Oil catch cans?

Submitted: Saturday, Oct 14, 2017 at 21:41
ThreadID: 135747 Views:5042 Replies:10 FollowUps:20
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It seems to be a very important issue with all the modern small diesels especially when the kms start to get up, So why aren't the manufactures fitting them as a standard item?? They know the problems associated with this excess bypass sucked into the manifolds over time, And there all the same!!,

Cheers Axle
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Reply By: IvanTheTerrible - Saturday, Oct 14, 2017 at 22:07

Saturday, Oct 14, 2017 at 22:07
This question seems to be aimed at the manufacturers and I dont think many of them hang around forums.
Catch cans are a contentious issue. A lot of people think if you put the right oil in the motor you shouldn't need them. Vehicles have been running PCV's since the mid 70s with no problems and I've seen cars with a million ks on them. Like adding an extra fuel filter. Is it needed or is it just bullshit. All depends what armchair expert you ask.
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Follow Up By: Les - PK Ranger - Saturday, Oct 14, 2017 at 22:11

Saturday, Oct 14, 2017 at 22:11
If the vehicle has an EGR system, yes the catch can is virtually a god send in preventing the 'mix' or oil mist and EGR particulates, resulting in a tarred up manifold over time.

The other thing is, some of the oil mist MUST remain in the intercoolers of turbo diesels, as the mist would have a chance to cool and condense again as it passes through.
So over time this also has an effect on how efficient the intercooler performs.
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Follow Up By: RMD - Saturday, Oct 14, 2017 at 22:57

Saturday, Oct 14, 2017 at 22:57
It is the presence of an EGR system which is really the issue, IT turns the oil mist to goo in the intake manifold.
If there was no EGR system then the normal il flow through the intake system is not a problem. Even though turbos and intercoolers there is not problem. The speed of the air in there means the oil doesn't build up in an intercooler past a certain amount. Any excess gets blow through and burn in the intake charge.

Hundresds of Millions of engines have turbos and intercoolers with absolutely no problem, until EGR was incorporated in diesels.
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Follow Up By: Les - PK Ranger - Saturday, Oct 14, 2017 at 23:01

Saturday, Oct 14, 2017 at 23:01
Remove one or the other from the intake and the tar build up is negated.
The oil is the easiest (and legal) thing to address of the two.
It'll be interesting to get that intercooler out one day and check what's in there (if anything), but that'll only happen if I decide to upgrade to a PWR or similar.
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Follow Up By: RMD - Sunday, Oct 15, 2017 at 11:05

Sunday, Oct 15, 2017 at 11:05
Unless the oil becomes solid in the intercooler it will only deposit a certain "normal" amount and the rest gets blown through. The speed of the air ensures oil is always moved on. Some people seem to think they will get litres of engine oil out of their intercoolers.
Most intercoolers never get removed, with or without a catch can installed. There is nothing to block them.

A quick rinse with some petrol will flush any film away if you ever notice air cooling degradation. Dry it out of course before refitting.
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Reply By: Les - PK Ranger - Saturday, Oct 14, 2017 at 22:08

Saturday, Oct 14, 2017 at 22:08
They'll save 5c on a bolt if / when they can, a part like a decent quality oil catch can would give them total nervous breakdowns.
AnswerID: 614333

Reply By: Batt's - Saturday, Oct 14, 2017 at 22:30

Saturday, Oct 14, 2017 at 22:30
Yes definitely worth it, no their not all the same you need something that will actually do the job correctly, catch the oil mist and prevent it from continuing it's journey through the motor. Some vehicles will be chocked up earlier than others one of my neighbours 07 BT50 was ok when he fitted a catch can the other neighbours Navara had it's intake manifold about 30% chocked up with crap and he does more long distance driving.
AnswerID: 614334

Reply By: CSeaJay - Saturday, Oct 14, 2017 at 23:11

Saturday, Oct 14, 2017 at 23:11
I recon another reason it s not standard is that manufacturers do not want to introduce another servicable item. Imagine people who do not understanding the EGR (90% of people) and them faced with an item that needs to have dirty oil drained every 5,000km
AnswerID: 614335

Follow Up By: braggy - Sunday, Oct 15, 2017 at 07:04

Sunday, Oct 15, 2017 at 07:04
Surely,if they put a catch can in at manufacture, they would be able to design it so that it self drained back into the sump.
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Follow Up By: RMD - Sunday, Oct 15, 2017 at 08:43

Sunday, Oct 15, 2017 at 08:43
The so called 'Dirty oil" caught in a catch can can only be as dirty as the engine oil which it is where it comes from.

