Tell me about...turbochargers.

[Uncle Jimmy]

Specifically those in petrol cars. I have a basic understanding of what they do and how they work.

But do they often wear out? Do they go bang and chuck their contents into the cylinders or do you get a slow deterioration?

What warning signs of a knackered turbo can you see/hear/feel?

[DSdriver]

I don't know about how they fail but a friend found that it is much cheaper to buy a replacement from Garret than Saab.

[Station]

The bearing in the turbo has a constant 'feed' of oil, so it is no actually touching any surfaces or getting friction (like an engine cylinder piston).

They go bang when the bearing wears out, the quality of oil deteriorates or stops completely, then the turbine disintegrates and goes through the inlet into the valves/pistons. The seal can also go, which leads to black smoke from the exhaust on boost.

[sierraman]

Depends, a lot now are used in a low pressure application which inevitably means a longer life. Its people's treatment that kills them, turning engine straight off after a run, running old thick oil. Signs would be lack of power, whistling or similar, smoke through worn bearings/seals. Oil all over the shop in the induction isn't a good sign.

[Junkman]

Turbochargers are made by the Devil and must be avoided at all cost.

[Luckythirteen]

Part of Pa's service routine for the Legacy and the Focus: pop the boost pipe off and run a finger round the inside of it.

When the Legacy's turbo went, it caught him by surprise though. No boost, nasty squealing noise: diagnosis crapped up oilways leading to partially seized turbo.

Surprisingly delicate little things are turbos. Happy to spin away when all is well, but upset them st your peril.

[Bobthebeard]

Turbochargers can rotate at a frightening speed. Something like 150,000 rpm I recall. Any problem with the lubrication at those speeds will cause terminal borkage. As others have said, look after the turbo, keep up to oil and filter changes and it should* last for a long time. Petrol engines less likely to grenade than diesels in the event of failure.

[Coprolalia]

Get a supercharger instead.

Preferably an obscure one like the G-lader.

It'll never grenade*.

[jonny69]

You can re-spell it 'turbot' as a hilarious alternative way of describing it on the internet.

[Mr_Bo11ox]

Turbos are flippin marvellous, I love them. Hope this helps

[alf892]

Turbot is nice too. Won't knacker you engine even if the fins come off

[dollywobbler]

Turbos are flippin marvellous, I love them. Hope this helps

 

I see our viewpoint is very similar but in a rare event, I shall reply to your praise rather than start a separate post that says exactly the same thing.

[gordonbennet]

Never had a pertol turbo, but have covered probably 3 million miles in turbocharged Diesels and can't recall a single failure.

 

As above re servicing, regularly with a reasonable quality oil and good filter.

 

Drive it with sympathy, let it warm up before asking it to work hard and let it cool down gently on tickover after it's been working hard, given care they should last the life of the vehicle.

 

By the way, modern lorry training tells us not to let it tick over any more now the Gucci oils are so wonderful, bollocks, my way (Frank) has seen me so far, buggered if i'm changing now to suit the fashionistas...a cupful of fuel versus twin turbochargers 40 ton wrecker and downtime, i'll take the cup of fuel every time..

[rainagain]

Never had a pertol turbo, but have covered probably 3 million miles in turbocharged Diesels and can't recall a single failure.

 

As above re servicing, regularly with a reasonable quality oil and good filter.

 

Drive it with sympathy, let it warm up before asking it to work hard and let it cool down gently on tickover after it's been working hard, given care they should last the life of the vehicle.

 

By the way, modern lorry training tells us not to let it tick over any more now the Gucci oils are so wonderful, bollocks, my way (Frank) has seen me so far, buggered if i'm changing now to suit the fashionistas...a cupful of fuel versus twin turbochargers 40 ton wrecker and downtime, i'll take the cup of fuel every time..

This don't allow to warm up anymore is an EU ruling I believe. I remember having a laugh reading the hand book for my mums old Yaris. Under winter driving it said if the temp was below zero you should allow the engine to run for five minutes before driving off unless you lived in Germany in which case you were good to go at the turn of the key. So either they had amazing magic oil in Germany or it was environmental bollocks

[Pillock]

Get a supercharger instead.

Preferably an obscure one like the G-lader.

It'll never grenade*.

