Catchcans

If they were really needed, do you think that Mazda would have already fitted one?

I think they are just another Must Have, same as Turbo Timers were a few years ago.

Cons - In my opinion they are a con.
300,000 on the clock and still pulls like a train. Mechanic quoted me 150-200 dollars to clean the inlet but told me it probably be a waste of his time and my money,

Dam, put it in the wrong place again,
Roy, the questions were for you mate.

Cracked pistons can't really be contributed to intake restrictions, the combustion mixture will remain the same on common rail engines so how does it over heat pistons.
The real killer on 1KDs is performance enhancers mixed with towing, trying to make a boy do man's work.
The build up in your engine is not caused by oil vapour, it is a mix of nice slippery oil vapour and nasty abrasive carbon exhaust particals. The answer is to get rid of one or the other, so why choose to get rid of an upper cylinder lubricant and keep the abrasive stuff, doesn't make sense to me.
There are a couple of ways to get rid or minimise the soot.
Can you please answer a question truthfully, was your car fitted with a throttle controller or have a performance tune?
And just out of curiosity, was cylinder #3 one of the cracked one?

I have fairly limited knowledge of diesel engine mechanics but there was a catchcan on my 2014 Pajero when I brought it.
I have noticed that the oil looks very clean on the dipstick between services unlike my previous Holden Rodeo, the new oil in it seemed to turn black immediately after oil changes.
When I first got the Pajero and checked the oil level I initially thought there was no oil on dipstick as it was as clean as when it came out of the bottle.
As stated I have limited mechanical knowledge but reckon clean oil has to be better for the longevity on my engine .

So if they are a waste of time and money why does Toyota now fit one to the 2.8 TD in the 70 series.
Then think of all the poor bods that fitted one over the years only to have Toyota deny warranty claims because one was fitted.

Berrima Diesel have for a long time been the gurus for Diesel engines, a family business in Berrima and now also in the Philippines. They have many YouTube vids on this subject and it may be worth a search to settle what is heresay and what is not on this subject.

From what I've read over the yrs they are a benefit in several ways no matter how minor it helps it can be a benefit like stopping oil coating the inside of the inter cooler which has an effect on it's cooling air. It can play up with the air fuel mixture and even add to build up in the intake also helps to remove any contamination like condensation that might be present in the blow by oil vapour.
So lots of people use the Provent brand I've had 2 on 2 different vehicles and have a small section of clear hose with a ball valve tap and drain it when changing the engine oil.

b1b
I would fit one to reduce the amount of oil mist which can coagulate with the EGR gasflow and cause build up in part of the intake. Usually most engines have the EGR flow nearer one end and that end suffers the most.
Having the EGR flow restricted by a plate still allows some EGR flow but lessens the volume of hot gas which can turn the mist into a semi solid GOOP which loves to deposit on intake internals and where it enters the INTAKE PORTS.
Many oils are crap and DO NOT SEAL rings very well and that allows for EXCESS oil vapour/mist to be exiting the engine and going to the intake via the turbo intake and through the intercooler. A dealer is UNLIKELY to use a good quality oil in your engine. If dealer serviced, check and ask what they use.
My engine has a catch can I made, and also has an EGR restrictor plate of 13mm dia instead of a 30mm dia port. It is positioned BEFORE the EGR valve so the VALVE runs cooler and less actual EGR flow gets to the engine intake in a given time. Too small a plate hole causes an ERROR fault.

I had the 3.2 for over 200k kms without a catch can. They are a pretty clean diesel. Mine got EGR system flushes twice with not much to report. Other brands are quite sooty. The clean involves running cleaner through the intercooler and whole closed loop while the engine runs for 1/2 hr. Was cool to see how dirty some brands are.
Not sure i'd bother with a catch can if I wasn't doing an EGR delete also? Most brands just do a EGR flush as part of a normal service these days. Costs me an extra $100 every few services with my current isuzu mazda. Makes the whole argument moot.

What I found.

I had a catch can fitted, was an upmarket one with membrain filter ahd pressure relief. Yes it collected a fair amount of oil but didn't stop all of it. The inlet manifold and EGR still got covered in carbon and becoming wet goo just took longer.

The oil vapour can act as a persudo upper cylinder lubricant and a mechanic I know who specialises in a particular model indicates he finds more valve seat errosion on vechiles fitted with catch after high milage. In the case with vehicles fitted with swirl control the oil vapour may also lubricate the bearings but not sure on that aspect?

I then tried the EGR plate and have found very little build up, I think the difference is if you reduce the carbon coming into the manifold it gets very diluted with the high air flow through the manifold so less to build up, whereas if you reduce the oil vapour the carbon coating is still due to the high carbon flow and eventually it gets wet even with a catch can fitted and more carbon builds up over time.

Which is actually the problem the oil or the carbon, the oil without the carbon does cause any issues. In my previous cars without EGR I never had an issue with with oil vapour from the breathers. It is the carbon in the EGR flow that causes the issue so it is the logicalto get rid of it.

I also tried and EGR defeat module. It worked ok around town totally inhibiting the EGR valve, I found though when towing it casued the engine to surge. Defeating EGR in my model vehicle also affects the Turbo dump as the dumped air path is back via the EGR valve. Before I puchased the module I questioned that aspect with the manufacturer and they said it didn't affect the turbo dump. They either didn't know the product did or they lied.

I have settled on an EGR reducing plate, has solved the carbon build up for me and does cause any other engine issues when towing.

An engine remap to inhibit EGR operation might be the go but make sure it doesn't affect the turbo dump.

The surging I mentioned above I believe is caused by inhibiting the EGR without taking other things into account. When the cars computer opens the EGR valve it lets bad air into the engine to reduce the flame burn temperature and this reduces power. If your sitting on a steady speed the the opening and closing of the EGR will cause surging and I suspect to overcome this the car manufacturers increase the fuel flow as the EGR valve opens to prevent the surging. The EGR defeat module only stops the EGR valve opening it does not contol fuel flow. Driving around town you don't notice anything but driving on a highway while towing a van van I found at certain speeds trailing the throttle or slowing accelerating the surging was evident. At least that's my theory.

I wonder how many boomers that swear blindly to the advantages of catch cans installed an upper cylinder lubricant kit in their Valliant when they bought the fluffy dice for the mirror?

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Are catch cans the new batteries?

Hi Bruce,

I've been a Diesel Mech for about 35yrs, mostly when they naturally vented to atmosphere, before the EGR and DPF systems came into play.

In the old days Catchcans weren't needed, oil vapour vented out to atmosphere so no oily build up in the intake manifold, these days oil vapour is recirculated back into the engine and can clog or build up in the intake manifold, all this to reduce emmissions.

Now before all of the backyard mechs and my mech collegues start stamping their feet here, remember this is my point of view and based on my experiences. There are varied opinions on catchcans, just watch you tube.

My story:
I do not and have never had catch cans in my cars.
My current 2020 Holden Trailblazer/Colorado has done 205k, all highway country kms so it runs at full engine temp all the time. It's rarely done stop start driving in the cities. It is serviced every 10k, and I change the engine oil every 5k. To date performance is almost as good as it was new. I have removed and checked the manifold and EGR and while there is some carbon build up it isn't worth cleaning out as it is so minor. I put this down to the type of driving I do and regular maintenance.

My view is it really really depends on how you drive your car, quality of maintenance and how long you plan on keeping it for. If it's new and you only want it for a few years I wouldn't bother with a catchcan. If you plan on keeping it for a while longer and working it then it can certainly help in the long run, but that also depends on how you drive it.

Honestly the 4wd Industry is an accessories sport, they all want you to buy the latest thing, but in most cases the latest thing is crap and isn't needed. It's up to you if you want to spend the cash.

Just my twobobs worth.