removed the oil filler cap and oil stick and two pipes then blocked one end and air pressured and was clear. He said it was possible that a restriction is further down. He said on car that are nearly new you can still get a small amount of smoke, I then told him I had removed the oil filler cap and sealed over the top with a thin rubber glove pressure was coming out of the engine.Was told he had been on volvo for 35 years and it should blow out. I think Its a sealed system so it should suck in. So should it suck or blow pressure. asked him to phone back full with full cost of replacement. Many thanks .JCJ.

[Paffel]

I've always known a blocked PCV to blow out (look up the jiggle test - loosen the oil cap and see if it jiggles about), and a clear PCV system will suck the cap in.

There are some very experiences members on here who will give you a confirmation of this. Blasting the tubes free will help interim but where will the crud end up... I'd take it off and inspect the components properly, replace if necessary.

Not a difficult job, just removing the inlet manifold has a few tricky bolts where it attaches to the cylinder head, so an assortment of 10mm spanners, sockets and universal joints will help.

[RollingThunder]

I'd be embarrassed to even admit to doing that and calling it a PCV service lol.

You need to replace the oiltrap as a minimum as its in there that the more solid blockages usually occur. I guess you could get away without changing the other PCV hoses but I usually renew the lot. Yes it costs a bit more, but it'll protect against a blown rear oil seal which is a major job to renew..

Good thing you were suspicious about it!

[mikealder]

You need to find another mechanic as the one you took it to is a pillock, there should be a slight negative pressure in the crankcase at idle if the PCV is working correctly, if it inflates the glove then the PCV needs work.

By blowing compressed air down the two pipes that are accessible without major work the air will simply go through the PCV tank and straight in to the sump via the crankcase blow-by port in the PCV tank.

The port that usually sludge's up (and often blocks) is the oil drain port from the PCV back to the sump, the only way to clean this out is to remove the inlet manifold and PCV tank, after cleaning it out attach a 5/8" rubber hose to the port and try to blow through it, if you hear bubbling from the sump you know the port is clear, if you can't blow through it you need to further address why it is blocked which could even lead to removal of the sump to clean out the PCV oil drain channel - Mike

[.JCJ.]

Hi Gents.

Due to ill health I am now unable to do the work myself, (Thats old age ) I have bit the bullet and booked into the Volvo main garage nearer to my home for a full replacement. The volvo specialist who said it should blow and not suck, has put me of letting him do the work, On checking I found he had put the wrong tyre pressure in the front. I would like to thank you for all your repliers .JCJ.

[Paffel]

Glad you've taken some good advice on board.
If you were closer to me (Leicestershire), I'd offer to do the job for you, save you a few pounds!