Racor CCV

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I’ve never been happy with the RACOR CCV (Closed Crankcase Ventilation) system on our Deere engine so I decided to dig in and learn more. To meet emission requirements, the CCV (the black housing circled above) separates oil from the crankcase vapors, drains the oil back to the sump and sends the vapors back to the engine air intake. The CCV filter needs excessively frequent changes and, if allowed to plug up, will cause positive crankcase pressure which will lead to nuisance oil leaks. The RACOR system has a red “needs changing” indicator in the top, but I have never seen it pop-up, even when the crankcase pressure is far above the Deere maximum measured using a manometer.

I took the CCV apart to better understand how it works and see why the “it’s plugged” indicator never triggers. What I found was surprisingly complex for what should be a simple device. Crankcase vapors are vented into the middle of the filter and flow to the outside and then back to the engine. Normally I would prefer to see the vapors flowing through the filter from the outside inwards for more surface area, but that’s not the design.  There is a valve in the top that will vent positive pressure and bypass the filter. This sounds good but, in playing around with the system, it will not bypass until the crankcase pressures are very high. It looks like that indicator can’t be relied upon.

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The same valve at the top of the CCV can be pulled in the other direction to seal off the ventilation system when the air filter plugs to prevent excessively negative crankcase pressure. Venting crankcase vapors, removing oil from the air, and flowing it back to the engine intake really shouldn’t be this complex nor as prone to plugging. But this same system is used by Cat, Deere, Volvo, MAN, Cummins, Hercules, Mach and Detroit Diesel, so it appears that I am in the minority in not liking the design since RACOR has somehow managed to impress most of the world’s marine engineers.

One thing I noticed when looking through the details on the filter assembly is that RACOR supplies three different filters elements for this unit: 1) medium density (CCV55248-04), 2) high density (CCV55248-06), and 3) ultra density (CCV55248-08). The Deere part number , RE502284, cross-references to ultra density. In fact, all the OEM filters cross-reference to the high density (CCV55248-08) filters and, as a consequence, I couldn’t find the low density element where we currently are in the UK.  My plan is to switch from  CCV55248-08 to CCV55248-04 and, in the interim while still using the ultra density CCV55248-08, to change them frequently.

Another interesting option is the Wix WS10114. It’s a drop-in replacement element marketed as a racing filter. It appears to be very low density and a much nicer design that is less prone to clogging and causing nuisance engine oil leaks:


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20 comments on “Racor CCV
  1. Stewart says:

    Hi James, quick question on this thread as I am considering a retrofit with a cummins CCV as fitted on your engine. What cummins partnumber is your CCV filter housing?

    Thanks! Stewart

  2. James, did you ever fit the low density filter?

    • Hey Steve. Good hearing from you. Yes, I did install the Wix racing filter with the higher flow metal element. It’s been in there for 639 hours and it’s not plugging or causing excess back pressure yet. So, pretty good my that measure. I do notice that there is more oil making it to the aftercooler and there is some oil leaving the aftercooler drain. With the stock high density filters, there was almost no oil at the aftercooler. Overall, the new filter looks like it might be an overall win — they certainly last longer.

  3. Danko says:

    Also,on this engine CCV filter is installed too high,it should be lower then rocker arm cover,so that oil always drain from that hose that comes to filter.

    • The “filter” is only to demist the air leaving the crankcase so that it can be brought back into the intake to be burned without the increased pollution caused by burning oil residue. All oil removed by the AirSep is returned to the engine. The drain back is part of the design and the oil that doesn’t drain back in through the intake hose will be drained back down the oil drain hose to the sump. Either way, the oil is returning to the engine.

  4. Larry Martin says:


    I’ve had to dig the goo out of the intake tract of a couple of cars. The only effective way of cleaning it was removal from the engine and soaking. The EGR systems on many engines pass far too much oil back to pollute the intake, stick on the backsides of valves and coke the the rings over time. Enough so that blowby increases and oil consumption goes up further yet. I’ve got a Buick SUV right now that is doing exactly that. The best short term solution may be from the racing past James – catch can. Just a thought.

    • Yeah, those systems work fine and I did do that on our last engines, a pair of Cummins B-series and it worked fine. It can put a thin oily residue on everything and, on our current boat, a lot of air is brought through the engine room and it needs to be wiped down frequently. With a bit of oil that would go from a quick “wipe off” to a bit more stubborn so I prefer to send the blow by gasses back into the intake system. The engine doesn’t leak much at the rings so there isn’t much to get recirculated but, you are right that as an engine ages and blow by increases, this can cause build up in the aftercooler, on the turbo, and if it’s really bad, on valves and rings. My next try will be the Wix WS10114 or the most open of the Racor filters. If that doesn’t do what I want, I’ll fall back to the catch can.

