Volvo V40 1.8 HDI petrol (mitsubishi engine).71,000 miles.V plate
Failed MOT on emissions, co too high (0.38%).
Volvo tell me it needs a de-coke, plus hydraulic tappets, followers, & possibly injectors at a cost of £2,500 !!!
Is there any product I can put down the bores to shift the coke & get it through the MOT? Have already put injector cleaner in the fuel.
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Volvo V40 1.8 HDI petrol (mitsubishi engine).71,000 miles.V plate Failed MOT on emissions, co too high (0.38%). Volvo tell me it needs a de-coke, plus hydraulic tappets, followers, & possibly injectors at a cost of £2,500+!!! Is there any product I can put down the bores to shift the coke & get it through the MOT? Have already put injector cleaner in the fuel.
Hydraulic tappets is a known problem, although unlikely in itself to cause the emissions to be very high.
Coking up of GDi engines is also a known problem and expensive to fix. I don't think you have much of an option there - I can't see any of the Redex-type products helping.
I always steer clear of 'odd-ball' powertrain technologies until they are debugged and become mainstream. Direct injection of petrol has a chequered history - VAG FSI owners watch out!
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I bought my Volvo V40 GDi from my father at 43k and it already had noisy tappets. My father tended to drive in one gear too high and labour the engine (4th gear at 30mph etc), never booting it.
With 128bhp, the car pulls away without needing to put the foot down, but this means the engine never gets a good blast through with the throtle fully open.
My car is now at 78k and running better than ever.
I believe driving style has much to do with the coking problem.
1. I drive it very lean, never letting the rev drop below 2000.
2. If I need to accelerate, I always drop down a gear.
3. I am happy to put the foot the the floor, especially climing hills, keeping the car in a low gear and letting the engines top 5000rpm for as long is legal.
4. I also change the oil and filter every 5000 miles
5. and use Shell Optimax (Tesco petrol led to coking of the brake servo-unit).
Hope this helps
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I had problem with Mercedes Diesel emissions - Redex for 3/4 fills helped and using Shell Diesel rather than supermarket can help.
I now have S reg Mazda petrol, MOT'd yesterday - sailed though emissions - a great advert for Optimax.
£5.00 spent on Redex - if it works great - failing that you are no worse off than you are now (apart from the £5.00)
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Redex won't do anything for a GDi engine with bad coking. There is a technique using crushed walnut shells blasted into the bores - this is what the dealer do to clean them out.
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Exactly what we use to clean aero gas turbine compresors, throw the stuff down by the Lb fulls, pretty impressive at night as it comes out the hot end.
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The water injection method works well on traditional engines, but I am not sure how this would be with yours.
Find a small-bore air intake nipple on the inlet manifold (eg crankcase ventilation system) and connect up a long length of rubber pipe. Put your finger over the end, start the engine, and dip the end very briefly into a jar of water. Only let it suck in a tiny drop of water at a time. Rev the engine to keep it going. Only put in about a 1/8 " of water, a bit at a time. Give a final blast to clear, then turn off and leave.
Next start up will blast out all the steam-cleaned coke.
DO NOT LET IT SUCK IN MORE THAN A TINY DROP.
The idea is that it instantly vapourises the water, and the superheated steam cleans off the coke deposits. That bis why one symptom of a leaking head gasket is a suspiciously clean combustion chamber.
Better get an expert view first on the suitability for your engine, but I can vouch for this method on a variety of older engines, carb and injection. If I had known about it years ago it would have avoided all those old de-coke jobs we used to do.
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I believe this engine does not use a conventional EGO(lambda)sensor but a much more complicated and expensive device which does not check if the engine is running rich or weak but is supposed to tell the module how rich or weak it is-this may not be working properly.
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With reference to my earlier post, the proof that driving style affects coking is in the MOT Hydro-Carbon readings.
The first year after I bought the car from my father the HC reading almost failed (over 200ppm fails):
47,600 miles - HC 173ppm
56,500 miles - HC 63ppm
67,200 miles - HC 0ppm (obviously a reading failure)
77,400 miles - HC 13ppm (after 8 months exclusive Optimax use)
I believe that these readings show that the engine is cleaner now than it ever has been (sice the day it was bought). Driving style is the key to keeping it clean.
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