Hello Bricksters,

Thought I'd pass on my troubles and observations about the oil separator boxes that I've replaced.

After replacing a main seal on red sedan, I thought it prudent to clean out the PCV system from top to bottom including replacement of the oil separator box (rather than trying to clean it out). I ordered the so called OEM unit from FCP which I recently learned is not OEM. After about 6 months the horizontal seam split and I developed a substantial oil leak. Replaced the box with a Volvo unit about 1 year ago.

Green wagon. A moderate leak turned out to be the oil separator box (again aftermarket) that was replaced as part of PCV system cleanout. Again, the leak was at the horizontal seam. I replaced that box with a Volvo unit this afternoon.

Turns out the aftermarket units are solvent welded at that seam. Sort of like the "glue" used to connect PVC pipes. The Volvo units seem to be made of the same (I think High Density Polyehtylene) material, but the horizontal seam is heat formed. They must melt both sections and then slam them toghether cause a bunch of melted plastic is woven onto the outside of the box at the seam. Looks much more sturdy.

After my troubles, I would be leery of the aftermarket boxes, or if you develop a leak near the starter, I'd head straight for that box. You may want to test the watertightness of a new (or used) box like I did by just plugging the flame trap tube, filling it with water and look for leaks. My leaker had water coming out in a number of locations along that seam.


Marty Wolfson

Regarding he O-ring on the oil separator box, either mine was missing before or it was lost during removal, can I just bring the oil separator box to a local auto parts store and fit it with a stock o-ring or is the volvo specific o-ring necessary?

O'Reilly's Auto Parts has a huge box assorted O-rings and in a minute I was walking out w one that fit perfectly.

How do you know whether the unit you are buying is an OEM made unit or an after market unit? The part number 3501160 on alot of internet web sights sell it, and they all seem to claim theres is an OEM unit. They both look alike how would you be able to differataite between the two, so you knew what you where getting online. I only have 1 volvo dealer with in a 1/2 hour drive from my house, the next one is almost 100 miles away, and the one near my house seems to be padding the profit margin on there parts prices.

Hello 245 DogWaggin,

The part number for the box is 3501160 and the part number for the O-ring is 949649

The box was $35.34 and the O-ring was $2.98 w/o shipping at Tasca Volvo.

Marty

thanks Marty,
I had been looking up the part by name using the Tasca drill down menu but couldn't locate it.
It's amazing the stuff that comes up on their site when you acrually have part#'s to refer to!
~jason

I gave up on the whole separator box, flame trap system hassle, and installed a racecar style positive crankcase breather and catch tank. The half-gallon tank mounts by the carbon canister and only needs draining at oil change.

I might just be seeing the same issue with my 740 turbo.

Should have kept the original box!

Did you folks have to remove the intake manifold to get to the oil separator box? Or is there enough room under the intake manifold to get your hands in there to remove the box? Thanks.

Hello Fred,

I remove the throttle body and IAC along with the AMM and intake plumbing. You really don't have to touch the intake manifold.

Then removed the harness wrap-around which screws to the top of the box. You can deftly push the harness up then lift the box up til it's bottom protrusions clear the block and get it out.

I clean up the block mating surfaces and on reinstallation, I make sure I have a new O-ring ($3 part from Volvo!) and use some non hardening seal at the front hole.

Marty Wolfson

If this is done on an e.g.r. equipped vehicle. You will need to remove some piping that blocks the access for the bolts that hold down the oil separator box. The replacement of this part of the pcv system really is essential to engine longevity especially engine seals:). Have fun, and take your time.

I bought one of those from FCP, too. When it arrived I saw how it was glued together and decided against putting it on my car. I thought I might hang onto it in case I ever needed one, but after reading this post it's going back to FCP. Thanks for the info.

The May 2009 Popular Mechanics has a "Car Clinic" article on repairing plastic reservoirs by Mike Allen. He mentions coolant expansion tanks and windshield washer tanks. The technique uses the Permatex Plastic Tank Repair Kit, which is basically a fiberglass patch, sandpaper, and epoxy.

I don't know if it would work with oil separator boxes or other tanks, such as power steering fluid reservoirs. It might be worth a try, depending on the cost of the repair kit.

I do know I'm getting tired of replacing OEM power steering fluid reservoirs because of cracks at the seam. Next time I may try the Permatex.
--
1986 Volvo 245

I second everything you said! I'm on my third new oil separator box (all supposed oem from fcp), and judging by the amount of oil I just had to add last week, I think this one may have split as well.

Hi Marty
i had the so called oem fcp unit split on me.
ended up putting back the original.
on my car i have egr which makes the job that much more fun.
i have posted this in the past.
Mike

Thanks to you for taking the time to post your experiences with the aftermarket oil separators.

I do know that the orginal oil separators are very rugged items. Since I have a few parts cars I can be a little more aggresive in cleaning the original separators- if I break one I can find another. I haven't broken one yet.

I remove the separator and use a 3/8" drill to ream out the top opening. I then tap around the outside surfaces with a brass mallet I have. Blunt hammer face impacts on all the surfaces that are at least as big as the hammer face. This knocks loose a large amount of crude that has built up on the inside surfaces. After knocking it loose I shake it out of the openings until I can no longer hear any "rattles" from inside.

I then plug one opening and fill with gasoline. I let it soaks for as long as possible- overnight at the very least. Shake it occasionally. Drain the gasoline and fill it half full again with gasoline. Shake it for a goodly period of time before draining again.

Install a new Oring and the box is ready to be installed.

Randy

Marty,

I'll give you a thumbs up on this one as you are technically correct about the "heat" welding on the vertical seam. The actual process is called ultrasonic welding, ie. shake the crap out of both sides in opposite directions to allow friction to create heat. The parts truly weld together and bond on a polymer chain level... not just at the surface like "chemical/solvent" welding.

The joint itself is probably stronger than the rest of the part.

jorrell
--
92 245 250K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

As you said earlier: I learn something new everyday.