Some systems return the catch can oil to the sump, it is the same thing.
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Follow Up By: Batt's - Monday, Oct 16, 2017 at 11:39

Monday, Oct 16, 2017 at 11:39
Exactly that's a myth that has appeared a couple of times that the oil is dirtier when it comes from a catch can when it's the exact same oil running in the motor all it has done is travel through a rubber hose to the catch can.
Shouldn't need to drain it very often if it's a modern motor or an old one in good nick my neighbour checks his every few months doesn't get a lot.
I plumbed mine into the sump virtually maintenance free.
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Follow Up By: Member - Trouper (NSW) - Monday, Oct 16, 2017 at 19:30

Monday, Oct 16, 2017 at 19:30
The manufacturer wont do lots of things for 1 reason only the Cost. Better to let the punters do it. Imagine if there just one bolt that has a tendency to break somewhere and people say, "why didn't they fit a high tensile bolt? because that high tensile bolt cost an extra $1:50 multiply that by the 100s of thousands vehicles and you get the picture.
Cheers ..........Jeff
FollowupID: 884948

Reply By: Athol W1 - Sunday, Oct 15, 2017 at 08:04

Sunday, Oct 15, 2017 at 08:04
If the vehicle manufacturers fitted a decent baffle/filter system into the top engine cover then there would be no oil mist passing through the PCV system, and so there would be no need to be fitting any form of after market oil catch can system.

In days long gone before the introduction of the PCV systems the very same manufacturers used to fit suitable systems to prevent the oil mist from passing down the old Road Draft Tube (or walking stick), and subsequently leaking oil onto the road surface. With the introduction of the PCV that type of system was no longer seen as necessary, and as there is no perceived problem within the warranty period then the manufacturers will not spend the few cents that would be required to stop/reduce the issue of blocking manifolds that we are now seeing as vehicles age.

AnswerID: 614336

Reply By: HKB Electronics - Sunday, Oct 15, 2017 at 09:57

Sunday, Oct 15, 2017 at 09:57
A mechanic on another forum posted he has always found the engines fitted with catch cans to have lower compression ratios after many kms than engines not fitted with them.

It would seem though probably not intended that the oil ingested by the engine from the PVC acts as an upper cylinder lubricant reducing wear. Now some that fit catch cans also fit an oil injection system to overcome this issue.

Another issue is the residue still builds up though over a longer time but many have commented it is a lot harder to remove the residue from motors fitted with catch cans than those that don't have them as it is drier and sets harder.

To me seems like a lot of effort to get around the actual problem which is still there, that is soot from the EGR system being ingested by the engine. Some of the after market tuning mobs are now also de-activating the EGR system in the engine ECU's, there is also one company selling an add on unit for some models that is used in conjunction with an EGR blanking plate to completely block off the EGR flow without causing the engine computer to throw error codes, IMO one of these methods would be the way to go.

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AnswerID: 614338

Follow Up By: Member - Roachie - Sunday, Oct 15, 2017 at 10:53

Sunday, Oct 15, 2017 at 10:53
Provent 200 oil fume separator + both EGR's blocked off electronically (V8 Chevy has one on each bank of course) + fuel additive at every fill-up (Fuel Doctor) + FASS lift pump/water/air separation system ( https://www.youtube.com/watch?v=x4LCbGsujdU&t=182s )..... watch the video; you'll be ever-so-clever!!!

I think I have all the bases covered.
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Follow Up By: Batt's - Monday, Oct 16, 2017 at 12:09

Monday, Oct 16, 2017 at 12:09
I'm not a mechanic but I would find it hard to believe it would lower compression over time. Most of us that were fitting catch cans had older motors with high km so their compression would be down already and they had more blow by than usual. Have a look at older trucks their blow by was pumped out straight onto the road or ran down inside the chassis and look at how many km a truck engine would do before needing a recon millions. Older cars had it vented directly into the atmosphere via the rocker cover filter no pipe feeding it back into the engine.
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Reply By: pop2jocem - Sunday, Oct 15, 2017 at 11:36

Sunday, Oct 15, 2017 at 11:36
It seems to me that as previously stated, the oil mist from the crankcase, which has been getting fed back into the intake system of both petrol and diesel engines for many years has never caused problems. How much benefit, other than obvious environmental does that bring, is debatable. The "gunk" problem in intake systems that has become a real drama in many cases is being exacerbated by adding exhaust particles.
We now have diesel particulate filters (DPF) to reduce the release of these particles into the atmosphere. If the exhaust gasses that are being recirculated into the intake are taken after a DPF shouldn't that eliminate, or at very least minimise the effect of combining oil mist with exhaust gas?

