Turbo killing

[cwspellowe]

Right before I strap my knee up and get under the car, I want to pose a few questions about what could have popped this time with the motor.

What basically happened was I was pulling onto the motorway in 3rd from 2krpm up to about 4.5-5krpm, as if I was doing a 30-70 run. As it hit the higher end of the rev range I heard a bang/pop noise, like a blown boost hose, and black smoke billowed out everywhere to the point I couldn't see outside the car.

Pulled over, engine was still idling, so I knew it wasn't a rod being spat or a lack of compression. There was reek up the rear bumper and oil in the exhaust, and a puddle of oil forming below the back of the block. The oil feed looked ok, was dry, and the top half of the turbo looks clean.

The underside, it's hard to tell, but the back of the block and the underside of the turbo are oily. The engine lost enough oil to go from the max line to under the min line but there's still just enough in the sump to register on the dip stick.

When the engine idles, you can see oil dripping from somewhere at the back of the block but iirc no real amount of smoke, no more than cold veg startup anyway, the occasional white puff.

My thoughts are either oil seals on the hotside of the blower or oil return line blowing off/splitting.

Reasoning?

Inlet pipes are clean so the coldside is fine, from my experience if one seal goes that badly, the impeller shaft is knackered and takes the other side out too. No oil in cold side.

If hotside seals go, oil comes pouring out the exhaust. The exhaust IS oily, but I wouldn't say drenched. If turbo oil pressure was that high it destroyed the seals, the whole thing would have been flooded as an engine can be emptied of several litres in seconds with the oil pressure.

Oil is down the back of the block and the underside of the turbo. In my head, if i'd got the oil return wrong, pressure could have built up and blown the oil return pipe. I didn't measure the pipe diameter scientifically but it was definitely a bigger bore than the T2 line. The layout seems to be unrestrictive too and i'd have expected smoke before a blowout of all the oil if it was restrictive and caused a buildup of oil.

I'm just wondering if excessive boost has blown the turbo, but I can't explain why oil is both on the outside of the turbo/engine, and down the exhaust and under the rear bumper. Unless travelling at 70mph*ish has caused oil to be dragged along under the car with the airflow.

Suggestions?

I'm hoping it's not another turbo as from my setup, the only thing I could think would be excessive pressure but it peaked at just over 30psi and the turbo was in good nick before fitting, i'd hope it would last longer than 10 seconds at high psi, even at that pressure.

FYI, it was being run de-wg with no actuator while I was waiting on a billet actuator being fitted. This was the first run I had it over 20psi as i'd been cautious on its few outings with it being wet and SO MUCH TORKZ. y0.

Sorry, /essay. Need to figure out what went wrong and why though.

[Piggy]

sounds like oil return to me

[cwspellowe]

Even though it's in the exhaust?

The fact I heard something pop under pressure points me to a split pipe too, i'd have thought a seal failing wouldn't have made that noise. At first I thought it was a boost hose until the smoke billowed out from the engine bay.

Forgot to say.. was the first ever high boost run, it had driven normally up to that point. So something's happened with high RPM/high oil pressure

[Toms306]

Only going on my experience with blowing the golf exhaust oil seal - the oil came out everywhere, the cat was loose so came.out there but also out the tail pipe and up the bumper a bit.

However there was no odd noise, just a tonne of smoke everywhere while driving. Cold starts with it blown weren't actually that smokey, I guess idling from cold there isn't enough heat in the turbo/exhast to burn the oil.

And it doesn't necessarily empty oil quickly, I did a good 15 miles with smoke billowing out and didn't actually lose much oil, considering how bad it looked anyway. It was only about half a litre, max to min on the dipstick.

So I reckon you're right with that tbh, doesn't take long to whip off the exhaust nuts and check anyway.

[cwspellowe]

You'd be surprised Tom, when the coldside popped it emptied a measured 1.2L of oil into the intercooler in not a long time at all!

It definitely went "wheeeeEEEEEE-POPFFTTT" though.

It COULD have been the return line being shite, bigger turbo, lower return line adapter, slight S-shaped return as the turbo side of the return line sat lower geographically than it would on the T2.

Trying to think, i'm sure it was still able to make boost after the pop, which is what set alarm bells ringing before the smoke as a burst boost hose means no boost at all. Can't remember though.

[Ruan]

Does it make a horrible racket?

I can't believe it's another turbo, when a turbo goes you usally hear the PFOOOPT *clink clink* and then *SCREEEEEEEEEEEEEEEEEEEEEECH* of the poor turbo...

Pull off the IC pipe, see if there's metal bits in there...

[cwspellowe]

No Ruan, sounds normal, i've started it a couple of times to move it about the drive and it idles and takes low RPM's fine, just drips oil somewhere down the back.

I'm just trying to convince myself that's not another £150 down the pan, but if it is it must be user error, trying to figure out WHY it would pop.

[Ricky]

How was your oil return routed? Does it go down to the sump or does it go down then back up the down again to the sump like an S shape? Thinking oil could have collected in the bend?

[cwspellowe]

Nah it's a very shallow "S", very similar to the standard metal return line on the T2 but the barbed return flange on the turbo is about 40mm long, so the first bend in the "S" sits a bit lower than standard. Obviously the blower's a big bigger than a T2. On level ground though it doesn't look like it bends upwards, not even horizontal.

[Ricky]

Ah ok, its one thing that's worrying me about mine, oil collecting and filling the compressor with oil, if that's even possible.

[Piggy]

the thing confusing me is its running oil out of the exhaust...

is it still doing that or was it just oil blow back under the car due to speed??

hope it aint pricey dood

[Jonny81191]

I know it'd be a massive coincidence, but what if it's both? Maybe your return line was already leaking a bit, (not uncommon, let's be honest) and it was your hotside seal that went, causing the big loss of oil?

But you say the exhaust wasn't drenched, indicating the leak was from the return line...

I dunno, just thinking "out loud" really

[Piggy]

not headgasket...oil only side at the back...?

[Toms306]

You'd be surprised Tom, when the coldside popped it emptied a measured 1.2L of oil into the intercooler in not a long time at all!

It definitely went "wheeeeEEEEEE-POPFFTTT" though.

It COULD have been the return line being shite, bigger turbo, lower return line adapter, slight S-shaped return as the turbo side of the return line sat lower geographically than it would on the T2.

Trying to think, i'm sure it was still able to make boost after the pop, which is what set alarm bells ringing before the smoke as a burst boost hose means no boost at all. Can't remember though.

I'd guess it depends how badly the seal failed as to how much comes out then.

This might be completely irrelevant but is your supply line bigger ID than the return line? As (in my head!) that'd cause a pressure build up between the two, and when the pressure has no-where else to go it'd have to burst out through the weakest oil seal, hotside in this case.

Just for reference, mine still boosted perfectly and even managed a couple of overtakes on the way haha. Tbh I didn't even think about the oil loss, I was worried about the oil in the cold side so checked that was clear, then just headed home asap. It also sounded and drove fine slow speed after the event.

[Dum-Dum]

Valve stem oil seal on the exhaust side of the engine maybe?

[cwspellowe]

Could be Chris. Decided im going to remove the blower tomorrow and assess the damage. Not in a position to get it back on the road yet but may as well investigate!

[Eeyore]

good luck mate. Will be good to see this on the road again! Hopefully Ill actually get to see it this year!

[Tom]

You must be getting quick at these turbo changes now!

[Ruan]

Valve stem seal would cause CHRONIC blue smoke... It weeps into the cylinder when off and the tell tale is the MASSIVE cloud of blue a few seconds after starting...

I'm going to put money on oil feed/return issue...

[Jonny81191]

^ Agreed mate, if it's dripping down the back of the block at idle, the return/feed must be leaking..

TBH I'd still want to take it to bits and look at the seals though. How else would oil get actually IN the exhaust?

[Ruan]

Yeah, this... Does sound like it's possibly popped a seal...

Other than oil from before... I'd be taking it to bits to inspect, it's not worth leaving it...

[cwspellowe]

Oil from The previous failure is a possibility. I didn't clean the exhaust up and only did about 15 miles on the new turbo so could have been that, there's hardly any oil on the bumper where it exits. Chronic turbo failure would have blackened the bumper and the majority of smoke was from the engine bay.

[Dum-Dum]

I really do think you have 2 issues here. one causing oil in exhaust and one causing the drip.

[Piggy]

or oil in exhuast from previous fail???

[cwspellowe]

Oh dear. It died, now it dead.

Really need to find out what killed le turbo

[Piggy]

really?! turbo dead....weird...and sorry for you pal

[cwspellowe]

Meh, I've started budgeting each month for a new turbo

Will post pics when I'm home but can't see an obvious reason for failure...

[Harky]

I'm sure you've checked or got rid of it already, but what about the filter gauze on the return line, its not blocked or anything.

Whatever it is I hope you get it sorted

[Niall]

I doubt its oil stem seals. After i did my first rebuild with the wrong seals, that leaked over 1l of oil into the exhaust in less than 50 miles and the smoked chronically and also left the exhaust damp with oil. Even if you shat a seal completely, i cant see it blowing all that oil that quickly!

oh and have you checked you havent suffered racoon filter failure?

[cwspellowe]

Definitely not raccoon filter it was the first thing I checked.

Just typing up a new thread with LOTS of pictures. Let's get our thinking caps on..