crankcase ventilation
 

In all my 220K+ miles I have never looked at the crankcase ventilation system on my car. But for the fact a member is selling a oil catch can here I would never known I had such a system.

As a firm believer in the addage ..if its not broke don't fix it

Is there a simple way of checking this system, as it appears you have to dismantle half the engine to get at the components - altenator, power steering, inlet manifold.

I have read else where about checking to see if theres a vacuum at the dip stick and oil filler cap, and when there is a problem oil appears to be sprayed all over the engine bay, which I don't have, nor do I have any crud in the filler cap. Engine has been feed fully synth since birth @ 10K intervals.



Cheers

Bob

If you loosen your oil filler cap...it should pull back against the engine....if it pushes against your hand you may need to sort the PCV. ( breathers ) It only requires the inlet manifold removed and isn't a bad job. Just a bit fiddly.

It's an easy job but will take a few hours, the N/A engines can be completed in around three hours but the Turbo models take a couple of hours longer due to you having to take more pipes off and some difficult to access bolts.

The last one I did was a 54 plate S60 Turbo and to change the inlet manifold gasket the thermostat housing had to be unbolted from the engine block which means draining the coolant system - Really depends upon the year and type of engine fitted but it is something you can complete in a single day - I can't see why you would take off the power steering pump or the alternator though access is tight but manageable with these items in place - Mike

Thanks for the replies.
Would I be correct in assuming

1) If the system had a blockage the emmisions would be up, and enough to fail the MOT ?? ( the car recently sailed the emmisions test on the MOT)

2) Even if the system were clear, the "oil trap container" would be filling, and if not "full" after 220K miles will be close?

3) Can the container be emptied and recycled along with old engine oils?

Cheers

Bob

In normal use the blow-by gasses from the cylinder head enter the catch tank in to one of the top connections, the oil droplets are separated and the gasses expelled from another connection on the top of the tank, the oil then drains down through a third connection on the tank back in to the engine sump.
Blow-by gasses from the crankcase enter the tank via it's fourth connection and again oil droplets are separated and returned to the sump with the blow-by gasses expelled from the top of the tank and returned to the air inlet to be burnt off in subsequent cycles of the engine.

As happened to my engine the lower oil drain port can become blocked causing the tank to fill up, once full it can no longer carry out its job so you do end up burning oil (1L per 100 miles in my case). Unless the oil drain return port is blocked the tank cannot fill up, it might have a little sludge in it at high mileage so worth changing once you have got to it as they only cost £20

If you are thinking about cleaning this lot out make sure you get the two small rubber hoses which connect the tank to the engine block (about £3,50 each) and I would get a new hose from the tank to the top of the cylinder head and a selection of Jubilee clips as you will have to cut off the original crimp type clamps Volvo used when assembling the engine.

The important part about cleaning this lot out is to connect a 5/8" diameter hose to the lower port in the engine block where the tank connects to, blow down the other end of the hose with the oil filler cap removed and listen for bubbling from the sump (you can hear it easier with the filler cap removed), if it bubbles and you can blow through it the port is clear, if you can't blow through it then it is blocked and you need to take further steps to unblock it before re-building the system - Mike - Mike

Many thanks for the reply mike.
Have been out this morning playing after finding out Volvo test the system by attaching a vacuum gauge to the dip stick hole.

If the value is less the -0.2kPa the system needs investigation.

Not having such a fine vacuum gauge, my DIY solution was a "U tube" fastened to a wood and part filled with dyed water.

From the Web 0.2kPa is equivalent to 0.8" water gauge.

Checked the T5 at "normal temp" and got -0.4" not as good as I hope, but still a vacuum.

Checked the AWD R again at normal temp and got -1.8" over twice the min vacuum level.

As I don't like to mess with things unless they are broke and in view of the high mileage, think I'll leave well alone, until I have to go in there to fix something else, at which time it might be time to say fairwell.

Cheers

Bob