Back in June 2018 I fitted a Man HummelProVent oil catch can to our Amarok. Since then I’ve had a few people asking me how we have been getting on with it and has it actually ‘caught’ anything.
I fitted the ProVent to our VW Amarok when it had done about 8000 miles (12,800Km) and we have now done just over 13,000 miles (21,000Km) a great deal of it towing. I opted initially to drain the ProVent every 600 Miles (1000Km) and the first three each time I got about half a cup of slightly oily water. It was clear like water but when rubbed between your fingers it felt ‘slippy’ a bit like baby oil. I did notice that one draining that covered two long tows up to the Lake District what came out was slightly darker, still about the same quantity though. However I did notice on the last draining I had more of a dark oil content as a separate layer in the lighter clear ‘oily water’. Watching the video below I did find out that this is normal. The filter that is in the ProVent takes a few hundred Km to start working properly, first catching the condensate and then once the filter is saturated does it start to catch and drain the heavy oil.
I did recently remove the hoses on the intercooler (inlet and outlet) just out of curiosity and the interior from what I could see was still clean, with only a light covering deposited from the first 8000 miles (13,000Km) of running without a catch can fitted.
So how much have I got out?
Well in the first 5000 miles (8000Km) I have now filled an old 500ml 2 stroke oil container and just started on my second. I’ll continue to drain at the 600 mile mark. Although I must admit I now drain it before a long towing trip and again when I return home. It only takes about a minute and doesn’t require any tools so really is one of those tasks that is easily accomplished with the minimal of effort. Hopefully this will keep our engine in tip-top condition and not start to suffer from the oily carbon build up that saps power and is prevalent in all diesel engines.
Here’s an excellent video from the guy’s at 4WD Actionwith probably the best explanation I’ve seen so far on the net… (Video (c) 4WDAction.AU)
After a quick four-day break at the Caravan & Motorhome Club’s site at Wirral Country Park (excellent by the way… already trying to work out when we can go back!!) and a bit of work getting in the way it was time to get going again not he catch can… really it should be called the “Air Oil Separator” Install.
Last time, I’d decided if IKB would have been shaking his head… then it wasn’t right. I decided to make a new bracket out of 1.8mm aluminium sheet and go into full on origami mode. (ps.. after the last post someone emailed me asking what IKB was…. Mr Brunel was not pleased).
I wanted to make a bracket that passed under the air con pipe and bonnet cable release fitting so that it cleared everything and gave good access at the same time. As a test I did a trial bend if some 1mm thick steel I had just to get the shape…
Once I’d got the angles and size sorted it was time to move on to the aluminium sheet. My press brake… well I call it a press brake, in reality its a cheap basic hand folding machine but it works very well as long as you know its limits and don’t get daft trying to fold big stuff. It was all about the angles…
The first two were easy and I could form the lip with two folds, the second was less than 90 degrees so I just about got away with enough clearance. However folding the return that would lip over the front cross brace which was also less than 90 degrees also meant that I’d have a problem fitting it in the folder.
However, a little lateral thinking and taking the blade off the folding machine, inserting my workpiece and re-installing the blade meant I could fold in the opposite direction (downward)… result!
A quick trim and rounding off the edges gave me a rough folded bracket. A quick file of the edges and work-over with some fine emery removed all the tool marks… quickly followed up with a coat of etch prime to protect it.
I now had to work out how to mount the plastic housing the bonnet release cables were located in. On the rear of the fitting were two plastic tabs that locked into two square holes punched into the vehicles cross member.
So a few minutes spent with a dremmel and a couple of suitable sized swiss files later…
… and the piece was ready for a final rub over with scotch bright a second coat of etch primer and two coats of black.
The Installation…
All went a bit easy actually… which is flipping’ unusual for me. I released the bonnet (or ‘hood’ for my American friends) cable fitting and simply clipped it back in to the two new holes I’d made.
The Provent was installed next…
… again without any issues. Next was to sort out the plumbing.
I’d done a bit of research and asking around and the guys at ASH… AutoSiliconHose.comhad come highly recommended. So a road trip over the Pennines to Mirfield (just east of Brighouse in West Yorkshire) was scheduled.
I had a basic list of what I thought I’d need and the chap behind the counter hooked me up with everything… including the alloy couplers he cut to size while I waited. Great service from ASH and I can definitely recommend them.
Back home with my shopping, it was time to start on the plumbing.
For securing pipes, I personally prefer spring clips… the type you install with special pillars, however the silicon hose OD was slightly too large for may normal stock of clamps so I had to opt for using the wire type. I’ll order some of the correct size and replace the wire clamps as soon as they arrive.
It was really simple now to just assemble the bits, cutting the silicon pipe to length as required. I used a pair of plastic conduit cutters to easily slice through the pipe.
Before I made the final connections to the crank case breather port or the turbo inlet port I blew the pipes clear using a high pressure air line.
