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(Post Link) post #1 of 3 Old 23-02-14 Thread Starter
Status: 159 Cruiser and Guilietta pocket rocket
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Oil catch can, how to

Hi, just fitted my oil catch can today, so a bit of a how to, and discussion, (will edit with time to add more pic and info)

Difficulty rating 1-2 ( surprisingly easy, hardest part is getting your oil catch can set up with baffles)

Why you might want it:
The cylinders aren't 100% sealed, so some of the gases bypass the piston rings and get into the the crankcase, with the heat, some oil vapour can build up. In the past, they simply vented this to the atmosphere, but due to pollution regs this now gets sent back through the engine.
For the JTDm this oily gas gets put in between the air filter/MAF and the turbo, so coats the turbo, inter cooler, pipes and manifold (where it creates a gunk with the EGR soot). It then gets burnt in the cylinder with the diesel (where it's different burn characteristics create uneven burn and soot). The JTDm does have a type of separator, but this still lets a lot of gas back round ( as can be seen by the smokey gas it releases).

What you need:

Oil catch can.
Jubilee clips
Flexible silicon tube ( I used with 16mm inner diameter), and about 2m worth.

How To:
  • First, prepare your oil catch can if needed (as many are hollow). I got a cheap one off e-bay like this one , try and make sure you get the 15mm fittings on it (and possibly a smaller can than this one as it is a tight squeeze), unfortunately as the cheaper ones are hollow inside, it's best to fit some baffles:

    I made a feed pipe from 12mm metal tubing to take the gas to the bottom of the can (see picture), with holes down the side as when the can fills with oil it will need another route out, I then put some metal kitchen scourer ( not steel wool, which may corrode) inside. So the oily air comes into the catch can, down the pipe, and then should diffuse through the scourer (baffle), and condensate out. (this it what it should look like). This was the most difficult part of the operation (I used 12mm Outer dia tube), so it fits in nicely to the 15mm inlet fittings.

    There are some ready made varieties with baffles in. Be warned, too much scourer ( or your choice of baffle) could create too much back pressure and is to be avoided.

  • Remove the clips on the tube from the air intake, and to the one that exits from under the engine cover bottom left (it's a U-shaped pipe that connects them). You can see where they are on the 1.9 by following the red hoses in the picture below, (think they are at 90 deg to this in the 2.4!)Then remove the pipe, the clips are a nightmare to re-clip, so dispose of and use jubilee clips instead. (The pipe coming from under the engine cover was tough to get off, I slide a blunt blade under the rubber, and this loosened it enough to pull off)
  • Place the oil catch can in the engine bay. I found a spot just in front of the engine, just near the battery and front left headlight, I moved the coolant house slightly and it wedged in place ( not the ideal solution admittedly, but it's not moving at all) .
  • Take your silicon hose and fit in position, from the pipe that goes under the engine cover to the catch can inlet (with the pipe I manufactured in), then another from the outlet to the air inlet pipe. You may want to cut in small notches (as per the original pipe) too.

    NOTE: It is important to trim to the correct length, I found if too long it could kink (and cause back pressure and smoke), or get pushed by the bonnet when shut ( and again kink). Perhaps a slightly more sturdy hose, or re-inforced 45 deg bend would prevent this?

I've only had the catch can on a little bit (25 miles), it drives well, but the gasket on the top of the can is letting a little gas/ smoke out on idle, so I've tightened the screws up, the can was definitely still letting gas through as it should, as when I kink the tube to the air intake the amount of smoke out the can gasket increases!

From this, it appears that on idle, without the turbo sucking in air, there is not much of a vacuum to pull the gas through, so if your baffle/ catch can is to restrictive you could get a build up of oily gas/ back pressure, which will reduce performance and could lead to issues and smoke.
Attached Images
File Type: jpg pipe.jpg (21.5 KB, 108 views)
File Type: jpg engine.jpg (97.6 KB, 279 views)

159 1.9JTDM Ti and Giulietta 2.0 Veloce
ex: Punto 55s, Golf Mk5 1.4FSi, A3 (8P) Sportback 2.0TDi SE, A4 (B8) 2.0TDI S-Line, 306 HDI Meridian

Last edited by giblets46; 25-02-14 at 11:09.
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would be good to see some pictures to make sense of the text.

Have you set it up so that your catch can vents to atmosphere then or have you get it so you've got the additional catch can and baffle in place and still linking to the intake?
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(Post Link) post #3 of 3 Old 24-02-14 Thread Starter
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It's got the baffles, then back into the turbo inlet, hopefully remove some of the gunk before it heads back in.

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