      • Larry Martin says:

        In some of the latest classes I am led to understand that all emissions controls are to be “functional”. So some of the later catch cans are not “breathers” and shunt heavier oil particles into the can while still allowing the EGR gases by. If that is correct the oil fog issue from the old days may have been mitigated. I do note that the cans now range in price to beyond $1,000 which is still quite reasonable if it’s needed.

        To show how esoteric some of these oil/EGR issues can be I finally tracked the problem on the aluminum LM-4 350 in my vehicle to the EGR circuit in the valve cover. The location and shape (round, no lip) of the outlet from the head was apparently where the constant cruising speed (say 75 or so) RPM set up a harmonic that held oil there and the lack of a lip presented no obstacle. The solution was relocation of the opening, changing the opening to square and with a lip on all four sides. GM made that change three years later but failed to tell anyone. I suspect that way they wouldn’t have to outright say there had been an oil consumption problem in the first place. At least it also solved the mystery of why the oil consumption went up on long highway trips as opposed to stop and go where you might otherwise have expected it. So I have a new left valve cover for installation when I get a roundtuit. Unfortunately with 130,000 already on it there appears to have been localized wear on one or more cylinder walls where hardened crud was scraping so it’s always going to let some by now. I can live with it till it’s gone!

        Cheers sir and safe travels.

        • Exactly. That is what the design of the Racor CCV is attempting to deliver. They want to pull all oil vapors out of the air and let the clean air pass through while draining the remainder of the oil that is collected from the air back into the tank. The Racor design is to use a filter that the air can get through but the oil can’t and this works incredibly well. In fact, I’m sure the reason they have every major engine builder as an customer is the system works very well in a test cell. However, in actual use the filters plug up too quickly. Racor knows this and produced three different filters for them where the finest will plug very fast but really cleans the air well. As they go to less and less fine filters, the air gets slightly less clear of oil but the filters last much longer. I suspect that dropping down from the finest element (used by all the major OEMs since what engineer wouldn’t want as close to the most oil free air possible) and move own to the courses filter will yield both clean air being sent to the engine intake and long lasting filters. I plan to give it a try and see what we learn.

          • Larry Martin says:

            Looking at your photograph of the CCV device the thought occurs that it’s a shame they didn’t use some sort of simple spinning inertial separator. Wouldn’t have to spin very hard to sep oil from air, could probably even be low powered electrical. As you said earlier (paraphrased), they all use the current system because it works on a test stand. I would add to that, “and it’s cheap”.

            Fair skies.

            • I agree. Even a simple centrifuge would work great. My guess and I’ll try it later in the year, is the existing system with a much more open filter will also do pretty well.

  5. James:

    I’d be interested to hear how the low density filters works out. I’m a fan of the Racor CCV, I’ve had very good experience with them in both new and retrofit applications, however, I’ve only ever used the OEM filter, I’m intrigued by the low density version. BTW, I have seen the button pop…

    • On the button pop, I’ve seen manifold pressures at 2x Deere spec and still no popped button. When the valve is pulled up far enough to bypass, pressures are high enough to cause oil leaks.

      I’m optimistic about the low density filter option. I think it has a good shot at reducing the problem. Unfortunately, I won’t likely get one until I’m back in the US this summer. I’ll let you know how it goes Steve.

  6. Steven Coleman says:

    As far as I’m concerned, this is the next best thing since buttered bread. https://www.fastenal.com/products/details/0121782 If you want a higher temperature range, they have that too. I keep a 50ML tube on the truck at all times.

  7. Murray Birch N6303 says:


    Please explain your comment about nuisance oil leaks – where? I, too, have been waiting for the red indicator to pop up but it never does. Maybe I should change more frequently. How often do you change filters?

    Thanks for the heads-up.


    • I developed a leak at the oil pan that continues. I had leaks at the rocker covers and the rocker carrier to head gasket both of which I just changed when I did the injector job a couple of months back. I’ve heard reports of rear main oil seals caused by this issue as well although mine seems to now be dry.

      I’ve now gone to a rapid change model for these until I use up my ultra density filters after which I’ll move to low density or the Wix filter. I’m not yet sure which way I’ll go between those two at this point.

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