All that was left to do was install the drain hose, one way valve and drain tap. I used normal 20mm oil line for the drain, inserting the one way valve about three inches below the outlet of the Provent catch can. The remainder of the hose was dropped down to chassis level and the drain tap added and secured with a couple of zip ties.
The Finale…
I secured the pipes in a couple of places with zip ties, now I know the route I can make a small stand-off bracket with two rubber lines “P” clips to mount on the engine to hold the pipes, although they are self-supporting because of the short length.
In the photographs above it looks like the piping is tight across the engine, I did do a pull and push test and there is plenty of movement at the 90 degree bends to allow the torque twist of the engine without pulling or pushing on the pipes at the catch can end.
The current mileage is 11,750 or there abouts, so I’ll check the drain and filter in 100 miles and each 100 miles after that so I can get an idea of how the setup is going. I’m not sure how long the filter is designed to last, but Ill put it on the schedule to replace ever main service. The other thing that is an unknown is how much oil I’ll get. I have been watching some YouTube videos made by Berrima Diesel in Australia (if you watch any of the Australian 4 x 4 or off-road channels you will recognise the name). I only found out about their catch can experience when one of the guys from one of the 4 x 4 adventure channels got in touch… even if you don’t think you need a catch can but drive a big diesel their videos are well worth watching.
Ok… I was saying I don’t know how much oil to expect… but it did surprise me that Berrima Diesels posted a video showing a new 4 x 4 with about 6000Km on the clock had produced about 300ml’s of oil using the same Provent catch can. It’s also worth taking look at what the have to say about the current oil specified in diesel engines.
The other thing I noticed was when I left the engine ticking over for about ten minutes. Bearing in mind I had just come back from West Yorkshire via the M62 and M60 and started the pipe install as soon as I got back so the engine was still hot, the difference in temperature between the short length of pipe exiting the crankcase vent and the inlet pipe of the turbo. The pipe exiting the crankcase vent port was almost at the temperature I could not keep my fingers on it, while the inlet pipe I’d connected too was still cool. I’ll have to get my thermomiterbob laser do-hicky out and get some readings… but anything that helps cool gasses going into the turbo has to be of benefit right?
That’s it for now, I know it’s not caravanning related that much… unless you want to get the best out of your diesel while towing. I promise the next one will be caravan related, honest!
As in part one I’d also like to give a shout out to Charles at HumbleMechanic.com for all the information and videos he produces about VW vehicles. Charles has been an absolute gold mine of information for all things VW and if you drive any of VW’s vehicles please be sure to drop in on his YouTube channel and take a look.
I’m installing a “Catch Can” can on our VW Amarok and this little posting is all about it, but first a bit of history on why I’m installing one.
If you look at modern high performance diesel engines one of the things that they do to reduce emissions is have a number of systems to reduce the harmful emissions. EGR or Exhaust Gas Re-circulation wich is feeding part of the engines exhaust back into the intake but probably the most widely known is the DPF… or Diesel Particulate Filter which captures fine soot particles from exiting the exhaust. The DPF needs to be cleaned regularly, through a process called regeneration. Either active, passive or forced, the accumulated soot is burnt off at high temperature (around 600°c) to leave only a residue of ash, effectively renewing or regenerating the filter, ready to take on more pollution from the engine. To regenerate, the vehicle electronics adjust the timing of the engine to increase the exhaust gas temperatures or commonly it can be achieved by passive regeneration usually on the motorway when exhaust gasses are generally hotter.
In city driving or short trips the regeneration my not take place fully, leading to blocking of the filter. This can lead to higher fuel consumption and a visit to the mechanic for cleaning or replacement.
Forced Regeneration
If the DPF become blocked you will get an engine warning light and/or a DPF warning light to let you know that a regeneration or cleaning is required. If the vehicle continues to be driven and the engine load is not enough for the automatic process to be initiated you will get a second stage DPF warning. When your vehicle displays second stage DPF warning lights it will usually go in to ‘limp mode’ and should be taken to the dealer to ascertain the extent of the problem.
A forced regeneration involves the garage using a computer program to run the car, initiating a regeneration of the DPF. This will also usually require changing the engine oil & oil filter.
Why does my Diesel Particulate Filter (DPF) block
Problems arise around town with stop start driving where the regeneration process might not complete or the engine never get hot enough for a long period. A warning light will illuminate or a message indicating the DPF is full displays on the dash. If you continue to drive in the same manner, the soot build up will increase until other warning lights illuminate and the vehicle will go into ‘limp’ mode, where driving speed is restricted.
