Oil Breathing/Rocker Gauze

[pablito81]

Hello,

Happy new year to you all, I've just got back from a quick visit to Montreal- I had forgotten how nice it is in Canada and how friendly everyone is!

I've had my van (2.8D) back from the mechanic after a main oil seal failure on engine. Previously, the crankcase breather had been blowing oil into my turbo and so I had disconnected it, with a light mist coming out on idle when warm, but no major loss of oil.

My mechanic said the most likely cause for the seal to fail was excess crankcase pressure, due to a blocked gauze filter in the rocker cover (apparently a known problem on the 4m40 engine??) which blowing oil from the breather was a likely symptom of. He said that I should replace the rocker cover/clean out the gauze to solve.

I've cleaned out the gauzes- there's two and they're pretty fine, so not surprised they block! Job is slightly complicated as you need to take off some rivet heads in the rocker cover to remove gauze assembly and then reassemble. Having done this however, my engine is still blowing oil mist from the detached breather hose, which I had expected the job would have fixed.

My first question is- can anyone confirm what is 'normal' in terms of this breather hose? Should it blow, or suck? And presumably with no oil mist?

My second that is my mechanic suggested that leaving the dipstick slightly out should vent any crankcase pressure if it does occur....can anyone confirm if this is going to work?

From research it seems many people leave the breather unattached and have a oil catch can, but having paid a few hundred bucks to fix the oil seal, I don't want to leave it if blowing oil is a symptom of something else the matter in the engine that's going to lead to another repair bill.

Many thanks in advance,

Pablo

[Artacoma]

Some thoughts on oily air.
I had a pinched breather hose that blew my cover gasket , also made the van push a lot of blue smoke.
But once I straightened the hose and replaced the gasket all was fine.
That said I think the breather hose always pushes a bit of oil through to the turbo.
I know guys have installed filter cans to catch this oil but I think that adds an unnecessary maintenance step and the oil that does go through probably helps lube the turbo. Although this oily air does go thru the intercooler as well. My intercooler has a film of oil on the inside and i wonder if it would be more efficient if it had only dry air.
Hmmmmmm....

[mararmeisto]

The oil breather is connected to the air loop AFTER the turbo, so all the suspended oil in the air is doing is lubricating the inside of the no-moving-parts intercooler.

[Artacoma]

The oil breather is connected to the air loop AFTER the turbo,

I don't think it is on my van , If it was I think it would pressurize the valve cover .
I'll take a look under my hood once this frosting of snow melts

[pablito81]

Breather on mine is ducted to before the turbo- hence when it's connected turbo spits oil everywhere!

Not sure if having the oil in there is a good or a bad thing- probably good if the oil were mint-clean, not so good if the oil is in normal condition.

[psilosin]

On the L400 the return is located pre-turbo just after the air filter. Nothing good about that oil vapour, not needed to lube the turbo. It's a symptom of blow-by, lots of it is a bad sign.

[mararmeisto]

Right, sorry, I meant after the air filter, so I guess it is going through the turbo first and then the intercooler.

[MardyDelica]

what oil ur using.
it should be 15/40 truck diesel oil
whats the mileage u for now on your L400
if higher maybe sign of blow by
hope this help
cheers;
Mardy

[pablito81]

Using 15/40 semi-synth catrol magnatec (don't know if you get that in Canada, but seems to be the favoured oil of UK deli owners), mileage is about 90k.

Truck is otherwise running fine- no smoke in exhaust and doesn't seem short on power. I'm guessing if it were blow-by there would be a lot of oil coming out? It's always only a fine mist- I've left the hose open for a couple of thousand miles and all I have is a thin film of oil near where it is venting.

[MardyDelica]

hi, i see the problem now. we also have soem in here.
first what year is your L400, if less than 2002 model L400,
you can used synthetic only when its winter not summer.
but in the summer or less than 0 degree you can used regular 15/40 diesel oil use by heavy truck.
15/40 synthetic has afine layer of oil, that oil by pass your ring and other exhaust valve then go to turbo and oil breather hose.
synthetic is good but not alwasy good when the car and metal parts was made before they invented the synthetic oil,
which is year i guess 2000 or 2001 when it start.
try to used regular 15/40 diesel oil maybe this help and then go further.
it works for me to all my L400 that i sell.
let me know if it works.
thank you
Mardy

[nxski]

Mardy, there are many Delica owners around here that use semi or full synthetic. Are you saying that this is not good? (since there were all made before 2000)

[psilosin]

I get less vented oil when using synthetic oil than conventional in both my Surf and L400 so I would disagree with that blanket statement. Try different oils and see how they work for you, some your engine seems to like better than others.

