Techie question regards Honda Civic turbo

[Loneranger]

Hi Folks,

Hoping some of you techie folk may be able to help me out.

Appreciate its not a fronty but thought I would ask here first, hope that's ok.

I recently fitted a reconditioned turbo to our Honda Civic 1.7 cdti, what a task that was. Anyway all has been good until about 2 weeks ago when I developed an oil leak. At first it seemed to be coming from the return oil feed pipe and connection, so new pipe and clip sourced and off when went again, Seemed fine again for a day or two and then a very small drip of oil was apparent under the car.

After scratching my head I asked Stuart (Fatbaz) and another mate Colin if they could have a butchers at it for me. Had the opportunity to use a ramp which made things a lot easier. On first inspection again Stuart and Colin also thought it was leaking from oil return feed, it only happens when the car is running.....

Stuart then noticed where it was coming from.....





Contacted the turbo supplier and they have suggested that the turbo isn't at fault ( no surprise there) and that the issue is probably being caused by vacuum or pressure issues to the turbo. Apparently lack of vacuum can cause to much oil being pressed against the seals and when you rev the car the seal seems to swell and allow oil to pass it.

I believe if there wasn't enough pressure the turbo would run roughly, the car actually runs fine and is lacking no power. My thought is that there must be a problem on the vacuum system.

Thought I would ask here as we seem to have a vast amount of knowledgeable folk, is anyone able to tell me how I test the vacuum system.

Its a Honda Civic 1.7 cdti 54 plate.

Cheers Pete

Hope its ok here admin wasn't sure where to put it as it isn't fronty related.

[RatCav]

Lack of vacuum?? Surely then your brake pedal would be rock hard as well.

Have you joined the Honda Civic club. There must be one out there. Or even phoned a Honda specialist in the area.

[RatCav]

Looking at the picture am I right in saying that it is leaking from the housing join. That would mean its busting past the main shaft seals. I think its a dodgy turbo to be honest.

[DarrenH_2.2]

the oil seals stop oil getting from the lubricated bearing surface, to the non lubricated surface the cross shaft and compressor/exhaust turbine

so this gentleman is correct, a lack of boost or vacuum could make it leak, but it would leak into the compressor or exhaust turbine, not externally all over the casing.

to me its clear cut manufacturing/assembly fault

[RatCav]

Ok I am old school. Why would a turbo need a vacuum?

[Loneranger]

Sorry Neil I don't really know the answer, I believe the pressure pushes the oil into turbo and the vacuum help it through and back to engine but I may be talking utter tosh.

I have also posted on Honda forum but theres no community like the FOG community.

Pete

[RatCav]

I can understand oil being pushed into the turbo from where ever the oil pump is pushing it from. Then it has a party lubricating the bearings etc, then has to leave. I fail to see why a vacuum would be necessary as it would leave via the path of least resistance (the oil drain) back to the sump and not through the casing joins. Unless of course the return is blocked.

[snapper]

As neil suggested, the oil return to the engine is going to be a mix of gravity with a bit of a push from the oil going through the bearings. The only time I can imagine there being a vac on the turbo (with a petrol) is the Manifold Vac that's generated before the turbo kicks in.

Out of interest, why was the original turbo removed? Did it have a spectacular break up? If it did then I suppose it's possible that there's bits in the oil return pipe causing a blockage, unlikely yes, but possible.

My gut feeling, considering it's a re-furbished turbo and would have 'died' at some time in it's life and then been bench striped for repair is that you have a duff turbo there.

[Loneranger]

Ok guys thanks for all feedback.

The Honda kept going into limp mode and the fault was down to the turbo itself, didn't actually break up. It was something to do with variable vanes. (again I am probably wrong)

As the turbo refurbisher has suggested its vacuum or pressure I guess I need to check before I go down the route of taking the car off the road again and throwing the turbo back at them.

I did do some more searching with may or may not be a bad thing. EGR's kept getting mentioned and also EVRV - electronic Vacuum Regulating Valve so I guess to things for me to check over.

The car is a diesel by the way.

All thought are still welcome.
Pete

[DarrenH_2.2]

pressure drop across air filter and housing causes vacuum at inlet of compressor (at idle)

lack of vacuum in crank case (i,e it pressurising due to engine wear and windage) could hinder the drain

as per my previous reply i dont believe either of these would present as external leak.

of course, we are not diagnosing the actual problem with these guesses, just trying to work out wtf the guy on the phone was on about.

[Loneranger]

Thanks Darren....

[RatCav]

Cheers

[Loneranger]

Sorry, Thanks everyone Neil, Frank and Darren.

[Fatbaz]

You could get a vacuum before the turbo if the air filter was heavily soiled.

lack of boost pressure and exhaust gas pressure in the respective areas will allow oil to seep into the respective "snails".

But here you can see that the oil is leaking out of the joint between the main bearing/shaft housing and the snail. When Pete blipped the throttle you could see snail pushing away from the main body, this seemed to "pump the oil out of the joint.

So if the turbo was OK oil seeping from the seals would remain inside the turbo, ether passing through the engine from the inlet snail or directly into the exhaust from the exhaust snail. The oil should not be coming out from the joint of the 2 casings.

Presented with the above I'd say the turbo is naff (being polite here)

Incidently the oil return from turbo to sump is clean and clear. the return pipe has a bigger bore into the sump from the turbo than the oil outlet port on the turbo so I guess it's not restricted in anyway.

I'm a heavy diesel specialist and don't know too much about small common rail diesels with variable vane geometry turbos so am a bit stuck when it comes to knowing what the turbo supplier is refering too when they advise Pete to check the vacuum and pressures, can any of you guys that work on passenger cars for a living shed any light on what is being referred too by the turbo supplier.

Regards
Stuart

[DarrenH_2.2]

[Fatbaz]

As I though Darren though I'd of use the term "bollo- no can't writer that here as it's a family site!

Regards

Stuart

[DarrenH_2.2]

first rule of turbo remanufacturers/vendors

1) blame it on the recipient engine
2) blame it on who fitted it to the recipient engine
3) blame it on the boogie