Why do turbos keep blowing!?

[duncanrp]

Alright.. So some of you may have seen my previous thread of me replacing my broken turbo on my 2003 Subaru legacy GT (Automatic). I ended up getting the car running again fine for another week and then low and behold it is now broken again.. Both times this has happened I have been driving at high speed in the country and with a bit of heavy acceleration.

The only thing I can think of causing this is lack of oil in the turbo, however when I replaced the last turbo I pulled the oil feed banjo bolt and cleaned the filter using brake cleaner.

Anyone else have any ideas of things to check when I next replace the turbo again?

Cheers.

[Kiwi_Fozze]

The vf38's are a terribly unreliable turbo. Best option is either replace with a td04 from the manual counterpart or the vf44 from the facelift legacy

[lachlan]

in what way are the turbos failing ? and what mods have you done to your car ?

[Marky]

Maybe get a post mortem done on one of them. Someone who knows what they're looking at will know if its been due to oil starvation or just seals going

Do they start to blow oil, sieze up, or just get a heinous amount of shaft play?

[duncanrp]

 kwi_fozze']The vf38's are a terribly unreliable turbo. Best option is either replace with a td04 from the manual counterpart or the vf44 from the facelift legacy

Yeah so I have heard, I wouldn't expect them to **** out this soon though

in what way are the turbos failing ? and what mods have you done to your car ?

The car has had no mods done to it. The first turbos shaft completely snapped in half in the center of the housings causing the compressor wheel to be rocking around on the compressor side.

[quote name='Marky said:

Maybe get a post mortem done on one of them. Someone who knows what they're looking at will know if its been due to oil starvation or just seals going

Do they start to blow oil, sieze up, or just get a heinous amount of shaft play?

Yeah I may do that.. I haven't noticed any oil being blown at all, or felt any seizing, it just sounds like there is a lot of play when accelerating (You can here it grinding on the housing). I will be pulling the turbo out at some point so I'll see if its the same result as the last turbo.

[boon]

Shaft breakage is usually FOD or complete lubrication failure - was the shaft discoloured at all? Discoloured = overspeed or no lubrication.

[SpeedySub]

I take it you have been replacing with second hand ones? If so have they been reconditioned, ie new seals etc? or are they straight from the original car. I'm thinking maybe they were on there last legs before they went into your car.

[lachlan]

Crank the car over without starting it with the oil feed undone /cracked loose and make sure oil actually comes out it when u replace a turb

[boon]

 SpeedySub said:

I take it you have been replacing with second hand ones? If so have they been reconditioned, ie new seals etc? or are they straight from the original car. I'm thinking maybe they were on there last legs before they went into your car.

Pointless fact of the day: turbo "seals" are actually just snap-rings that fit into grooves in the turbine shaft. They don't "blow" or anything like that, it's an incredibly common misconception. What happens is the bearings/shaft **** themselves, usually due to insufficient oiling, then the shaft develops radial play which lets oil past the seal.

Just for bonus points, the "seals" aren't really there to stop oil exiting the centre, they're actually there to discourage gasses (intake and exhaust) entering the centre section. The centre is under no pressure - in fact it should be under slight vacuum as it's functionally connected to the crank case via the oil drain. By the time a turbo is leaking oil it's probably completely koozed anyway - the exception being if it's mounted at a big angle, in which case it will weep oil past the seals but aside from some blue smoke and loss of oil there's actually nothing wrong with it doing that.

[duncanrp]

 boon']Shaft breakage is usually FOD or complete lubrication failure - was the shaft discoloured at all? Discoloured = overspeed or no lubrication.

I'll take a look when I take it out and let you know

I take it you have been replacing with second hand ones? If so have they been reconditioned, ie new seals etc? or are they straight from the original car. I'm thinking maybe they were on there last legs before they went into your car.

Yeah I have been. The replacement turbo I purchased did have some shaft play but I didn't think it was enough to be of concern.

[quote name='lachlan said:

Crank the car over without starting it with the oil feed undone /cracked loose and make sure oil actually comes out it when u replace a turb

I will do this when I get a chance.

[Marky]

Yeah, I've heard shaft damage due to overspeed or lack of lubrication is quite the issue

Discolouration is a whole new issue tho

Wait

[SpeedySub]

 boon said:

Pointless fact of the day:

Good to know, I am now better informed.

[duncanrp]

Does anyone have any idea exactly how much oil should be passing through the turbo oil feed line?

[duncanrp]

Alright so I disconnected oil feed to turbo and placed a container underneath to catch any oil, turned car to ignition to prime the pump. It sounds like the pump is trying to work but what do you know, no oil coming out AT ALL. Not even a little bit.

[Rosssub]

That's the fuel pump, not the oil pump. You'll need to disconnect the cam sensor or unplug the fuel pump relay. The turn the engine over (trying to start) to pump any oil.

[duncanrp]

 Rosssub said:

That's the fuel pump, not the oil pump. You'll need to disconnect the cam sensor or unplug the fuel pump relay. The turn the engine over (trying to start) to pump any oil.

Hey, I just disconnected the crankshaft sensor (below the altenator) and cranked the engine for about 10 seconds. Again, no oil was pumped.

[Marky]

That's not a superb sign

See if you can get the oil feed line off, it may (hopefully) be as simple as cooked oil blocking it up. I've seen it before a few times

Answers why they keep blowing tho

[Guest]

For some weird reason mine wouldnt pump oil thro line when it was disconnected but when hooked up worked fine. No clue why made no sense.

[lachlan]

Plain bearing turbos like about 3 l a minute . Bb turbos like about a litre a minute .

Have to be aware of where the restrictors are when swapping a turbo of different type . A bb will likely blow oil into the exhaust if fed 3 l a minute . In modern days the restrictor is built into the oil outlet .

Would ten seconds of cranking get the oil pressure light to go off ? Might not have pressure by then anyway if its jus been sitting . The turbo oil feed pretty much is the furtherest outlet from the oil pump

Maybe have the engine idling and crack the oil feed bolt loose and see if anything leaks out

[duncanrp]

 lachlan said:

Plain bearing turbos like about 3 l a minute . Bb turbos like about a litre a minute .

Have to be aware of where the restrictors are when swapping a turbo of different type . A bb will likely blow oil into the exhaust if fed 3 l a minute . In modern days the restrictor is built into the oil outlet .

Would ten seconds of cranking get the oil pressure light to go off ? Might not have pressure by then anyway if its jus been sitting . The turbo oil feed pretty much is the furtherest outlet from the oil pump

Maybe have the engine idling and crack the oil feed bolt loose and see if anything leaks out

Might be a bit hard to get at the oil feed bolt with the intercooler on as the intercooler and intercooler bracket are in the way when it is all hooked up and running.

[lachlan]

Lame

Join the afm straight to the throttle with what ever hose fits and start it up.

Is it possible to put the filter u cleaned in backwards and its blocked the flow ?

So how many km have u cooked 3? Turbos in ?

Do the numbers point towards something in thr car killing them or just unlucky and received pre worn out turbos

Edited October 13, 2015 by lachlan

[duncanrp]

 lachlan said:

Lame

Join the afm straight to the throttle with what ever hose fits and start it up.

Is it possible to put the filter u cleaned in backwards and its blocked the flow ?

So how many km have u cooked 3? Turbos in ?

Do the numbers point towards something in thr car killing them or just unlucky and received pre worn out turbos

Thus far Ive cooked 2 turbos. The one with the car when I bought it after 4 days, and the replacement 2nd hand turbo 3 days after replacing first broken turbo. I feel like something is causing it..

[Guest]

Clean the oil feed lines ?

[Kiwi_Fozze]

Yeah I'd be looking to remove oil feed lines and clean them out. Also remove the little filters....

[duncanrp]

Alright so I managed to run car while having oil feed disconnected. Oil actually came out this time! And there was a decent amount of it.

So.. could this really just be a case of ****ed turbos?