I haven't been able to test too many different oils in teh L400 yet since it is always broken down and parked , but in my Hilux Surfs unless it was hot hot they were not that happy with conventional dino 15w40...oil catchcan was always filling up. Hardly any oil vapour accumulated in teh catchcan when using Synth 5w50 or synth 15w40.

And do not think that just becasue your engine is diesel that HEAVY DUTY DIESEL oil is the ONLY oil available for your vehicle. In fact none of the available diesel oils in canada are perfect for the small japanese motors, most of the diesel oils here are meant for big work truck engines pulling bigger loads (Severe duty). Diesel oils built to a higher specification than CF-4 (ie: CH-4, CG-4 and CI-4) may have too strong an additive package them with and using with our little engines under normal duty mild loads (ie day to day driving) can theoretically can glaze the bores pretty quickly...but what you gonna do...import a japanese diesel specific high ash oil like Castrol J-MAX?? Probably not so just hope for the best. An alternative to Heavy Duty diesel oil that my Surf loves in the winter is Castrol Synth 5w50 and it always seems to be on sale at Costco or CdnTire (not just for gasoline engines, rated for turbo diesel and TDi engines on the bottle in case you don't think I have a trusting face...).

[MardyDelica]

well,
i study this before to some of my client and talk to some of my friend who is a heavy duty mechanic.
there answer is that those year they never made the right metal yet to support the synthetic oil which has a thin oil layer on it.
you can used synthetic when its really cold does not affect much as the metal expand when its cold. but when the weather is hot and u used synthetic you see the diff. you might loose oil cause of the thin layer.
i agree with you psilosin, that vw tdi uses some synthetic or all of them but those year 1996 they dont have the tdi new generation to support this. it will turn out it might blow by or run out of oil if keep using in summer hot weather.
synthetic for me is good in the winter no problem. but summer i dont think so.
think about big truck even newer engine some of them dont used synthetic in the summer.
were talking of synthetic using in the summer in this case ok. not winter.
now when you used 5/50 in the winter depends how cold its good and bad. too thin when the engine warm up.
again its up to the people which one to used everybody has there own opinion.
thru my test for most of this L400 the best synthetic u can use up to -30 i guess is 5w/40, not 5w/50 as it too thin.
might loose some oil and result no oil from the bearing.
thats all what i mean. anybody can used what they want. just be careful to check the oil all the time ok.
cheers;
mardy

[psilosin]

you can used synthetic when its really cold does not affect much as the metal expand when its cold

Not in this universe...

I think you just relaying old fashioned misinformation about synthetic oils and not looking at the actual chemistry of todays synth oils. Synth oil does not just exist as some thin layer like you are saying. It exists at the stated viscosity and does so under more extreme conditions than conv oils can. It does tend to have the property to adhere well and leave a nice protective thin layer on metals which is why it is so much better for preventing damage at startup...less metal on metal waiting for oil pressure to build. You should not see increased blow by from using synth oil.

[MardyDelica]

well , i dont think its an old fashion way this day,
its just thru my experience on some of the car i put synthetic as you saying.
it wont hold the oil level.while if i put regular 15/40 diesel oil in the summer or warm weather the level of the oil
is still good.
even some of my client do used the synthetic in warm weather.temp of engine goes up and lack of oil when run it for a while
may cause engine failure later. again its up to the person if what they like.
as far as i know diesel highway truck usually dont used synthetic in the warm weather.as it wears down the bearing and engine component as its very thin layer of oil for synthetic.
talk to one of my friend who is a professor , mechanic & license inspector in bcit teaching the newer mechanic.
about synthetic oil when using it or not in a older engine.
his answer is its up to the person if wish synthetic or regular oil for diesel.
but recommend to me just to used regular oil 15/40. and when i do this no problem at all for me.
you just have to try, some time it work sometime it does not.
everybody has there own opinion.
cheers: