Friends -

My 1990 740 16 valve B234F breather box underneath the flame trap is shot after 222,000 miles. A replacement unit (Volvo PN 1326252) is unobtanium.

This lovely schematic shows my set up.
https://www.volvopartswebstore.com/showAssembly.aspx?ukey_assembly=235417&ukey_product=1126534#1

I am looking to find a solution. Some have told me to carefully remove the breather box and attempt to clean it. I'm skeptical. But I have to do something.

Any thoughts? Any other sort of system that could replace the PCV system on this set up? It seems my 16 valve is the last one on the east coast...

FOLLOW UP -

Thanks to all for your suggestions.

I did try IPD, dealers, VCOA ads in the back of ROLLING, to try to track down the part etc. Noone has the part. It has been unavailable for a very long time.

So after much debate, my mechanic and I agreed to attempt a refurbishment. I bought all of the parts available for a redo - mostly o-rings and small rubber parts - also new manifold gasket. We soaked the breather box in cleaning fluid and after working at it, we were able to clean it up relatively well.

Car runs better than it has in a long time. Much less likely to stall out. But I still haven't completely figured out the stalling issue - cleaned the throttle body, but it still tends to stall out at stop lights, especially when its 85 degrees plus outside. But the breather box is fixed!

Good for you, knew you could do it with a few o-rings and bit of patience.

As for chronic idle/stalling with a B234F, well I'll tell you right now you have my sympathy as they are indeed more sensitive to such problems than the other red blocks. As much as anything, idle/stalling problems with my B234F are what first brought me here to the brickboard well over 20 years ago now.

I'll start off with a few B234F specific thoughts for you that can affect smooth idling on the ignition side. Make sure there's no oil down in any of the spark plug recesses from the inner area of the valve cover leaking so that oil vapour doesn't foul ignition wires. Make sure the ignition wires are in good clean shape, solidly on the plugs and in the distributor cap and coil, replace as needed. Keep underneath the plug cover plate clean. Most importantly, make sure the plugs are in good shape. On the B234F (geared with the AW72L and different rear end ratio) during lots of low rev city driving the plugs will more easily foul. Cruising along at 1600 rpm isn't what these engines enjoy. Using nothing but high octane gas with premium additives definitely helps -something cheap people like me have problems adopting. If giving it a high revving Italian Tuneup makes a significant difference for a few weeks then concentrate on fouled/worn plugs as being an issue. I found switching to a slightly hotter spark plug reduced fouling for me as I did mostly city driving at the time. The early production 1989 coils used with the B234F were also known to be a bit weak that created spark problems, but by 1990 yours should not be an issue.

Now on the intake side, and this is where you're likely to find actual stalling issues, make sure the entire intake and PCV side is kept scrupulously clean, no vacuum leaks and everything is adjusted to spec. Beyond spark plug fouling, a lot of my idle/stalling issues were related to a dirty throttle body and incorrect adjustments (some were my fault, trying to raise the base idle to get above a rough idle). A dirty/sticky/worn IAC valve makes for a bigger issue with these more sensitive engines. The Volvo specs for the B234F throttle linkage adjustment are actually slightly different from the ones you'll see here and elsewhere for the B230F/FT, but the principles are exactly the same and the specs are close enough for practical purposes.

If you're interested in a recent discussion I've had here on idle/stalling issues and throttle bodies, you may want to check out this thread for more hints TPS Sensor test 700
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

I sympathize with you on this. I was recently trying to find a tail-light circuit board for a sedan, and it's not listed in most places.

I imagine that Yoshifab might have something, or an interest in making up something, to cover this for the b234f.

The b234f boxes might be more robust than the b230 boxes, but I wonder what you mean by shot - is it split in half at the seams?

Have you called IPD or a local dealership?

I note there are three o-rings used on the B234F oil separator box rather then just the one o-ring used on the B230F/FT oil separators. It will be best to replace all three to ensure a tight seal, definitely replace any that are no longer plump, soft and pliable.

Referring to your parts schematic they are p/n's 949659 (34mm i.d.), 968599 (13mm i.d.), and 949656 (19mm i.d.)

All appear to be currently available, even in the aftermarket, and some may well be in local dealer stock. In addition to PCV oil separator boxes, you will find some of those listed for other Volvo applications, such as distributor shaft seals, power steering seal, manual trans shift lever seal, ZF power steering rack seal and trans speedometer sensor seal.

As much as you might want to try using commonly available everyday neoprene rubber o-rings, you should be using a more oil proof and more heat tolerant Buna-N or Nitrile type of o-ring. They are often green or brown. If you get aftermarket ones that are black you may not know what they're made of, so probably best to avoid those.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Apparently you have determined that it is a different item than what is used on the B230F engines?

What do you mean when you say it is "shot"?

I have cleaned many of the oil separator boxes on the B230F engines. They are quite robust. I remove them and repeatedly strike the surface with a small hammer. The opening on the top can be reamed with a 3/8" twist bit.

After loosening all I can with the hammer I shake out what has been knocked loose and then soak the interior with gasoline. Then it gets a good rinse before reinstalling it.

I have read here several times that the aftermarket replacement units are absolute junk and are prone to fail at the seams.

Good luck,
Randy
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Any twenty minute job is just a broken bolt away from a three day ordeal

Every single one I've ever seen splits at the seam on the outside and sprays oil onto the engine block. I've cleaned one that was OEM, which split a few months later.

Now I just replace them.

Where do you source replacements?
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Any twenty minute job is just a broken bolt away from a three day ordeal

I was surprised this is NLA even in the aftermarket, but as a former B234F owner I was even more surprised to learn it was different from the other red block oil traps, yet it appears you're right. If it's built as solid as the other Genuine Volvo red block oil traps then I agree with others that there's a very, very good chance you can remove and clean it without breaking it. All you'll likely need is a new o-ring, which as I vaguely recall is the same as the distributor o-ring and commonly available. In the past I've had an aftermarket new oil trap standing by so that when I removed an old one and tried to clean it I would have a spare, but I've never had a problem. Once you've got it safely out of the block everything is downhill doing a bunch of flushing with something like paint solvent while you semi-carefully rod out some of the cake. You don't have to get everything, just enough to get it to breath properly for another 10 or 20 years. Good luck.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now