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How reliable are turbo-charged petrol engines. Also do you really, as rumour has it, have to let them cool down before switching them off?
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It's not cool down as much as spool down.
In other words don't be racing the thing come to a stop and switch off, you idle the car let the turbo spool down ie slow down so the oil runs through the bearings then switch off.
But as with most roads straight off motorway onto a A road at 40mph it will do it anyway.
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I'm on my third car with a turbo-charged petrol engine - 2 Audi 1.8Ts (both 150 PS versions) and the current 2.0T (200PS). Total mileage covered is approx 200k miles over a combined 10 years with no problems. The 1.8T VAG unit was widely used in the late '90s / early '00s, and I don't recall any widespread issues with it - in fact it's often 'tweaked' to much higher outputs without ill effect AFAIK.
I don't drive them any differently to other cars either; generally the last few miles of any journey are at lower speeds anyway so presumably the turbo cools down a bit then. Also I think modern turbo-charged engines are water cooled, and the fan will run-on to cool the car if needed
Peter
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Treat them the same as turbo diesels-most people wiil go thro' 30mph areas to get to work or home and that cools them sufficiently-just watch out for German motorway service areas where the pumps are the first thing you come to-most other EU service areas have sufficiently tortuous entrances.
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>> The 1.8T VAG unit was widely used
>> in the late '90s / early '00s, and I don't recall any widespread issues with
>> it - in fact it's often 'tweaked' to much higher outputs without ill effect AFAIK.
Apart from the widespread issue of faulty ignition coils, but it was sorted later on.
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>> Apart from the widespread issue of faulty ignition coils, but it was sorted later on.
Aye but that wasn't the turbo, that affected all their petrol engines, all sizes (even the v8's etc) and turbo or NA. There's still a recall ongoing.
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Reliability has to be worse than an NA engine i'd have thought - an extra component = multiple extra potential failure scenarios.
Anecdotal but on Briskoda petrol turbo failures dont really come up, I can't remember any and there are plenty of mega miles engines on that forum. In contrast, with the more complex turbo's fitted to diesels, failures are not unknown. Might just be diesel's a far more popular option for owners though?
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I think its because there is much more soot dispersed in diesel oil, that it makes it easier to block, clag up, or carbonise in the turbo bearings. Plus there is soot (the turbo driven vanes are upstream of the DPF remember) to deposit in the turbo.
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Another problem is this new-fangled stop start technology - won't allow you to cool your turbo effectively unless you actively disengage it on every start up (well BMW anyway)
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I think the issue is much overdone. At M-way speeds (in the UK anyway) the typical turbo engine is using a small proportion of its rated output. And trundling along in traffic might overheat the driver, but not the engine. I dare say there are exceptions: like the Cromwell road (London) traffic light races to the next red light, the parts of the Autobahn that aren't clogged, and Alpine passes.
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>> Might just be diesel's a far more popular option for owners though?
Samples like those are inevitably biased - those interested in non-mainstream car choices are more likely to join specialist forums and thus to write about every aspect of ownership, good or bad. I would bet that Briskoda's turbo diesel drivers generally work their cars harder, for longer, than that forum's turbo petrol drivers, therefore more turbo diesel failures are to be expected from the sample.
These days a turbo petrol engine should be no less reliable than any other kind. If a few operating hints can be garnered from the internet (cf. DMFs, DPFs et al) then so much the better for the user.
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>> I would bet that Briskoda's turbo diesel drivers generally work their cars harder, for longer
Sounds about right -- mega miles on the motorway, you'd buy a diesel.
The one thing the petrol guys do that's not so common with the diesel guys is take them on track, that could inflict a few thousand miles wear in short order. Another thing is tweaking them for higher outputs and still using them as daily drivers. Stage 1 / 2 / 3 performance mods must be pretty stressful on the turbo, but they still don't go bang.
Not enough of a sample though. They have to fail at some point. Not too hard to replace either, i could do that on my driveway without much sweat, access is pretty alright considering. Common enough part to be cheap but when mine gives up the ghost i'll buy a hybrid to fit i think.
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As mentioned in another thread my current, and previous petrol engined cars are / were both turbocharged, and high mileage. Neither had any noticeable loss of performance, and neither were anything less than clockwork reliable. 141k on a Golf GTI 1.8T, and 153k on a Volvo S60 2.0T.
Many turbo failures in the old days were down to the inadequacies of mineral based, or even early synthetic oils in coping with the turbo's operating temperature of 800-900°C. Not only would the oil break down very quickly, with the resulting loss of protective capability, but it could "cook" inside the turbo bearings and eventually starve them of oil.
Modern turbochargers have better cooling, and good quality modern synthetics are much more resistant to high temperatures. Assuming the recommended service intervals are strictly followed, and of course the engine not abused, I would expect 150+k from any modern turbo engine without undue problems.
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Well I hope that the turbos on petrol engines are better than the one on my diesel engine that has just given up the ghost.
There are other issues and damage as well - I have already chopped it for a new car.
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>> Well I hope that the turbos on petrol engines are better than the one on
>> my diesel engine that has just given up the ghost.
>> There are other issues and damage as well - I have already chopped it for
>> a new car.
You never liked the beemer anyway. What will be the replacement steed?
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>> You never liked the beemer anyway. What will be the replacement steed?
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An Audi A5 Sportback. Not one of the fast ones - just a two litre diesel with an automatic gearbox - but plenty quick enough for me.
BTW, the BMW was an "economic write off" (to quote the dealer) at only 77k miles. I was a bit shocked, I can tell you.
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Reliability of turbo-charged petrol engines - Bigtee
