EGR Bypass - Any traps for new chums?

Submitted: Friday, May 08, 2009 at 14:51
ThreadID: 68639 Views:4357 Replies:6 FollowUps:4
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Doing a Exhuast Gas Recirculation bypass on the old 1992 1HD-T cruiser 80 series.

It seems to let a lot of oil that condenses in the recirculation hose, leak out past the joints all over the alternator etc and attracting dirt and causing various electrical problems.

It also makes everything immensely dirty under the bonnet any time you want to do even simple / regular maintenance like oil changes etc.

I decided to fix the root cause of the electrical alternator problems I was recently having thru oil and dirt in the alternator - by eliminating the oil leaking from the turbo hose from the air cleaner - where the recirc exhaust gasses condense in the pipe, bye installing a separate oil catch can - that can be emptied at oil change time.

Are there any traps for the unwary with such a modification?

I assume that because I've capped the oil vapour inlet fitting on the air cleaner, and run the oil vapour thru a new hose to the catch can - that the turbo boost etc should remain unchanged?

Anyone walked this ricepaper trail before me care to comment on any possible / hidden traps I've overlooked?

It turned out the "new alternator" I required according to the auto sparky - was not required at all, after I cleaned all the oily/ dirty connections on the back of it and flooded it with wd40 - now it's gone back to working like new again - saving some $660
thanks to the good advice I received from members here!

Thats why I figured to invest a few of those saved $ into the solution to the weeping oil leak problem from the tubo hoses, before it contributes to any more mysterious malfunctions.

I figure with the oil catch can, I can monitor how much liquid oil is comming out the Exhuast Gas Recirculation (Positive Crank Case Ventilation) outlet this way at each oil change as an indicator to state of engine wear.

When I run the engine with the egr hose off - vurtually no detectable oil vapour is present - obviously thats at idle and maybe it produces a bit more at highway revs...but I don't think blow bye is excessive yet with 325,000 km's on the engine from new based on what I'm seeing from the EGR line at idle.

Cheers and thanks in advance for any advice.
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Reply By: Member - Malcolm (Townsville) - Friday, May 08, 2009 at 15:36

Friday, May 08, 2009 at 15:36

I don't own an 80 series cruiser so cannot comment on that.

Just be aware that EGR and PCV are two different things. At least on the Patrol ZD30 of which I am very familiar with.

EGR allows the exhaust gases to be recirculated through the turbo thus cutting down on exhaust emissions.

PCV takes the fumes from the rocker cover and returns them to the crankcase. This is where the catch can is fitted and filters the oil out of the air before returning. I think you will find you will need to keep an eye on it at least every 1000 km. I have a ProVent200 fitted to mine.


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AnswerID: 363860

Reply By: Honky - Friday, May 08, 2009 at 16:07

Friday, May 08, 2009 at 16:07
To me an egr is used to add Burnt gasses to the intake to reduce certain pollutants.
Only started to be used in modern diesels or ealier in grey imports.
Couldn,t see them puting one in a 1992 if it wasn't legisalted at the time in Australia.
Plus the old oils in those day would have stuffed it up.

AnswerID: 363867

Reply By: Falco80 - Friday, May 08, 2009 at 16:25

Friday, May 08, 2009 at 16:25
I'm quite sure the 1HD-T does not have EGR. Are you talking about just adding an oil-catch-can perhaps?

AnswerID: 363872

Reply By: Member - Phil G (SA) - Friday, May 08, 2009 at 16:54

Friday, May 08, 2009 at 16:54
Yep, you don't have an EGR. They (unfortunately) appeared on Landcruiser diesels 10 years later.

But you do have a crankcase ventilation hose which is your problem!! If oil is leaking from the hose, then replace the hose and use decent worm clamps so it doesn't leak.

If you want to stop oil flowing down the hose (you'd be surprised at how little goes down the hose) then you can replace the hose with a longer hose, routing it upwards (so oil can't flow uphill).