Just a thought

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Follow Up By: Les - PK Ranger - Sunday, Oct 15, 2017 at 12:37

Sunday, Oct 15, 2017 at 12:37
Vehicles have an EGR system or DPF, one or the other.
Of course now there is Adblue into the picture to meet stricter standards.
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Follow Up By: Member - Roachie - Sunday, Oct 15, 2017 at 13:20

Sunday, Oct 15, 2017 at 13:20

My Chev Silverado had all three of those mentioned....EGR, DPF and Adblue. However, they seem to have disappeared and I know not where to.

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Follow Up By: Les - PK Ranger - Sunday, Oct 15, 2017 at 14:10

Sunday, Oct 15, 2017 at 14:10
Yeah ? Overkill much ??
Maybe the big dirty motors need all to meet emission targets.

Out of those the DPF may be the lesser of 3 evils, at least in some models.
From what I've seen on various forums, others like Pajeros seem to have real issues with DPF performance and limp mode.
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Follow Up By: pop2jocem - Sunday, Oct 15, 2017 at 14:50

Sunday, Oct 15, 2017 at 14:50
EGR and DPF have two different purposes. EGR to cool combustion temperatures by depriving the engine of oxygen during certain parts of the combustion cycle.
This reduces NOX emissions. Unfortunately reduced burn temps do not readily lend itself to complete combustion which contributes to an increase in unburnt particulate matter. Apparently up to 80% of these particles can be removed from the exhaust emissions by fitting a DPF. The downside is that like any filter these can clog up over time. This dependent on exhaust temps. Apparently temperatures in the order of 600 to 800 degrees C are required to perform a clean or regeneration as it is referred to. Long distance high speed runs or loaded should help. Pottering around town or short runs require a forced regeneration if the blocking is bad enough to throw up a warning light or the implementation of "limp" mode.

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Reply By: swampy - Sunday, Oct 15, 2017 at 14:07

Sunday, Oct 15, 2017 at 14:07

The problem is known about egr and pcv systems by the makers .
Most do work for a little while until there service is required to unblock and clean out .
Yes there was a service interval for EGR and PCV systems [not in all cars ] .
Apparently its cheaper to service the modern diesel PCV / EGR donot need cleaning
BULLSH*T to the manufactuers
Since they were released in Ozzy . although some models are/were effected worse than others .

Like most things deleted from the maintenance schedule .

To save 5cents per car is why nothing gets fitted to the PCV system

Actually the first Pcv recall to a turbo diesel I experienced was a tojam 1hz turbo
Some early `80 jap cars were very poor for burnt out EGR valves
AnswerID: 614343

Reply By: The Bantam - Sunday, Oct 15, 2017 at 15:16

Sunday, Oct 15, 2017 at 15:16
A few years ago there was a guy, posting on another forum.
He had just purchased a new common rail 4WD and a new excavator.
Upon close examination both had a pretty much identical engine from the same manufacturer.

What up set him was, that the 4WD had a very rudimentary fuel filtration system, typical of what would be found on similar vehicles.
The excavator on the other hand had a very comprehensive multistage fuel filtration system capable of handling large amounts of contaminant and delivering best possible performance.

Here lies the difference ..... Automotive manufacturers are absolutely focused on selling you for the highest possible price and delivering as little as they possibly can.
THEN making as much as they can after the sale.

Most Automotive buyers now very little at all about cars.

Go to earth moving and heavy transport it is a different world.
The owners and operators know a lot more about the vehicle and are a lot more involved in the maintanance ...... and the big players know every damn thing about every vehicle they run, in great detail and they know the costs involved.

This is why you will find things like very efficient oil, air and fuel filtration systems on earth moving and heavy transport and not on retail automotive.