Absolutely! And they definitely don't* put a mesh over the inlet on the high pressure side to catch the bits when it doesn't* grenade.

 

(At least it saved me a new engine. Still got the bits of scroll somewhere)

[willswitchengage]

Like an turbine engine, a non-variable geometry turbo has one moving part, and its functionality is dependent on its bearing components moving as intended.

 

The bearings will failure through either:

 

1. Manufacturing defect - unlikely these days with improving quality control processes

2. Fatigue - statistically controlled by bearing manufactures and exacerbated by poor maintenance, i.e. poor lubrication

 

Obviously turbos can also fail from insults to the turbine components, but this would require a failure of another engine/air intake system component.

 

Variable Geometry Turbos (VGTs), whilst still surprisingly simple, are active components and come in various designs with varying degrees of maturity. Obviously they are more complex and therefore have more failure points that are less controlled.

 

A turbo failure will not 'grenade' an engine unless it rejects debris into the intake by receiving an insult that damages the compressor. A bearing failure will just cause the shaft to seize, it will not cause direct damage to the engine.

[skattrd]

Another fan of turbos here.

They make noises that make me smile as well as as making cars go fast. Mine go "whoosh" or "flutter flutter" depending on whether or not a dump valve is fitted.

 

I've not had one go completely on me yet, but when the one on my Mira was on the way out it wouldn't keep constant boost pressure at full throttle, it fluctuated a bit. On dismantling it there was quite a bit of play in the shaft (ooo-er).

[Dead_E23]

I am currently not such a fan.    The one in my V70 appears to have knackered oil seals at 150k and as there doesn't appear to be a rebuild kit available I'm looking at parting with a lamentable amount of money for a recon (or preferably a rebuild if I can find somewhere decent to do it)

 

It is also so tucked away down the back of the engine that I can barely see the damn thing, so extracting it promises to be a chore.  

 

Fiddlesticks!

[skattrd]

The usual places normally rebuild turbos for around £200.

I'm sure if you remove the turbo, get the codes of it you should be able to find a rebuild kit for it somewhere.

 

Oh, and removing the turbo is often the hardest part opf any work on it. The heat they generate often leads to bolts/nuts shearing and rounding.

[Volksy]

I am currently not such a fan.    The one in my V70 appears to have knackered oil seals at 150k and as there doesn't appear to be a rebuild kit available I'm looking at parting with a lamentable amount of money for a recon (or preferably a rebuild if I can find somewhere decent to do it)

 

It is also so tucked away down the back of the engine that I can barely see the damn thing, so extracting it promises to be a chore.  

 

Fiddlesticks!

 

I changed the one on my old S70, pointlessly it appeared, as it was a partially blocked PCV system causing the smoke. It was indeed a twat of a job. It was made a little easier by having use of a mates two poster ramp, as access from underneath is better, not something I'd like to do on my back though. 

 

I got a second hand one from Salvo, which was about £70 delivered. 

 

[Dave_Q]

I am currently not such a fan.    The one in my V70 appears to have knackered oil seals at 150k and as there doesn't appear to be a rebuild kit available I'm looking at parting with a lamentable amount of money for a recon (or preferably a rebuild if I can find somewhere decent to do it)

 

It is also so tucked away down the back of the engine that I can barely see the damn thing, so extracting it promises to be a chore.  

 

Fiddlesticks!

 

I would exhaust all other avenues before assuming it's the turbo.

 

On most turbos there isn't really a seal as such between the oil and air parts, the oil is kept in by pressure difference.

Both the comp and turbine sides are under greater pressure than the bearing housing and this keeps the oil in.

 

Generally the bearings have to be seriously worn to create enough play in the rotor system to allow oil out, at which point you'd have other symptoms like no power, bad noises etc.

 

Check for PCV issues as suggested by Volksy, and any other sort of inlet or exhaust restriction such as blocked filters/cat, also check for a kinked or collapsed oil drain tube from the turbo before writing it off.

[twosmoke300]

Isn't it in and out play (axial) rather than side to side play( radial) that means a goosed turbo?

[Dave_Q]

Isn't it in and out play (axial) rather than side to side play( radial) that means a goosed turbo?

 

Well, either really, depending on what is worn...

 

I'm only familiar with 1 particular brand but as well as journal bearings (radial control of shaft motion) there is also a thrust bearing for axial control.

 

Specs should be available as to what this play should be so if you have a DTI you can check yourself.

 

From my experience of a short work placement in the service department of a turbo OEM, journal bearing issues are far more prevalent and mainly caused by oil issues - contamination, starvation, hot shutdowns. 

 

Foreign object damage is also quite common but the most common "failure" is misdiagnosis.

A vehicle goes to a dealer with smoke, low power etc, dealer replaces turbo, nothing wrong with turbo when inspected.

 

All this is based on heavy duty diesel stuff but passenger car petrol turbos are basically the same but smaller.

[Dead_E23]

Thanks all - some useful comments there, so I shall investigate further.  

 

The engine has a voracious appetite for oil at the moment (~ 200 miles per pint of 0w30), so it needs investigating sooner rather than later.  

 

Some interesting symptoms that require further investigation:  i) sharp right hand turns occasionally generate a huge puff of oil smoke as if the oil is pooling somewhere ii) accelerating after being on a trailing throttle sometimes makes a bit of smoke, but nothing like as much as i).  

 

I shall have to see where the pipes go and get my thinking cap on.

[Mr_Bo11ox]

I used to work for Garrett turbos. Considering how finely machined the shafts and bearings are in these things, they are incredilbly tough I think and a bit of a marvel of technology. The only advice i can really give is dont skimp on oil & oil changes, and the turbo should pretty much last forever (Renault DCi excluded obv). What Dink says about the seals is right, theres not really a seal as such just a metal piston ring which is designed to bed itself in early on in the life of the turbo. If your turbo engine is smoking a lot or breathing heavily its rarely the turbo thats actually to blame. More likely something up with the breather system whcih causes oil to blow past the turbo's piston rings.

[forddeliveryboy]

It seems the more awkward to get at, the more likely to fail. For the first time ever I had a turbo-related failure when the oil supply pipe rotted, which being a crosswise engine in a newish car (post 90s) was a pita to replace. It was made of monkey metal, as you'd expect on a modern.

[Dead_E23]

I will report back once I've investigated a bit.    Must say, part of me quite likes leaving clouds of blue smoke - feels quite nostalgic.  

 

The rest of me grinds its teeth at having to make increasingly frequent purchases of hatefully expensive newfangled oil.

[New POD]

IF and it's a big IF, you service a turbo'd car with decent oil, more frequently than the manufacturers spec, always drive in gently until the oil is fully warm, always allow the turbo to cool at idle after a long run, (you get heat transfer that cooks the now stationary oil in the centre housings, THEN a turbo will be reliable.

 

Things start to go wrong if the waste gate actuator fails, (but should fail to a safe open position) (Or if hoses split) or if you chip the car for more power, or start to look at hybrid turbos or big boost.

 

Obvious wear out on the seals, will result in oil being sucked into engine, through the compressor end, or into exhaust through the turbine end.

 

 

When I worked at Garrett making turbos in the late 90's, Ford would pay about £80 for a simple waste gated turbo, and a Ford Dealer would sell it for £800.*  They had a rebuild plant Near Stockport employing about 150 people, where they had 1000's of old turbo's taken in exchange and they would strip, clean, remachine and reassemble, balance and test to an equivalent spec.  They sold them to so called specialists, who could also buy parts and do it themselves. All seals and bearing used to be available for a home rebuild, but you do get into balancing issues. (It's very sophisticated kit to balance a centre housing assembly)

 

What always amused me was the price of aftermarket actuators.  We used to pay less than £3 for an actuator, and I've seen them out there for £150 with the "right" spring. 

 

* I have found that generally the mark up from OE supplier to Dealer price is a factor of about 10.

[skattrd]

 All seals and bearing used to be available for a home rebuild, but you do get into balancing issues.

 

I read on www.homemadeturbo.com that balancing is not necessary if you are not modifying the wheels or vanes. The spindle and wheels will have been balanced when it was new and if you are not changing anything it should still be in balance.

If you are concerned about balancing then most places that offer a rebuild service will balance for you.

 

The turbo I rebuilt a few years ago has done 20k miles since rebuild without being balanced.

[Richard]

Oh, and removing the turbo is often the hardest part of any work on it. The heat they generate often leads to bolts/nuts shearing and rounding.

 

Sheared bolts needn't be a problem.