Crankcase Ventilation
In all piston engines a certain amount of ‘blow by’ happens, this is some of the hot gasses treated in the cylinder combustion leaking past the piston rings.. or ‘blowing by’ and entering the crank case in the sump area. This pressure needs to be released and twenty years ago the engine oil filler cap used to have e vent in it. However in modern emission controlled vehicles this is not acceptable and the excess pressure is vented into the air intake of the engine where it passes through the engine cycle and exits through the exhaust. These hot gasses passing through the sump on their way out pickup fine mist of oil from the sump which is carried through to the intake of the engine and this creates three problems. The first is a sticky residue build up on the intake valves that hardens with temperature – especially on direct injected engines. Secondly the intake pathway gets coated in oil from the engine. If you have a turbo charged engine with an intercooler, this can become an issue as it reduces the heat exchanging effects of the intercooler. Thirdly, when the oil is burnt in the engine it creates a heavy soot that increases the build up in the DPF.
When towing, you generally use more power for accelerating and maintaining speed which is great in one respect for the DPF. The downside though is the piston blow by is more and therefore the crank case pressure is increased.. picking up more of that fine oil mist from the sump.
Now the diesel engine tuning guys and the 4 x 4 guys in Australia have known about this for a number of years and they have a solution to the problem.
Cleaning up the crank cases gasses – “Catch Can’ or Air Oil Separator?
There is a difference. a ‘Catch Can’ is usually just that. A can that the gasses are fed into with an outlet that is fed back into the turbo inlet. Some do have some form of baffle but a lot don’t. More expensive ones may have a gauze wad inside for the oil droplets to form on. A lot don’t have a drain, you have to remove the bottom of the can to empty it. If you look on auction sites you can find nice looking anodised aluminium ones for £20 or £30 but for that sort of money all you are really paying for is the nice looking anodised aluminium. Not for an efficient effective unit.
On the other hand, a true Air Oil separator will have multiple traps in the form of differing size materials making up membranes for droplets to form on. A number of them are designed to swirl the gasses around first before exiting through the centre after passing through the filter membranes.
I wanted to get as much oil out of the gasses before they enter the engine inlet. So I opted for an Air Oil separator with replaceable membrane filter rather than a cheap ‘catch can’. Seems like a simple device really, but there are a few more things to take into consideration…
I’ve opted to use the Mann-Hummel ProVent 200 on our VW Amarok. It’s been used all over the world with hundreds of installations on Toyota’s, VW’s, Mitsubishi’s, Land Rover’s and not just on 4 x 4’s.
My hope is that I’ll reduce the emissions through the engine while prolonging the life of the DPF, keeping the inlet clean and oil free and importantly preventing that soot and carbon buildup in the inlet ports and valves while maintaining the efficiency of the intercooler.
Getting Started
I did look at the kits available for the VW Amarok and all were sourced in Australia. However I could buy all the individual components in the UK a lot cheaper than importing a kit. Bit’s ordered, the first decision was where to locate the unit…
In the Amarok’s engine bay there is only two real places viable for the location of the ProVent. The first is on the back wall next to the engine ECU which seems to be the place of choice for most of the kits I’d found, and the second is in the front right hand corner in front of the battery.
Installing it on the rear firewall next to the ECU would mean partially covering up the Air Con gassing ports and I just knew that would be asking for trouble in the future…
So the location that in my mind seemed the most logical would be to mount it in front of the battery, manufacturing a suitable bracket to hang it off the front top cross-piece where there seemed plenty of room and easy access.
This would also allow the two pipes… one from the crank case pressure release port (left below) and the return to one of the turbo inlet ports (right below) could take a short route from the ProVent across the front of the engine and would give me a couple of suitable points to mount supports for the pipes.
I needed to manufacture a bracket that mounted to the top cross rail and went over the air-con hose and bonnet release cable just below it. As luck would have it in my scrap metal bin I had the chassis from on old bit of electrical kit that was made out of aluminium and looked like it would do the job.
Cutting a section off, filing down the edges and drilling mounting holes didn’t take too long and that was followed up by a coat of etch primer and a couple of coats of high temperature gloss black (I only used that as I had a spare can from a previous job!)
Fitting was fairly easy…. and no, they will not be the final bolts!
Marking and drilling three holes, followed by a couple of coats of metal protector to stop the edges of the holes rusting soon had the bracket in place. If you are wondering why the shape… well it came like that when I cut it off the scrap chassis, but quite by chance it allowed access to the hole which is access to the headlight adjuster screw.
Mounting the ProVent was now simple enough…
It was at this point I stopped. I didn’t like the way it covered the air-con pipe. There was little chance of it rubbing, the pipe already had a big rubber ring on it to stop chafing against the front cross beam or the bonnet release cable. I also now could not get to the bonnet release cable. The mount covered the point where there was a lubrication and connection block for it. It just wasn’t good engineering design. IKB would be shaking his head and wafting his cigar around in dissatisfaction..
Back to the bat cave. Time for a rethink and to hone my skills in sheet metal origami.
I would like to thank Charles at HumbleMechanic.com for all the information and videos he produces about VW vehicles. Charles has been an absolute gold mine of information for all things VW and if you drive any of VW’s vehicles please be sure to drop in on his YouTube channel and take a look.
Caravan Chronicles 