I have a ford focus mk2 1.6tdci, it's failed it's mot on emissions, it's usually .50 on the test but this year it's jumped to around 2.50 which is too high for a car of its age, a euro 5 which had a top limit of 1.50 emissions, there's no lights on dash saying anything is wrong and the car seems to be running sweet, I've cleaned the egr which seemed which wasn't very dirty anyway, I've also taken off the dpf and cleaned that out which didn't seem very dirty, pcv seems intact after I inspected it, the only thing I can find is quite a bit of oil on the intake side of the turbo, it's trickled down into the airbox at some point, the intake turbo fins are covered in oil also, I took the turbo off to inspect and had to pour oil out of it as in attached pictures, I wonder could this be the culprit that's sent the emissions up??? Any advice greatly appreciated.
Leaking turbo seals, can they cause high emissions???
- Thread starter sonofrob
- Start date
I'm a big fan of the "Italian tune-up". With turbo diesels, I have a theory...
Oil gets into the inlet tract, mainly because, (as you've seen) it gets past the turbo seals, and via the crankcase breather. It enters as a hot mist and, (in theory) goes back into the engine and gets burned. However, I think that when the car is relatively gently-driven, a lot of it condenses on the walls of the inlet tract, the inside of all the intercooler fins, and the inlet manifold. This, eventually forms a sticky mess in there - possibly made worse by the entry of hot gas from the EGR valve.
(Me scraping gunge out of my sister's elderly Freelander 1 inlet manifold, with a lollipop stick).
My theory is that at maximum power, (where the air demand into the engine is greatest, the rush of incoming air will "scour" a lot of this gunge away from the walls of the inlet tract and intercooler and burn it in the engine. My evidence, is that engines run consistently hard, tend not to do it as badly as ones that are gently driven. Further evidence was that then I used to borrow Mrs. Avocet's car and booted it, I'd see a lot of smoke in my mirror, but the second time I booted it, I'd see less, and the third time, hardly any.
In order to create big airflow, you need to be close to maximum RPM and have the throttle wide open. It's no good just revving it in neutral. You need the turbo generating maximum boost. This is best done whilst towing a heavy trailer up a long hill, because you really need to give it a bit of time to do the "scouring" and if you do it in a low gear, you're likely to hit the rev limiter after a few seconds. If you do it in a high gear, you're likely to lose your licence...
So if it was my car, that's the first thing I'd try. Take it for a decent run and work it really hard. Absolutely foot-to-the-floor (without over-revving) for as long as you dare. I like to give it (say) at least three 10 second blasts at max power each month. Mrs. Avocet's car (and my dad's old Freelander) used to emit much less smoke at high revs after that.
Just one thing though... Euro 5 introduced particulate filters. You shouldn't get this on a car with a DPF, because the DPF should filter the smoke out?
Oil gets into the inlet tract, mainly because, (as you've seen) it gets past the turbo seals, and via the crankcase breather. It enters as a hot mist and, (in theory) goes back into the engine and gets burned. However, I think that when the car is relatively gently-driven, a lot of it condenses on the walls of the inlet tract, the inside of all the intercooler fins, and the inlet manifold. This, eventually forms a sticky mess in there - possibly made worse by the entry of hot gas from the EGR valve.
(Me scraping gunge out of my sister's elderly Freelander 1 inlet manifold, with a lollipop stick).
My theory is that at maximum power, (where the air demand into the engine is greatest, the rush of incoming air will "scour" a lot of this gunge away from the walls of the inlet tract and intercooler and burn it in the engine. My evidence, is that engines run consistently hard, tend not to do it as badly as ones that are gently driven. Further evidence was that then I used to borrow Mrs. Avocet's car and booted it, I'd see a lot of smoke in my mirror, but the second time I booted it, I'd see less, and the third time, hardly any.
In order to create big airflow, you need to be close to maximum RPM and have the throttle wide open. It's no good just revving it in neutral. You need the turbo generating maximum boost. This is best done whilst towing a heavy trailer up a long hill, because you really need to give it a bit of time to do the "scouring" and if you do it in a low gear, you're likely to hit the rev limiter after a few seconds. If you do it in a high gear, you're likely to lose your licence...
So if it was my car, that's the first thing I'd try. Take it for a decent run and work it really hard. Absolutely foot-to-the-floor (without over-revving) for as long as you dare. I like to give it (say) at least three 10 second blasts at max power each month. Mrs. Avocet's car (and my dad's old Freelander) used to emit much less smoke at high revs after that.
Just one thing though... Euro 5 introduced particulate filters. You shouldn't get this on a car with a DPF, because the DPF should filter the smoke out?
