How To install a oil catch can

August 27, 2019


Modern cars have to be conform with emission regulations. When an engine operates it creates a little bit of pressure, you dont want this pressure building up inside of the engine. So what they do is take this pressure and feed it trough the air intake, back into the engine. This air as vapourised oil in it, when it gets recirculatd in the engine it creates a whole list of issues in the long run.

At one point i started to notice that my engine wasnt as powerfull as it used to be, my sprinter started to consume more diesel than usual aswell. When i got the issue fixed, i talked to the mechanic and he told me that the issue was related to the pressure being recirculated to the air intake and that a catch catch would prevent the same issue in the future. So i installed a catch can!


These are the parts that i used:

  • Oil catch can
  • Copper tube (size of the inside of the catch can fitting)
  • Steel whool spunge
  • Plastic tube 18mm and 25mm (depends on you connector size
  • Plastic reducers (to go from 25 to 18mm)
  • Hose clamps


There are many different catch cans, you can choose the cheaper route but these do not work as efficiently as the more expensive ones. The one i bought is a cheap version but i modified it so that it should work better.

The cheaper versions do not come with an internal filtering system. With these you run the risk that the oil will get sucked back in without staying in the catch can. Which makes it just a longer circuit with a pot in it. so i modded mine.

In the first picture you can see that i added copper piping to the hose connector. This way i make sure that the oil wont be sucked straight back into the tubes. Now the oil will be forced down. After that i put a steelwhool spunge over the copper pipe to make sure that the oil stays down. Close the catch can again and prepare for the installation. I placed mine next to the cabin filter, perfect open spot!

First we have to locate the engine over pressure hose connection from the engine to the air inlet. In my case it looks like this:

First step is to remove this tube, make sure you leave the sensor in place. This tube is fixed in position very firmly so some elbow grease is needed. As you can see on the image below, the tube connector is quite greasy. You should clean this connector.

With the standard hose off its time to make the custom tubes. start with the 26mm tube and cut it half the length of where your catch can is located. The other half of the tube will be the 18mm one. Place the reducing coupling in the tubes and make sure they are firm in place. If the tube feels loose you can use a hose clamp or a zip-tie. Because this is low pressure it is not that big of a deal.

Repeat this for the other side of the catch can. The other side of the hose has to go to the sensor. We want to make sure nu errors will pop up in the system. Check if all the hoses are firmly in place. The oil will make the connector slippery so make sure to clean it first.

Make sure the hoses stay in place so tighten them with zip-ties to the engine air intake. In the end this will be the result:

Now all the oil vapor that normally would get sucked back in the engine will be filtered in the catch can. Now not 100% of the oil will be filtered, there always will be some oil that gets sucked in but its in a much less percentage.

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