Alternatively, you can install an oil catch can. Don't block the inlet on the air intake pipe. The catch can sits between the rocker and air intake so you are still applying a small vacuum to the crankcase. Main trap is not to constrict flow, which would pressurise the crankcase.
AnswerID: 363881

Follow Up By: Member - Nick (TAS) - Friday, May 08, 2009 at 19:56

Friday, May 08, 2009 at 19:56
Ive just fitted a catch can to our 1HZ with a turbo the turbo seemed to be sucking oil out via the PCV.I fitted the PCV hose into a can(to atmosphere) for a couple of thousand kms and no oil was presant in the can so believe it was the turbo sucking it out.I now have a catch can and PCV pipe hooked back to inlet piping and everything seems good.I have the catch can setup higher than PCV so any oil it catches drains back automatically.Just make sure that you dont restrict the PCV hoses anyway other wise you will start blowing crank seals.
FollowupID: 631578

Reply By: Horacehighroller - Friday, May 08, 2009 at 18:10

Friday, May 08, 2009 at 18:10
Re: the above poster suggesting a longer hose running uphill:

My old Mitsubishi 6 tonner used to have a hose (600mm long) from the rocker cover pointed straight down towards the ground (not recycled through the air cleaner.)

Every night it would dump about a teaspoon of oil on swmbo's driveway and required top-ups between services.

I removed the hose and repositioned it as close to vertical as I could and put an old plastic 2 litre milk bottle over the top to keep out any rain.
After that no more top-ups required (and obviously no oily driveway.

Oil definitely won't flow uphill.

In your case use the largest diameter hose that you can and run it uphill as far as possible before connecting back to the aircleaner housing.

AnswerID: 363900

Reply By: Flywest - Friday, May 08, 2009 at 20:37

Friday, May 08, 2009 at 20:37
Thanks guys..

I think you are correct about it being PCV (Positiver Crankcase Ventilation) now that I stop to think about it, after the comments above.

It is NOT exhaust gas being returned to the air stream to be reburnt at all it IS definitely indeed Crank Case ventillation via the top of the rocker cover being fed back to the air inlet via the air cleaner / turbo hose.

Now you have me worried tho.....

You see - I've run the outlet from the top of rocker cover to the oil catch can no worries!

However - i vented the catch can to atmosphere - RATHER than now returning it to the air cleaner (free of condensed oil - which theoretically should stay in the oil catch can) as has been suggested above!

You can actually hear the positive crank case pressure being vented to atmosphere as a low hiss if you drive with the window open.

It is no real problem (a bit more work) to plumb the outlet back to the air cleaner - but IF it is important to do so to maintain the correct cranck case pressure under turbo boost - then I can do so.

Have I understood this correctly please?

Many thanks again - I had a sneaky feeling there was more to this than I had remembered - which is why I posted this thread!

Cheers & thanks again
AnswerID: 363931

Follow Up By: Member - Nick (TAS) - Saturday, May 09, 2009 at 22:27

Saturday, May 09, 2009 at 22:27
I could never hear any hissing from my test catch can which was vented to atmosphere but got a oily smell at idle with window down.New catch can is vented back into intake.
It is illegal to vent them to atmosphere, if you get pulled over for vehicle check, its a big fine.
FollowupID: 631774

Follow Up By: Member - JohnR (Vic) - Sunday, May 10, 2009 at 07:34

Sunday, May 10, 2009 at 07:34
If you can hear it, it is the tell take to blow past of your piston rings. I have seen older engines like that, including a John Deere here after the guys had let it overheat. As they say, best it goes for burning into the air intake. I don't think you want to dirty the air cleaner though that much, with blow past oil. Nice and black!

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FollowupID: 631786

Follow Up By: Flywest - Sunday, May 10, 2009 at 22:48

Sunday, May 10, 2009 at 22:48
No worries - looks like I have a bit more work to do then - re routing the vent back to the aircleaner where I capped the inlet.

Ohh well - live & learn, another few hours of fun on the old 80 series!

I am guessing it will be OK after this - damn thing still drives like a limmo - I love it!

FollowupID: 631918

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