But in those Industries, ya not going to get much choice of colour.

In retail Automotive, there are a whole range of things that are more important to buyers than how good the vehicle actually is.


OH .... if you want to see who is having a lend of who ..... see how much a lot of truck parts cost compared to passenger cars and how many models they fit.
AnswerID: 614344

Reply By: Gone Bush (WA) - Sunday, Oct 15, 2017 at 15:51

Sunday, Oct 15, 2017 at 15:51
I just emptied my HPD catch can. After about 5000kms there was about 200ml or so in it. I’m glad I fitted it.
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Follow Up By: Les - PK Ranger - Sunday, Oct 15, 2017 at 18:22

Sunday, Oct 15, 2017 at 18:22
That's a fair amount, and yes better than it going into the intake system.
The HPD use the steel wool type filter material in them ?

The Provent 200 type I have uses a paper filter, still fine after a good 100k . . .
On a 5k trip I estimate it takes out about 40ml to 50ml, in fact I don't bother saving it if draining at home, just put it into an old 1lt oil container marked 'used oil'.

Between services the amount used doesn't require topping off, otherwise I'd just put it back in the engine, which I do for simplicity when on road trips.

I've heard / read on forums of some vehicle makes using vast quantities of oil, like litres between services, and of course the manufacturers just say that's normal consumption . . . I wonder how much of that is 'blow by' which just goes back through into the turbo / intake, and is spat out with the emissions ?
Probably most of it.
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Follow Up By: Gone Bush (WA) - Sunday, Oct 15, 2017 at 18:30

Sunday, Oct 15, 2017 at 18:30

The HPD uses two stainless steel mesh filters that you can remove and clean.

No cost.

The others, I believe, have filters that are expensive when you need to replace them.
I wish I had kept note of the odometer reading when I installed it, and also I should have measured the amount taken out today, but it was quite a lot.

This, of course, is what you are trying to prevent by installing these devices.

I believe the engine in this picture had an EGR plate fitted. It had a 10mm hole to prevent fault codes popping up. Those plates with holes don't appear to achieve much.

There are quite a few businesses now offering an engine cleanup.

This is

This is

All photos in this post are from Landcruiser V8 diesels.
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Follow Up By: Jackolux - Sunday, Oct 15, 2017 at 19:13

Sunday, Oct 15, 2017 at 19:13
As said above HPD use a couple of Stainless Mesh Filters they don't use steel wool .
Last time I emptied my HPD it had 165mil of oil that was after just over 27k , I removed the outlet hose just to have a look , it was dry so I guess it's working as it should .
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Follow Up By: Les - PK Ranger - Sunday, Oct 15, 2017 at 20:02

Sunday, Oct 15, 2017 at 20:02
Wow, obviously a great addition for the Toyo V8s then.
First mod one should do I reckon.
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Follow Up By: Gone Bush (WA) - Sunday, Oct 15, 2017 at 20:21

Sunday, Oct 15, 2017 at 20:21
Most modern common rail diesels would probably benefit from these devices.
I'm glad I ain't too scared to be lazy
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Follow Up By: Member - Roachie - Monday, Oct 16, 2017 at 15:18

Monday, Oct 16, 2017 at 15:18
Now here's a funny thing.....

After I fitted the Provent 200, I drained about 200ml when I changed the oil after 10,000klm. No worries there.....I was using Caltex Delo 400LE at the time.

At that same oil change, I switched to Amsoil Premium 15w40 and installed a Amsoil dual bypass oil filtration system. This system enables MUCH MUCH longer intervals between oil changes.

After 10,000klm I checked the Provent 200 by opening the valve on the drain tube..... not ONE single drop came out.

After the oil had done 16,000klm I took a sample and sent it for analysis (still NO oil droplets in the catch can).....all the myriad of measurements they do were well-within spec. I changed the main filter, topped up the sump with another 200ml that I'd dropped to send off to the lab and now getting close to sending another sample off after the oil has done 30,000klm.

It's worth noting that I regularly check the dip stick and the oil is like honey and doesn't leave any staining on the fingers when I wipe the stick through them.

I have also recently checked the inlet and outlet pipes of the Provent and no sign of any oily residue there either.

It's almost a case of not needing a catch can if you have a good filtration system....there seems to be virtually no blow-by on this big Duramax engine now.

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