Hi,

I noticed that a previous owner had cut the vacuum hose leading from the oil trap to the fire trap - runs along the manifold next to the valve cover (presumably to offset the pressure buildup from the blocked fire trap, but now exhaust and oil leak from here). I am replacing my own fire trap this weekend (I hope... the volvospeed instructions look pretty easy).

So I stopped off at the dealer and they had the hose and said it should be pretty easy to replace and that if I plan to do the fire trap myself I was "doing the hard part". Well I can't even see where the vacuum hose runs. Does anyone know where I can find helpful diagrams and instructions for this? I have a Haynes manual but I can't find anything in there. It's a 1994 850 non-turbo.

Thanks in advance for any advice or help, I'm a newbie at home-repairs!

This hose can go to the side of the manifold as shown on a photo
on Bay 13, then it's fairly easy.

On my motor it goes to an oil canister that is *beneath* the intake
manifold, so the manifold has to be dismantled. It took me 6-7 hours
to replace the hose! (The power improved when I did.)

Dmitri

Dmitri,

I've been trying to diagnose suspected crankcase pressure buildup on my '93 850 GLT. Please elaborate on your experiences.

What is this oil canister. I've been told there is a pcv box under the intake manifold that is probably what you refer to.

Did you replace the vent hose from the block (pcv box) to the flame trap and did it make a difference?

Did you use a different part than was original to the car. (I've found out there is a recall on this hose - service campaign 69 A &/or B.)

Anyway I'm leaking oil everywhere.

Mark

Mark,

Sorry, I don't know what PCV box is :) The hose leads to
what is referred to in Haynes as oil separator. With a flash
light I could see that the rubber elbow that connects the hose
to the canister was broken. In fact I could pull the hose out
from its hole between the branches of the manifold.

I bought a Volvo replacement rubber elbows from the dealer
(they are made more robust now) and had a full scale war with
the intake manifold! I would say that it felt like extra 10 hp
after that (N/A engine). Also, the idle became more stable
(it hadn't got all stable until I changed a lot of other
stuff).

Dmitri

It sounds like this is what I have to do - they called it the "oil trap" and the other end is the flame trap. My hise was actually cut! I have bought a hose joiner which may be a better solution for me than trying to replace the whole hose as it sounds hard.

Could you describe the process of taking off the manifold and replacing the hose? Or perhaps this is just over my head...

-Tina

Yes, this is the oil trap, and it is under the intake manifold,
and yes, the hose on your photo is the hose in question.

To remove the intake manifold, you have to remove the fan,
release and move aside the fuel lines with fuel injectors,
and then unscrew all the bolts that hold the manifold in place,
and that's the hardest part. I think a flexible bit holder
will make it easier for the last bolt (passenger side) that
I had to unscrew with a ring wrench. Basically, follow Haynes
but do not remove the throttle housing and gas wire because
this is not necessary. You will need a new gasket for the manifold.
When putting the manifold in place, start tightening the bolts
from the center to the sides. Allow 8 [!] hours for the job.

The hose itself is just hard plastic with two rubber elbows
on the ends, very easy to put on and off.

Dmitri

Jeeeeezzzzz, I'm gonna check this out on my car!!. What prompted you to check this. Were you leaking oil or was it the rough idle?

I tried to follow that tube but could not see where it went. I appear to have a rear main seal leak, but could this be it instead??

Mark

It was rough idle. I saw and replaced the rotten elbow on the flame trap end
and could not help wondering about the other end. If the seal already leaks,
I guess you'll have to replace it; but holes in this hose would rather ease
the pressure than increase it.

Dmitri