I emptied the oil to check, the oil looked fine.
I have refilled with 10w40 also a different brand as the mechanic shop used a brand I was not able to get my hands on and changed the oil filter.

Coolant level seems to be constant.
The glove PCV test failed, what parts will I need to fix this on a Volvo 850, 1995, 20v, 170hk, petrol, non-turbo?

The engine also makes a ticking sound, I suspect it is due to a failed lifter.
I also plan on changing the head gasket just in case.

 

Welcome to VF soppen

Buying the PCV kit and replacing the components is one way to go. You can pull the hoses and check each one to make sure they are clear and that vacuum is actually getting to the PCV. You can try to rinse out the PCV and reuse it as it's not a complicated valve just a big box so to speak. Inside the PCV: The worst cause of the system failing is a clog in the block from years of build up. That's really hard to fix.

https://www.matthewsvolvosite.com/fo...hp?f=1&t=28487

When I first got my 850 I did the whole system. This is the one I used but there are other sources too. https://www.ipdusa.com/products/1126...24712-9471644k
https://www.ipdusa.com/catalog.asp?n...EARCHWORDS=pcv

Roberts DIY on PVC


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build up in the block is the main problem to avoid. If you are going to the trouble of lifting the intake manifold to get to the PCV tubing and oil separator, best to take the time to rod out the ports. You can also consider doing a Seafoam treatment prior to the work to see if that can loosen some of the gunk. If you are planning on keeping the car for a long time, you may also want to consider dropping the oil pan and cleaning the gunk out from the bottom end as well (plus a good time to replace the oil pump o-rings). The risk of not doing this right is that you can spend $600 on parts and labor only to find your crankcase pressure is still too high - which will eventually turn the engine into a bleeder and can push out the seals as well (usually cam seals but even that's a PITA)

 

Prior to complete pcv change add seafoam straight down the vent tube that connects into the crankcase. Let that run in there a bit. Then drain oil. Do complete pcv kit and rod out those ports. Then fresh oil.